[Title will be auto-generated] by Helen Critchell

PHYSIOLOGICAL PROFILE OF ELITE JUNIOR BADMINTON PLAYERS IN SOUTH AFRICA

Kerry Ann van Lieshout

A Dissertation Submitted to the Department of Sport and Movement Studies, Rand Afrikaans University, Johannesburg for the Degree of MPhil (Sport Science)

October 2002

ABSTRACT

There is a lack of descriptive data on the physiological and physical profiles of elite junior badminton players in South Africa. The purpose of this study was to measure and describe the body composition, aerobic power, muscular characteristics, speed, flexibility and agility of the elite junior badminton players in South Africa. Eight male and seven female badminton players between the ages of 14 and 18 years who were selected for the junior national badminton squad of South Africa participated in this study. The players participated in the following field tests: multistage-shuttle run; vertical jump; lunge jump; sit-ups; push-ups; forwards and backwards speed at 2,4, and 6m and the SEMO agility test. Each subject was tested on the Cybex II Isokinetic Dynamometer to determine absolute and relative peak torque of the hamstring and quadriceps muscle groups, the functional and conventional hamstring:quadriceps ratios, as well as the arm power-endurance ratios.

Flexibility was measured using the Leighton

Flexometer. The following means (+ SD) were observed for the male players: height 180.4 (8.1)cm; mass 73.4 (9.7)kg; body fat 9.6 (1.6)%; somatotype 3.0:4.1:3.1 (1.0:1.1:1.0) and VO2max 50.7 (3.0) mlO2.kg-1.min-1.

The female

players had the following means (+ SD): height 161.2 (4.3)cm; mass 58.1 (7.9)kg; body fat 19.2 (4.5)%; somatotype 4.0:4.3:2.0 (1.0:1.1:0.7) and VO2max 42.0 (2.8) mlO2.kg-1.min-1. The physical fitness components of the players in this study that were found to be weaker than the norm, and would need to be improved greatly included their aerobic power, leg power and flexibility.

Other fitness areas that were not

necessarily found to be a weakness, but could be improved further to enhance their game, is their hamstring strength, eccentric leg strength, upper body and abdominal endurance, backward speed and agility.

DECLARATION

I declare that this dissertation is my own, unaided work except to the extent indicated in the acknowledgements and by the reference citations. It is being submitted for the Degree of Master of Sport Science at the Rand Afrikaans University, Johannesburg. It has not been submitted before for any degree or examination at this or any other university.

_______________________ day of __________________ 2002 ____________________________________ (KERRY ANN VAN LIESHOUT)

__________________________________

Date: _________________

(signature of student)

____________________________

Date: _________________

(signature of supervisor)

iii

TABLE OF CONTENTS

Chapter

Page

INTRODUCTION

1.1

Background to the problem

1.2

Statement of the problem

1.3

Delimitations

1.4

Limitations

1.5

Concepts

1.5.1

Physiological profile

1.5.2

Elite

1.5.3

Junior

1.6

Assumptions

1.6.1

Assumption one

1.6.2

Assumption two

1.7

Scope of research

LITERATURE REVIEW

2.1

Introduction

2.2

Physical characteristics

2.2.1

Introduction

2.2.2

Body composition

2.3

Metabolism

2.3.1

Introduction

2.3.2

Aerobic metabolism

2.3.3

Anaerobic metabolism

2.4

Muscular characteristics

TABLE OF CONTENTS

Chapter

Page

2.4.1

Introduction

2.4.2

Strength

2.4.2.1

Leg strength

2.4.2.2

Arm strength

2.4.2.3

Abdominal and back strength

2.4.3

Power

2.4.4

Muscular endurance

2.5

Speed

2.6

Flexibility

2.7

Agility

METHODOLOGY

3.1

Subjects

3.2

Training

3.3

Testing procedure

3.3.1

Introduction

3.3.2

Anthropometry

3.3.3

Flexibility tests

3.3.3.1

Test protocol

3.3.3.2

Shoulder flexion and extension

3.3.3.3

Shoulder internal and external rotation

3.3.3.4

Trunk lateral flexion

3.3.3.5

Trunk flexion and extension

3.3.3.6

Hip flexion

TABLE OF CONTENTS

Chapter

Page

3.3.3.7

Hip extension

3.3.3.8

Hip external rotation

3.3.4

Field tests

3.3.4.1

Multistage shuttle run

3.3.4.2

SEMO agility

3.3.4.3

Muscular endurance tests

3.3.4.3.1

Sit-ups

3.3.4.3.2

Push-ups

3.3.4.4

Speed

3.3.4.5

Explosive power

3.3.4.5.1

Sargent vertical jump

3.3.4.5.2

Lunge jump

3.3.5

Isokinetic dynamometry

3.3.5.1

Introduction

3.3.5.2

Isokinetic test protocol

3.4

Statistical analysis

RESULTS AND DISCUSSION

4.1

Introduction

4.2

Body composition

4.2.1

Height

4.2.2

Mass

4.2.3

Percentage body fat

4.2.4

Somatotype

TABLE OF CONTENTS

Chapter

Page

4.3

Aerobic power

4.3.1

Maximal oxygen consumption

4.4

Muscular characteristics

4.4.1

Concentric strength

4.4.1.1

Absolute peak torque

(i)

Hamstrings

(ii)

Quadriceps

Relative peak torque

(i)

Hamstrings

(ii)

Quadriceps

(iii)

Hamstring:quadricep ratio

4.4.1.2

4.4.1.3

Discussion

4.4.2

Eccentric strength

4.4.2.1

Absolute peak torque

(i) 4.4.2.2 (i)

Quadriceps

Relative peak torque

Quadriceps

4.4.2.3

Discussion

4.4.3

Power

4.4.3.1

Leg power

4.4.3.2

Arm power-endurance

4.4.3.2.1

Absolute arm power

(i)

External rotators

(ii)

Internal rotators

Relative arm power

100

4.4.3.2.2

vii

TABLE OF CONTENTS

Chapter

Page (i)

External rotators

100

(ii)

Internal rotators

100

(iii)

External:internal ratio

100

4.4.3.2.3

Discussion

101

4.4.3.2.4

Endurance ratio

102

4.4.4

Muscular endurance

105

4.5

Speed

109

4.6

Flexibility

115

4.6.1

Shoulder flexion and extension

118

4.6.2

Shoulder internal and external rotation

118

4.6.3

Trunk lateral flexion

119

4.6.4

Trunk flexion and extension

120

4.6.5

Hip flexion and extension

120

4.6.6

Hip external rotation

121

4.6.7

Discussion

122

4.7

Agility

124

CONCLUSION AND RECOMMENDATIONS

127

5.1

Introduction

127

5.2

Body composition

128

5.3

Aerobic power

130

5.4

Muscular characteristics

131

5.4.1

Strength

132

5.4.2

Power

133

viii

TABLE OF CONTENTS

Chapter

Page

5.4.2.1

Leg power

133

5.4.2.2

Arm power

135

5.4.3

Muscular endurance

136

5.5

Speed

137

5.6

Flexibility

138

5.7

Agility

138

5.8

Summary

139

REFERENCES

141

APPENDICES

151

Informed consent form

152

Timetable and instructions for testing

155

Data collection sheet

157

SEMO agility test

159

Sample of physical fitness evaluation report submitted to

161

Badminton South Africa F

Sample of physical fitness evaluation report submitted

170

individual subjects

ACKNOWLEDGEMENTS

My sincere gratitude and appreciation is extended to the following people who contributed to my research project: My parents, for their continual support, help, patience and guidance, and Hylton for his encouragement, patience and understanding. Mr A.J.J Lombard (my supervisor), for his help, guidance and faith in my research project. Mrs M. Robinson for proof reading my dissertation. Mrs L. Du Plessis and Mrs D. Allen (BSA national coaches) for all their help with the organising and testing of the junior badminton players. Badminton South Africa for funding the transport and meals of the subjects. Philip, for his help and guidance at the laboratory, and Janes for helping out with the statistics. The families who kindly hosted the subjects from provinces outside of Gauteng: the Kerr family, the Beaurain family, the Allen family and the van Lieshout family. All the badminton players who willingly and enthusiastically took part in the research, and their parents who allowed them to be tested.

Without their

cooperation the study would not have been possible.

LIST OF ABBREVIATIONS

ATP

adenosine triphosphate

body weight

centimetre

con

concentric

dominant

D CE

dominant leg concentric extension

D CF

dominant leg concentric flexion -1

deg.sec

degrees per second

et al.

et ali.i (and others)

ext

extension

ext.

external

flex

flexion

FTa

fast twitch fibre Type A

FTb

fast twitch fibre Type B

gram

i.e.

id est (it is)

int.

internal

kilogram

km/hr

kilometres per hour

LIST OF ABBREVIATIONS (continued)

left

metre

millilitre -1

mlO2.kg .min

-1

millilitres oxygen per kilogram per minute

mmol/lt

millimols per litre

sample number

non-dominant

ND CE

non-dominant leg concentric extension

ND CF

non-dominant leg concentric flexion

Newton metre

OG92

Olympic Games 1992

percentage

phospho creatine

+/-

plus minus (approximately)

right

RAU

Rand Afrikaans University

ROM

range of motion

rot.

rotation

rpm

revolution per minute

xii

LIST OF ABBREVIATIONS (continued)

standard deviation

sec

second

slow twitch fibre

VO2max

maximal total body oxygen consumption

yrs

years

xiii

LIST OF FIGURES

Figure

Page

Somatotype (mean + SD) of males and females.

Maximal oxygen consumption (mean + SD) of males and

females. 3

The muscular characteristics (mean + SD) of males (n=8).

The muscular characteristics (mean + SD) of females (n=7).

The leg power (mean + SD) of males and females.

The

absolute

and

relative

arm

power

characteristics

arm

power

characteristics

(mean + SD) of males (n=8). 7

The

absolute

and

relative

(mean + SD) of females (n=7). 8

Arm endurance ratios (mean + SD) of males and females.

104

The muscular endurance (mean + SD) of males and females.

107

Forward speed (mean + SD) at 2,4, and 6m of males (n=8)

111

and females (n=7). 11

113

Backward speed (mean + SD) at 2,4, and 6 m of males (n=8) and females (n=7).

Agility (mean + SD) of males and females.

125

xiv

LIST OF TABLES

Table 1

Page 60

Physical characteristics of the elite junior male badminton players.

Physical characteristics of the elite junior female badminton players.

The hamstring:quadricep ratio of elite junior badminton players.

Eccentric quadricep strength of elite junior badminton players.

Flexibility of the elite junior male (n=8) badminton players.

116

Flexibility of the elite junior female (n=7) badminton players.

117

CHAPTER ONE:

1.1

INTRODUCTION

BACKGROUND TO THE PROBLEM

There is a lack of descriptive data on the physiological and physical profiles of elite junior badminton players in South Africa. Junior players are required to have a good stroke production and physical fitness, as well as psychological characteristics that will enable successful performance at the competitive level. The sport-specific technical skills in racket sports are predominant factors. The physical fitness of a player however, can be a decisive determinant of success during a tournament (Smekal et al., 2001). This coincides with Groppel and Roetert (1992) who reported that the physical requirements of raquet sports demanded efficiency in a number of fitness components.

A racquet sport player

would need to develop higher levels of the basic physical qualities to be able to compete effectively against stronger opponents (Groppel and Roetert, 1992). Chin et al. (1995), recommend that if a player wants to achieve reasonable success in international badminton competition, improvements in physical fitness needs to be emphasised in addition to skill training. It is useful to build up a normative database of physical fitness components thought to be important in a particular sport in order to compare young athletes’ performances at various levels (Elliot et al., 1989).

Physiological profiling has been recommended in the popular literature by Groppel and Roetert (1992) for purposes of fitness assessment and developing norms, as well as for establishing a basis for longitudinal tracking. The test data obtained from physical fitness testing provides a good

baseline

and

reference

for

coaches,

sports

scientists,

physiotherapists as well as future researchers. The comparison of test scores of any one player with data from a normative base of many players enables strengths and weaknesses to be identified.

This plays an

important role in designing individual physical conditioning programmes according to sport specific demands, motivating players to train, and leads to the development of the players as well as the sport as a whole (Mahoney and Sharp, 1995). The purpose of this study was to measure and describe the body composition, aerobic power, muscular characteristics, speed, flexibility and agility of the elite junior badminton players in South Africa.

1.2

STATEMENT OF THE PROBLEM

This research proposes to determine the physiological profile of the elite junior badminton players in South Africa.

1.3

DELIMITATIONS

The study will be limited to male and female badminton players in the under nineteen junior national squad and will not take into consideration any alternative sports the players may participate in during the research period.

1.4

LIMITATIONS

There are only eight male and eight female elite junior badminton players in the South African junior badminton squad, and only seven of the females were able to participate in the research. Unfotunately, due to injury during the testing, two of the female subjects were unable to participate in some of the tests. Another major limitation to the study is the fact that badminton is a relatively small sport and as a result, not much research has been completed on the physiological aspects of badminton. This resulted in a lack of literature on some of the aspects of the physiology of badminton players, especially that of junior players. No normative data could be found on physiological profiles of elite junior badminton players in South Africa, and the lack of comparative data in badminton made comparisons of data difficult.

1.5

CONCEPTS

1.5.1 Physiological profile

The physiological profile refers to the physical characteristics that distinguish badminton players. This includes body composition, aerobic power, muscular strength, muscular endurance, speed, flexibility and agility (Omosegaard, 1996 and Chin et al., 1995).

1.5.2 Elite

Elite refers to the top male and female junior badminton players selected for the junior national squad.

1.5.3 Junior

Junior refers to male and female badminton players who are 18 years old or younger.

1.6

ASSUMPTIONS

1.6.1 Assumption one

The players are at their highest physical fitness condition at the peak of the badminton season when the assessments will be performed.

1.6.2 Assumption two

The players will perform the fitness tests to the best of their ability.

1.7

SCOPE OF RESEARCH

Each junior age group category (under 15, under 17 and under 19) has one main major tournament for the year - the South African Badminton Championships. It is normally the last tournament of the season and this is the tournament that all the players train for and strive to win. Prior to this championship tournament, four other tournaments are held in different provinces of South Africa which lead up to the South African Championships.

The first of these tournaments normally starts two to three months prior to the South African Championships.

The under 15 South African

Championships are held in March/April, the under 19 South African Championships at the beginning of July, and the under 17 South African Championships at the end of September/beginning of October of each year.

Young players are who are willing and good enough for their

provincial teams can play in more than one South African Championship. The national junior squad is selected at the beginning of the year (based on the previous year’s results), and consists of the top eight male and female players in South Africa in the under 19 age group category. Younger players who play in the under 15 and/or under 17 age group categories, who are strong enough to be in the top eight for the under 19 age group category can also be selected for the squad. The squad meets approximately once a month for weekend training sessions. International junior touring teams are selected from this squad. The elite junior players were tested the weekend before the under 19 South African Championships, allowing for a four day rest period before the tournament started. Players in the junior national squad came from the Kwa-Zulu Natal, Western Province, Free State and Gauteng provinces and underwent the fitness testing at the RAU Centre for Sport Science and Biokinetics at the end of June 2002. Individual feedback reports regarding the results of the fitness tests were given to each subject after the results were finalised, and a group report of the results of the fitness tests was given to the coaches of the elite junior badminton squad. Badminton South Africa received results of the testing as well as the results of the research.

CHAPTER TWO:

2.1

LITERATURE REVIEW

INTRODUCTION

The superior performance of today’s athletes is the result of a complex blend of many factors (MacDougall et al., 1991). These factors include genetic endowment, physiology, biomechanics, training, health status, and experience. Champion athletes, depending on their specific sports, vary considerably in their physiological attributes (Daniels, 1974). It is therefore necessary to gain an understanding of the essential performance characteristics important to a specific sport, in order to develop optimal training strategies for the athlete. Achievement of a high skill level for any sport requires a combination of hard work, repetition and practice (Ellenbecker, 1991). badminton is no exception.

The game of

Badminton is a very versatile game that

makes enormous physical, psychological, technical and tactical demands, but it is the physical fitness component that will directly determine the level of demand that can be put on the technical, tactical and psychological abilities of a player (Omosegaard, 1996).

2.2

PHYSICAL CHARACTERISTICS

2.2.1 Introduction

Upon first impressions, badminton is a highly explosive sport, involving a unique movement technique over a relatively small court area (Hughes, 1995).

It is an intermittent sport characterised by long bouts of high

intensity exercise interspersed with rest periods (Faccini and DalMonte, 1996), and entails vigorous movement of both the lower and upper body musculature (Reilly et al., 1990). It requires quick sprints, stops, starts, lunges, jumps, rapid changes of direction, twisting, stretching, smashing, clearing, dropping, and tactically trying to outmaneuver the opponent. The sport demands quick anticipation and response to movements of the opponent, the shuttle, footwork and stroke production (Mahoney and Sharp, 1995). According to Groppel and Roetert (1992) and Lei et al. (1993), the physical requirements of racquet sports demand efficiency in a number of fitness components. To be able to execute advanced strokes or compete effectively against progressively stronger opponents, a player would need to develop higher levels of the basic physical qualities, such as strength, power, muscular endurance, flexibility, coordination and agility.

Body

composition is also important to the game of badminton as excess fat is disadvantageous in moving quickly across court and in leaping to hit the shuttle (Reilly et al., 1990).

According to Omosegaard (1996), the most important physical demands badminton places on its participants are that of aerobic power, maximum concentric and eccentric strength of the hip, knee and ankle extensors, explosive strength and endurance of the hip, knee and ankle extensors as well as explosive and speed strength of the stroke arm.

Maximum

strength and endurance of the trunk, maximum concentric strength and endurance of the stroke arm and flexibility of the hip and hamstrings are not as important.

The least important physical demands badminton

places on its participants are that of lactic acid tolerance, maximum eccentric strength of the stroke arm, and flexibility of the stroke arm. The physical fitness components that will be discussed in the following chapters include body composition, metabolism, muscular characteristics, speed, flexibility and agility.

2.2.2 Body composition

Body composition is an important aspect of fitness (Reilly et al., 1990), and can be predicted from anthropometric measures (Maud and Foster, 1995).

According to Maud and Foster (1995), anthropometry is the

science that deals with the measurement of size, weight, and proportions of the human body, as body size and proportions, physique, and body composition are important factors in physical performance and fitness. A standard anthropometrical analysis during a physical fitness assessment would involve determining the height, mass, somatotype and body fat percentage of an individual or athlete (Maud and Foster, 1995).

Height does not seem to be a determinant of success in badminton (Reilly et al., 1990), as most adult players are taller than the top of the badminton net which is 1.52 to 1.55 metres from the floor. Body mass is a factor that plays a role in influencing performance in throwing sports, and because it can impose resistance to movement, it is also an important factor in contact sports. In sports where body weight has to be lifted repeatedly against gravity, such as in badminton, extra mass in the form of fat would be disadvantageous (Reilly et al., 1990). The physique of an athlete is the configuration or build of the entire body, and the assessment of the physique is most often expressed in the context of somatotype (Maud and Foster, 1995). The somatotype is a composite of the contributions of three components: endomorphy (relative fatness),

mesomorphy

(relative

musculoskeletal

robustness),

and

ectomorphy (relative linearity) (MacDougall et al., 1991 and Maud and Foster, 1995). Body fat percentage is a key component of an individual’s health and physical fitness profile (Heyward, 1998).

It is an important aspect of

fitness as superfluous body fat acts as dead weight in activities where body mass must be lifted repeatedly against gravity in movement during exercise (Reilly et al., 1990), and a high percentage body fat is detrimental in terms of performance as fat cells are not the primary source of energy production, yet energy is required to move the excess mass around the court (Elliot et al., 1989 and Chin et al., 1995).

It has been well established that excess body fat is detrimental to health and that the body fat percentage required for excellence in performance differs between males and females, and varies from sport to sport (Powers and Howley, 1997). Junior males differ from females in many morphological and physiological characteristics, and it is therefore important

consider

the

sexes

separately

data

analysis

(Marshall, 1978). Top competitive players tend to have a low body fat percentage, as the negative impact of excess body fat would increase the energy expended in moving around the court (Elliot et al., 1989 and Chin et al., 1995). Lower levels of body fat will enhance the game of badminton as it permits a more effective gradient for the rapid transfer of heat produced during high intensity exercise, and would be advantageous with regards to moving quickly across the court and in leaping to strike the shuttle. In research performed on junior male and female tennis players by Elliot et al. (1990), body composition was found to be an important indicator of tennis performance for 11 - 15 year old male and female players. In studies performed on American footballers by Wilmore and Haskell (1972), it was concluded that lean body mass rather than total body weight was the critical factor relative to performance ability. Body fat percentage data for badminton players tends to be scarce, especially for junior players. Reilly et al. (1990), Faccini and DalMonte (1996) and Majumdar et al. (1997) recorded relatively low average body fat percentages for national and international male badminton players respectively. The body fat percentages obtained from racquetball studies by Pipes (1979), Plowman and Smith (1997) and Powers and Howley (1997) are also relatively low. Low body fat percentage values have also been

recorded

for

squash

players

studies

performed

Chin et al. (1995).

According to Jaski and Bale (1987), a moderate increase in lean body mass will result in greater speed, strength and power without a loss of flexibility and agility.

2.3

METABOLISM

2.3.1 Introduction

Elite badminton requires a combination of aerobic and anaerobic energy systems, and the involvement of these systems depends on the intensity of the rally and the duration of the match (Dewney and Brodie, 1980). According to Reilly et al. (1990), badminton players are engaged in rallies for approximately half of the playing time. A three game match lasts an average of 36 – 45 minutes, depending on pauses and interruptions, the level of equality between the players, and the number of sets played (Omosegaard, 1996). The average length of a rally is 4.2 - 5.1 seconds, depending on the skill level of the player. In a three game match of international status, a match can last from fourty minutes to one hour (Chin et al., 1995).

Rest periods average 9.3 seconds for singles,

doubles and mixed play. Film analysis studies performed by Faccini and DalMonte (1996) showed that the average duration of a set was 10.4 minutes, and that the average length of a rally was 7.4 seconds. Docherty (1982) reported durations of 4.9, 4.2 and 4.9 seconds per rally of badminton players of low, medium and high skill levels respectively.

The average work:rest ratio of badminton is 1:1 (Omosegaard, 1996), which is the same as that of squash (Montpetit, 1990) and handball (Alexander and Boreski, 1989). Ninety percent of the energy demands associated with the repeated bursts of intense, brief activity are met by the anaerobic processes, but it is the aerobic metabolism that supplies the energy to enable the player to last for the duration of the match. It has been estimated that 60 - 70% of the energy during badminton is derived aerobically and 30% anaerobically (Chin et al., 1995).

2.3.2 Aerobic metabolism

Cardiorespiratory endurance is described by ACSM (1995) as the ability to perform dynamic exercise involving large muscle groups at moderate to high intensity for prolonged periods of time. Simply stated, it is the ability of the body to take up, transport and utilise oxygen efficiently (Sharkey, 1997). A well conditioned heart and an efficient respiratory system are essential for high levels of aerobic fitness, as it means that the systems will be able to adjust and recover quicker from the effects of exercise and work. Aerobic fitness can be influenced by factors such as heredity, training, age, gender and body fat (Sharkey, 1997), as well as heart size and red blood cell concentration (Noble, 1986). It has been established that 93% of an individual’s aerobic power is due to genetic influences, and that, although aerobic power is trainable, there is a genetic ceiling on improvement (Noble, 1986), namely between 5 - 30% (Withers et al., 2000).

The term aerobic power or maximal oxygen consumption is synonymous with VO2 max, and is a component of cardiorespiratory endurance. It refers to the maximal amount of oxygen that can be transported and utilised by the body to produce energy aerobically while breathing air during heavy exercise. It reflects the capacity of the heart, lungs and blood in transporting oxygen to the working muscles as well as the utilization of oxygen by muscles during exercise (Heyward, 1998), and is a good indicator of aerobic fitness. An athlete’s VO2max is important as it theoretically sets the upper limit on endurance performance (Reilly et al., 1990; Maud and Foster, 1995; Reilly and Stratton, 1995 and Plowman and Smith, 1997). The absolute power of the aerobic system (VO2max) is expressed as volume (litres) per unit of time (minutes).

However, when making comparisons between

athletes, one needs to take the amount of tissue that needs to be supplied, i.e. body weight, into account.

This will then give a good

indication of the relative VO2max value of an athlete, and is expressed as mlO2.kg-1.min-1. Female athletes tend to have smaller VO2max values compared to males (Noakes, 1986; Maud and Foster, 1995; Omosegaard, 1996; Plowman and Smith, 1997 and Withers et al., 2000) due to higher body fat content, smaller muscle mass (Noakes, 1986) and lower hemoglobin content. A female’s blood consists of 13g hemoglobin per 100ml, compared to 15g per 100ml in men (Omosegaard, 1996). Relative values for males tend to be 20 - 30% higher than females (Plowman and Smith, 1997). Aerobic power tends to decrease with age (Withers et al., 2000). However, a child’s ability to take in and utilise oxygen improves as a result of dimensional and maturational changes (Plowman and Smith, 1997), such as an increase in body size, haemoglobin concentration and lean body mass (Reilly and Stratton, 1995).

The rate of improvement remains relatively constant between 6 and 18 years for boys, and tends to decrease in girls between adolescence and adulthood. This is due to structural changes in skeletal proportions and a relatively large increase in adipose tissue.

In general, endurance

performance improves progressively throughout childhood until puberty; but directly determined VO2max does not (Plowman and Smith, 1997). Expressed in relative terms, values in children are similar to values in the adolescent and adult male. Central and peripheral circulatory factors are the main factors that limit aerobic power of athletes (Noakes, 1986 and Plowman and Smith, 1997). Haemoglobin concentration is one such circulatory factor as it affects the amount of oxygen carried in the blood. The next factor that limits aerobic power is that of cardiac output, which is the rate at which the blood carrying the oxygen is transported to the active muscles involved in exercise (Noakes, 1986).

According to Plowman and Smith (1997),

aerobic power is limited more by the cardiovascular system’s ability to deliver the oxygen than by the muscles’ ability to use it. The greatest VO2max values are typically found in endurance sports such as long distance running and cross-country skiing and are due to a combination of genetic endowment and training (Withers et al., 2000). Athletes whose performance depends on the ability of the cardiovascular system to sustain dynamic exercise consistently, tend to have higher VO2max values than athletes whose performance is based mostly on motor skills.

Maximal oxygen consumption values obtained from research on top international badminton players are relatively high and vary from 55.7 – 73.0 mlO2.kg-1.min-1 (Mikkelsen, 1979; Chin et al., 1995; Faccini and DalMonte, 1996; Omosegaard, 1996 and Majumdar et al., 1997), whereas the average range for elite handball players is from 50 - 65 mlO2.kg-1.min-1 (Alexander and Boreski, 1989; Loftin et al., 1996 and Rannou et al., 2001).

The average range for squash players is from

-1

51.0 - 65.7 mlO2.kg .min-1 (Van Rensburg et al., 1982; Steininger and Wodick, 1987; Reilly et al., 1990 and Todd and Mahoney, 1995). In studies performed by Larsson (1999) on elite male badminton players, oxygen uptake measured in a singles game increased during the match, reaching a value of 86% of the predetermined VO2max in the laboratory. Badminton players studied by Daniels (1974) were found to be competing at 100% of their VO2max. These values correspond with Omosegaard (1996) stating that the workload during a singles match is 80 - 100% of VO2max. Younger players however, do not necessarily operate at a high relative loading. It was found that the proportionate loading of the oxygen transport system was 52% of the VO2max, which is enough to place a moderate strain on the aerobic mechanisms (Reilly et al., 1990).

studies performed by Majumdar et al. (1997) of national male badminton players, the mean VO2max values during a game were found to be at 57% of the VO2max. Mean and maximum values of oxygen consumption during a game recorded by Faccini and DalMonte (1996) were that of 60.4% and 85.0% respectively. The aerobic component of badminton is underlined by studies investigating the capillary supply per muscle fibre, which showed that the leg muscles of top badminton players had muscle fibre types that tended towards those found in endurance athletes (Reilly et al., 1990).

According to Reilly et al. (1990), muscle samples of the vastus lateralis showed high succynile dehydrogenase activity, indicating an aerobic adaptation in the muscles of the legs. These values however, were well below values of top distance runners. In studies by Mikkelson (1979), it was found that muscle hypertrophy was most pronounced in the slow twitch fibres, which were 8% larger than the FTa fibres and 18% larger than the FTb fibres. In research performed by Omosegaard (1996) it was found that the average proportion of ST fibres in men is 62% and in women is 56%, which also reflects the aerobic demands of badminton. Studies performed by Mikkelsen (1979) looked at glycogen depletion in the legs during a game of badminton. The results showed that both the ST and FTa fibres were active, although it was the ST fibres that were primarily active.

The better supply of capillaries, higher succynile

dehydrogenase activity, ST and FTa:FTb fibre ratio of the right leg, and glycogen depletion in the legs, all prove the aerobic demand of badminton. Despite the stop-and-start nature of the game, badminton has a high aerobic component due to the fact that the high-energy phosphates used for the immediate energy requirements of muscles are predominantly resynthesized by oxidation during recovery periods without essential conversion of pyruvate to lactate. According to Hughes (1995), myoglobin has a vital role in providing the energy in badminton, as it can act as a short term supplier of oxygen molecules to the mitochondria in the working muscle groups, particularly at the onset of activity. The aerobic system is also instrumental in delaying the increase in blood lactate as well as in its removal. This corresponds with low blood lactate values found in research performed by Faccini and DalMonte (1996) and Majumdar et al. (1997), who found that no significant changes occurred in the blood lactate levels as the match progressed.

In Chin et al. (1995), it was noted that blood lactate values during a game ranged from 3.0 – 5.7 mmol/lt and that the low values may be due to the light muscle group work and the light racquet involved in badminton. However, even though the average concentration of lactic acid is rather low, there is a great demand on the ability to tolerate high concentrations of lactic acid for short periods of time

2.3.3 Anaerobic metabolism

There is a low contribution from the anaerobic system in supplying the necessary energy in badminton (Hughes, 1995). According to Chin et al. (1995), approximately 30% of the energy during badminton is derived anaerobically. Although the anaerobic energy contribution in badminton is low, there is a great demand on the player’s ability to tolerate high anaerobic activity for short periods of time. This is due to the fact that the rallies during a game are a mixture of push-offs, direction changes, smashes, waiting for the shuttle, walks, runs and jumps. This type of activity activates the ATP-PC system. During an average rally of 10 seconds, the ATP-PC system is depleted after 5 - 6 seconds, thereafter which the lactic acid system takes over the production of energy. The duration of work however is so short that only small amounts of lactic acid is formed, and these amounts are cleared during the recovery periods (Hughes, 1995 and Omosegaard, 1996). Antonutto and Prampero (1995) concluded that if the blood lactate concentration does not increase constantly in time, the energy for muscular work is derived entirely from aerobic sources, even if the lactate concentration in the blood is higher than the resting value.

According to Reilly and Stratton (1995), children have smaller muscle glycogen stores and a relatively poor anaerobic capacity.

The poor

anaerobic capacity is reflected in lower levels of lactate production during intense exercise bouts which is suggestive of a low glycolytic rate. The anaerobic threshold of children, as determined by the 4mmol/lt. whole blood lactate level, does not occur until approximately 90% of the peak VO2max compared to 70% in adults. The ability to recover is an important aspect of fitness. In the recovery periods the stores of ATP-PC in the cells are being replenished for the next burst of activity.

The ability to recover more completely during

recovery periods should ensure the ability to maintain higher levels of activity during each rally as there is a greater replenishment of energy stores during the game (Alexander and Boreski, 1989). The advantage of having a high aerobic power is that it would enable the player to both force a more intensive pace of play against a less fit opponent, and endure the intensity and length of matches more comfortably (Reilly et al., 1990).

2.4

MUSCULAR CHARACTERISTICS

2.4.1 Introduction

Many sports require a generation of high forces and power outputs (Reilly et al., 1990). It is the muscles’ ability to develop tension that forms the basis for all types of movement in sport (Omosegaard, 1996). Omosegaard (1996) was able to measure the velocities and accelerations that are typical of each stage of play in badminton by analysis of highspeed camera recordings.

It was found that the acceleration during

braking and push-offs is due to muscle power, and that footwork at the playing centre and hitting the shuttle required muscle strength, while movements to and from the shuttle required speed. The repeated pushoffs in the corners and playing centre put a big demand on a specific kind of dynamic endurance.

Eccentric strength is also important as it is

involved in braking when landing and in pushing-off towards the playing centre. Badminton at the highest level places a great demand on leg and back strength, leg endurance as well as explosive power (Omosegaard, 1996).

2.4.2 Strength

Muscular strength can be defined as the peak torque or force developed during a maximal voluntary contraction, under a given set of conditions (MacDougall et al., 1991).

Muscular strength is a relative factor related to the demand of the activity (McGlynn, 1996), and is important in sports requiring the lifting, carrying or throwing of body weight or external weights (Sharkey, 1986). According to Omosegaard (1996), the strength of a muscle that can be developed, depends mostly on the joints and muscles involved in the movement, the range of movement, the ability of the nervous system in activating the right muscle fibres at the right points in time and the speed of the movement. The greatest strength is produced during fast eccentric contractions, whereas the opposite is true for concentric contractions as the faster a muscle contracts concentrically, the less force it can produce (Reilly et al., 1990 and Omosegaard, 1996). Badminton is a sport that is strength-related, rather than strength-limited in that the performance of a player is influenced by strength, not limited by it (Wrigley and Strauss, 2000).

2.4.2.1 Leg strength

Badminton at the highest level puts a great demand on leg strength and endurance (Omosegaard, 1996).

The muscle strength during a

movement varies during the range of movement due to muscular and mechanical conditions. Normally, the more a muscle is stretched, the more tension it can produce. Muscle fibres can be described by two characteristics namely their contractile properties and metabolic properties (Plowman and Smith, 1997).

With regards to contractile properties, muscle fibres can be classified as Type I (slow twitch) or Type 2 (fast twitch) with varying subclassifications of the fast twitch fibre (Perrin, 1993). According to Perrin (1993), short twitch fibres have motor units that are activated at lower thresholds and they have low conduction velocities and long contraction times. The short twitch fibres are therefore specialised for usage with low velocity activities, and they rely mostly on oxidative metabolism to produce energy. Fast twitch fibres are activated at high thresholds and have high conduction velocities and short contraction times. These fibres are specialised for high power outputs and high velocities for short periods of time, and they have the ability to work under both oxidative and glycolytic conditions. As a result, the recruitment of the different fibre types depends on the tension requirements of any muscular contraction. Due to the fact that slow twitch fibres have a lower threshold for activation, they are recruited first. The fast twitch fibres are then recruited if the tension required for movement increases. With regards to the metabolic properties, human muscle fibres can be described as glycolytic, oxidative, or a combination of both. Glycolytic muscle fibres are able to produce energy anaerobically, and oxidative fibres produce energy aerobically. The muscle fibres in a human have the ability to produce energy by both glycolytic and oxidative processes, but one or the other may predominate or the production may be balanced. The slow twitch fibres rely primarily on oxidative metabolism, and hence are referred to as slow oxidative fibres. Fast twitch fibres that perform predominantly under glycolytic conditions are referred to as fast glycolytic fibres, and the fast twitch fibres that perform under both oxidative and glycolytic conditions are referred to as fast oxidative glycolytic fibres (Plowman and Smith, 1997).

Research results from Reilly et al. (1990), indicated that muscle hypertrophy was most pronounced in the slow twitch fibres, which were 8% larger than the FTa, and 18% larger than FTb fibres. It was found that ST fibres constituted 62% of the total number of muscle fibres in the vastus lateralis muscle of the male player, and 56% of the same muscle in the female players (Omosegaard, 1996).

The muscle fibres of elite

badminton players also tend to be large with a high capillary density (Chin et al., 1995). Leg strength values measured of world class badminton players are quite impressive (Reilly et al., 1990), as the relative leg strength values obtained in the study were higher than values obtained from tennis and handball players. In a study performed on elite Danish badminton players in connection with the project OG92 (Olympic Games 1992) by the Danish Badminton Federation (Omosegaard, 1996), it was found that badminton players have strong knee, hip and ankle extensors, but that the strength in the hamstrings was not proportionately developed. This resulted in the hamstring:quadriceps ratio of the players being quite low, which in turn results in an increased risk of knee injuries. Studies performed by Mikkelsen (1979), on top Danish and Dutch players showed that the muscle hypertrophy of badminton players tended to be unilaterally biased, with the right calves and thighs of the right handed players being significantly bigger. This, according to Reilly et al. (1990), is due to the use of the preferred leg in generating force against the ground in the step prior to hitting the shuttle. Other reasons for the right leg being significantly bigger than the left (for right handed players) is that 80 - 90% of all “braking” in the corners are done on the right leg, the right leg is almost always used in the lunge jump, it is used in all net returns, and is used in situations under pressure anywhere on the court (Omosegaard, 1996).

The demands of aerobic endurance as well as leg strength are greater on the right leg than on the left (for a right-handed player). The opposite would be true for left handed players (Omosegaard, 1996).

2.4.2.2 Arm strength

The important muscle groups of the arm for badminton are the rotator muscles of the shoulder joint, the under arm rotators, the arm extensors and the shoulder muscles which lead the upper arm forward-upwards, and backwards – upwards. According to Ellenbecker (1992), isokinetic data on the shoulder can be used to formulate unilateral ratios and can be used to determine muscle imbalances surrounding a joint. In a study performed on elite Danish badminton players it was found that the front muscles of the shoulder girdle were disproportionately much stronger than the muscles on the back of the shoulder girdle. This is due to the fact that the overhead forehand strokes are performed much more than the overhead backhand strokes.

According to Chandler et al. (1992), increased strength in

internal rotation may occur in sports where “plyometric-type” movements are used during the acceleration phase, such as in badminton. It was found that the increases in internal rotation strength and power was as a result of adaptation to the stroke motions. In studies performed by Perrin (1993) it was found that athletes in bilaterally asymmetrical upper extremity activities, such as racquet sports, may have up to 15% greater muscular strength of the dominant arm compared to the non-dominant arm.

In studies performed by Omosegaard (1996), it was found that the stroke arm was more powerful than the opposite arm with a difference in the circumference in both the lower and upper arm of approximately 10%. This has also been true for results found in studies performed on tennis players. It was found that the dominant arm was significantly stronger than the non-dominant arm, and that the inward rotators were significantly stronger than the external rotators. In healthy adults, the ratio should be 3:2 for shoulder internal rotation:shoulder external rotation (Ellenbecker, 1992). Overall, the muscle strength of the arm is not an important requirement for badminton because the forces required in hitting the shuttle are not great (Reilly et al., 1990 and Omosegaard, 1996). This is due to the fact that the resistance to the stroke of the movement is small (a racquet weighs approximately 100g and the shuttle is very light), and the smaller the resistance to movement, the less maximal muscle strength matters to the speed of the movement (Omosegaard, 1996). According to Groppel and Roetert (1992), the upper body can be strong enough simply from the nature of the sport. In a study on handball players by Bayios et al. (2001), it was found that the peak torque of the internal and external rotators was generally not related to the ball velocity, so increasing peak strength would not result in an increase in the ball velocity when thrown. Speed strength in the context of badminton refers to strength in fast movements with less resistance (Omosegaard, 1996). Speed strength is a descriptive term encompassing two types of strength, namely starting strength and explosive strength. Starting strength refers to the ability of an athlete to recruit as many muscle fibers as possible instantaneously, and explosive strength refers to the ability to keep these recruited fibers active for a measurable period of time (Sutton, unpublished work).

According to Omosegaard (1996), the speed strength of the rotator muscles of the shoulder is a more important component than absolute strength as it is essential to hit through the shuttle quickly and effortlessly. Although the maximum muscular strength of the arm is not an important requirement for the badminton player, it does have its part to play. Absolute strength is necessary for situations where only the arm muscles need to be used instead of an integration of body muscles (Omosegaard, 1996), such as in the backhand clear, or a “desperation or out of position” shot.

In the backhand clear, only the shoulder and stroke arm can

contribute to the speed of the racquet, whereas in the forehand upperhand stroke, the whole body movement can assist the movement of the stroke. In desperation shots, when a player wishes to hit as hard as possible, there isn’t any time to perform the ideal stroke movement with pre-loading and by using many muscle groups and a long range of movement.

In these situations, the strength of the stroke will mostly

depend on the shoulder and under arm rotators to accelerate the racquet from zero speed. The arm extensors and inward rotators of the shoulder and lower arm are capable of an acceleration of the racquet head of approximately 50 - 180km/hr in approximately 0.08 seconds (Omosegaard, 1996). This means that the muscular tension in the pre-loading eccentric contraction, and in the following dynamic contraction, must therefore be considerable. The posterior rotator cuff plays an important role in decelerating and stabilising the humerus during the follow-through for stroke production, and the external rotation strength is important for glenohumeral joint stability (Chandler et al., 1992; Ellenbecker, 1992; and Bayios et al., 2001).

The deceleration of the arm involves eccentric muscle

contractions of the posterior shoulder musculature (Chandler et al., 1992).

Speed strength, explosive strength and to some extent, maximum muscular strength are important for the arm muscles in badminton (Omosegaard, 1996).

2.4.2.3 Abdominal and back strength

Well developed strength of the muscles controlling the trunk is important in many sport contexts as most sports encompass relatively large movements of the trunk (Andersson et al., 1988). The abdominal and back muscles are important muscles for badminton as they are involved in virtually everything that takes place on a badminton court (Omosegaard, 1996).

According to Roetert et al. (1996), trunk

muscles are considered a vital link in the kinetic chain of the body, and without sufficient trunk development, strokes will lack power and control. This is due to the fact that most strokes are the result of a successive summation of forces. This summation of forces involves a transferring of ground reaction forces up through the legs, hips, trunk and arm. Since the body is interconnected from head to toe through the muscular system, the trunk muscles play an equally important role as the arms and legs in stroke production.

Since the trunk segment has a large mass, great

demands are exerted on the musculature, particularly if the trunk movements are to be performed with high accelerations (Andersson et al., 1988).

Badminton consists of combined jerky movements such as simultaneous rotation and lateral trunk flexion, and movements to the outer positions of the spine (Omosegaard, 1996).

The abdominal and back muscles

perform an important stabilising and balancing function for all braking and push-offs, as they condition the work of the leg muscles: partly by providing a firm base for the work of the hip and thigh muscles, and partly by transferring the work to the rest of the body. The trunk muscles are also directly involved with stroke production, as the trunk provides the firm base necessary for the work of the arm and shoulder muscles (Omosegaard, 1996). According to Omosegaard (1996), demands are placed on the dynamic strength and endurance of the back and abdominal muscles in connection with flexion and extension, lateral flexion and rotation of the spine.

2.4.3 Power

Coaches, trainers, and athletes are continually searching for optimum ways of identifying key elements that contribute to athletic performance. Muscular power or explosive strength is one such element, and the ability to generate great amounts of power is recognized as a primary factor in athletic success (Beckenholdt and Mayhew, 1983).

According to

MacDougall et al. (1991), the relevance and relative importance of power in sport performance will vary according to the different requirements of the sport.

Power is a term used to describe the amount of work (the product of force and distance) done per unit of time (MacDougall et al., 1991; Groppel and Roetert, 1992; Shephard and Astrand, 1992; Perrin, 1993; Maud and Foster, 1995 and Powers and Howley, 1997), and is a combination of strength and speed. According to Roetert et al. (1996), a vital aspect of sports such as tennis and badminton is the ability of the player to exert muscular force at a high speed. A high level of strength and power will allow a player to accelerate the body over the court, and an increase in either strength or speed will lead to an increase in power.

Body

composition and strength are major factors in the ability of an individual to generate power in a relatively short period of time (Mayhew et al., 1994). Strength only plays a minor role unless it can be applied explosively over a short period of time. According to Beckenholdt and Mayhew (1983), explosive power is the power developed with rapid, vigorous body movement from a stationary position or with a short running approach.

Explosive muscle strength

defined by Agard (1999) is the steep initial increase in muscle contractile force exerted within the first 30 - 200 milliseconds of contraction.

requires both co-ordination and strength (Omosegaard, 1996), and refers to the ability to perform a movement of great resistance as quickly as possible.

Nearly all explosive movements in badminton start with an

eccentric pre-loading counter movement whereby the developed strength is improved dramatically (Omosegaard, 1996).

Pre-loading is the

mechanism where coordination, muscle strength and energy consumption are at their optimal due to the utilization of the body’s reflexes, joint angles, muscle lengths and physical properties. According to Sharkey (1997), a muscle exerts more force when it is stretched just before contraction in a pre-loading movement. This pre-loading stretch aligns the cross bridges in the muscles for maximal force, takes the slack out of the system, and stores elastic energy in the muscle.

When the pre-load is performed properly, it can contribute to the power and efficiency of movement. Leg power is an important component in badminton in that it results in the player being able to move quickly and explosively to the shuttle in various directions and to jump high to play overhead strokes. Greater leg power results in a greater acceleration and faster speed when lifting off the floor when moving, or jumping to the shuttle.

According to Omosegaard

(1996), an explosive player will typically be able to jump high, change direction quickly and will generally appear to be swift and mobile on the badminton court. Leg power is therefore a combination of coordination and muscular properties. Whereas speed strength of the rotator muscles of the shoulder is the most important characteristic needed for striking the shuttle, power is an important component for the arm muscles. Hitting with power means that the badminton player must optimise the action between the larger body parts to hit a high velocity and still allow the upper limb to maintain good control over the racquet (Groppel and Roetert, 1992).

2.4.4 Muscular endurance

Muscular endurance is the ability of a muscle group to execute repeated contractions of submaximal resistance, over a period of sufficient time to cause muscular fatigue, or to statically maintain a specific percentage of maximal voluntary contraction for a prolonged period of time (Luttgens et al., 1992 and ACSM, 1995).

It suggests something about an individual’s ability to perform muscular work for short or long periods of time (Omosegaard, 1996), and the ability of the individual to resist fatigue (Shephard and Astrand, 1992). In research performed on cyclists by Hickson et al. (1980), it was shown that resistance training might improve muscular endurance.

Muscular

endurance is to some degree dependant on muscular strength. However, it is possible to have high levels of muscle strength and low levels of muscle endurance (McGlynn, 1996). A stronger athlete will have greater absolute endurance with heavy loads, but less relative endurance (MacDougall et al., 1991). According to Noble (1986) and Shephard and Astrand (1992), endurance athletes are more likely to have primarily ST fibres, and the performance would depend on the ability to supply the ative muscles with adequate amounts of oxygen and essential nutrients. Endurance is involved to some extent in badminton due to the fact that ST fibres were found in the vastus lateralis muscles of badminton players. The repeated push-offs in the corners and playing center, places great demands on the dynamic endurance of the leg muscles of badminton players (Omosegaard, 1996). In studies performed on badminton it was found that there are approximately 70 rallies played in an even singles game, where each player returns the shuttlecock about 3.6 times per rally, and each return consists of one push-off in the centre of the court and one in the corner. This means that each player pushes off about 500 times in a game. (Omosegaard, 1996). Dynamic endurance of the arm muscles is also an important characteristic for badminton due to the repetitive movements of the arm at high speeds.

2.5

SPEED

Speed is needed in badminton in moving to and from the shuttle. Speed on a badminton court is not only a question of being in good physical condition or following the right tactics, but is a combination of technique, tactics, physique and mental frame of mind (Omosegaard, 1996). Running speed and agility are very important to the badminton player due to the need for speed variation, height and angle of approach to the shuttle. The ability to cover short distances quickly will also be of great advantage to the badminton player (Todd and Mahoney, 1995). Due to the nature of the game and the size of the court, it is important for the badminton player to reach his/her maximum speed as fast as possible. The speed on court has been measured to be approximately 70 - 85% of an individuals’ maximum speed, which is fairly low. Results from tests based on speed on a badminton court, show that the average speed during rallies is approximately 6.3km/hr. The speed on court is generally faster going to the shuttlecock (6.8km/hr) than when returning to the playing centre (5.5km/hr), with the highest speed being 14.0km/hr (Omosegaard, 1996). In studies performed by Wirhed et al. (1983), it was found that the main difference between the fast Asian players and the slower European players was the braking time in the corners. It was found that the Asian players used less time in braking, which is indicative of a greater maximum eccentric strength.

A greater eccentric strength of the legs

could therefore improve a player’s speed on court.

Footwork technique is as important to speed as the stroke technique is to the power of strokes. It is necessary in order to benefit from the physical fitness obtained during training, as incorrect footwork will limit and slow down movement on the court. With regard to tactics in badminton, many players choose tactics that do not permit the player to benefit from his/her speed. Attacking tactics often bring out the speed in a player whereas a defensive approach has the tendency to slow the tempo of the game, and with it the speed of the player. In this respect, habits regarding tactics and technique are closely linked (Omosegaard, 1996). Anticipation also plays a role in a player’s speed on the court, as it is the time spent moving from the playing centre to the area where the opponent has played the shuttle. This is equivalent to the time spent perceiving where the shuttlecock is played, as well as the time spent by the player in travelling to the area where the shuttle was played.

2.6

FLEXIBILITY

Flexibility is an important, yet often neglected component of physical fitness (Heyward, 1998). It is important not only in learning athletic skills satisfactorily, but also for general health and fitness (McGlynn, 1996), athletic performance, injury prevention, and rehabilitation (MacDougall et al., 1991).

It is a component of fitness that sport scientists and

physiotherapists measure to gain an impression of a person’s physical capacity (Harvey and Mansfield, 2000).

Flexibility reflects the ability of the muscle-tendon units to elongate within the physical limitations imposed by the joint (MacDougall et al., 1991), and refers to the looseness or suppleness of a joint. According to Maud and Foster (1995) and Heyward (1998), there are two types of flexibility namely static and dynamic flexibility. Static flexibility is the measure of the total range of motion at a joint whereas dynamic flexibility refers to the measure of the resistance to movement. Flexibility however, is not only specific to the sport, but also to the joint and joint action (MacDougall et al., 1991). Joint flexibility is controlled by a number of morphological factors such as the geometry of the joint capsule, adipose tissue, the muscles surrounding the joint, the tendons and ligaments around the joint, and the skin (Maud and Foster, 1995). The joint capsule contributes to approximately 47% of the ROM (range of motion), the muscles approximately 41%, the tendons approximately 10%, and the skin approximately 2% (McGlynn, 1996). Due to the joint capsule being rigid, when attempting to increase flexibility, the emphasis of stretching is placed on the muscle and skin tissue. The joint structure has an influence on flexibility in that it determines the planes of motion and may limit the ROM at a given joint. Triaxial joints tend to afford a greater degree of movement in more directions than uniaxial or biaxial joints. Other factors that may affect flexibility, besides joint and musculature structures, include age, sex, body type, exercise intensity, and the presence of disorders (MacDougall et al., 1991). Research on these factors, however, does not show conclusive evidence that these factors have causal effects on flexibility. Temperature has also been known to have an influence on flexibility in that it results in the muscle tissue becoming more compliant and elastic.

Within the realm of sport, there are many activities where high degrees of flexibility in specific joints are desireable for enhanced performance in both quantitative and qualitative athletic activities (Maud and Foster, 1995).

The degree of relevant importance of flexibility, however, is

specific to the sport and can be ascertained by observing skills and movement patterns associated with the different sports.

According to

MacDougall et al. (1991), flexibility is relevant to jumping, swimming, racquet sports and most team sports. It is highly relevant to sports such as figure skating, gymnastics and diving and less relevant to sports such as boxing, long distance running, archery, shooting, curling and cycling. It is an advantage to have above average flexibility levels of the trunk and shoulder regions for racquet sports (Chin et al., 1995). This corresponds with Omosegaard (1996) who states that a greater flexibility of the trunk and stroke arm is undoubtedly an important factor, as well as hip and hamstring flexibility. Therefore, with badminton, above average flexibility of the shoulder, trunk and hip is expected of players, as flexibility is important in reaching the shuttlecock, especially in stressful situations. An adequate level of flexibility also allows a player to perform the various strokes efficiently as many retrievals are made with the spine and shoulder joint in hyperextension, and with the hip and hamstrings fully flexed when lunge jumps are made at the net. This flexibility allows for more fluent stroking when forced to stretch (Elliot et al., 1989) and facilitates agility on the court (Reilly et al., 1990). Omosegaard (1996) recorded that most right handed badminton players have a reduced flexibility of the right hip in comparison to the left hip, which is probably due to greater loads imposed on the right leg during the lunge jump, combined with inadequate stretching exercises. On the other hand, most of the right-handed players have a greater flexibility of the right shoulder for inward rotation than for external rotation.

This could be due to the movements in the shoulder during the smash and clear, when the upper arm passes close by the outer limit of outward rotation of the shoulder.

Unfortunately, specific flexibility data on the

different joints of the badminton player are scarce. According to Chandler et al. (1990), if the normal flexibility of the surrounding tissue of the joint is not maintained, a decrease in joint range of motion could result over a period of time, which in turn may result in uncoordinated or awkward movement, a decreased efficiency, the possibility of injury to ligaments and tendons, poor posture, lower back problems (McGlynn, 1996) as well as a decreased performance. Omosegaard (1996) states that a decrease in the flexibility of one joint can force other joints into their outer positions, which is the weaker state, and can force a player into using wrong stroke technique. A greater flexibility in badminton players would result in improved maximal strength, a greater ability to utilise the stretch-shorten cycles effectively, augmented efficiency and correct movement patterns throughout the required range of motion.

It is for these reasons that flexibility is an

important component of badminton.

2.7

AGILITY

Agility is the physical ability that enables a rapid and precise change of body position and direction (Johnson and Nelson, 1986), without a loss of balance (Sharkey, 1986). The whole body movement can be performed in the horizontal plane, or in the vertical plane (Draper and Lancaster, 2000).

Agility is important for sports requiring rapid and precise changes of direction, and depends on the strength, endurance, speed, balance, visual processing, timing, reaction time, perception, anticipation and skill of the athlete. Agility is crucial to good court movement and correct positioning on the court (Groppel and Roetert, 1992). Correct positioning on the court is essential in order to strike the shuttle effectively, and requires the use of the legs and feet. While the upper extremity uses the racquet to hit the shuttle, the lower extremity is responsible for getting the player in position to use the racquet. Agility is important to the badminton player due to the variation in the speed, height and angle of approach to the shuttle (Todd and Mahoney, 1995). In badminton, the ability to keep one’s balance while hitting a stroke, depends on proper footwork, with an interplay of all the muscles of the body under the guidance of the labyrinth of the inner ear and vision (Izen, 1971). To be fast on a badminton court is not only a question of being in good physical condition or following the right tactics, but also taking into account technique and mental frame of mind (Omosegaard, 1996). Correct footwork technique is needed in order to be able to benefit reasonably from physical abilities gained, and to be able to move quickly and precisely to where the shuttle is, as efficiently as possible. Anticipation is also an important component that needs to be developed, as a badminton player usually has only 1 - 2 seconds to react. This is most apparent in doubles, which is a quicker game. Quick movement on a badminton court will also depend on the acceleration and braking ability of the athlete, which in turn is determined by the leg strength of the player. Aerobic power affects agility in that low oxygen uptake results in an earlier onset of fatigue, which in turn results in the player becoming slower, more quickly. As a result, aerobic and muscular fitness should help maintain agility for extended periods.

CHAPTER THREE:

3.1

METHODOLOGY

SUBJECTS

Eight elite male and seven elite female junior badminton players (age 16 + 1) volunteered, with informed consent, for this study. Each subject who participated in the research was a member of the Junior National Badminton Squad in 2002.

3.2

TRAINING

The subjects continued with their normal training routines during the research period. No alterations were made to any training routines.

3.3

TESTING PROCEDURE

3.3.1 Introduction

The testing procedure was carried out at the peak of the badminton season, a week before the under nineteen Junior South African Championships, when fitness levels were assumed to be at a peak. The tests were carried out over three days, allowing a four day rest period before the tournament. The body composition, flexibility, isokinetic and muscular endurance test protocols were completed in a laboratory at an altitude of 1650m and controlled temperature of 21 - 23 degrees Celsius. The multistage shuttle run test, speed test, agility and explosiveness test protocols however, were not completed in a controlled temperature. All the field tests were performed in badminton apparel.

3.3.2 Anthropometry

Body height was measured to the nearest 0.1cm, body weight to within 0.1g and body fat percentage was calculated on the basis of six skinfolds as stipulated by MOGAP (Carter, 1982). The somatotype was calculated using the Heath-Carter method (Carter, 1980).

3.3.3 Flexibility tests

Flexibility is the ability of a joint, or series of joints, to move fluidly through a full range of motion (Heyward, 1998). There are two types of measures of flexibility known as static and dynamic flexibility. Static flexibility refers to the total range of motion at the joint, whereas dynamic flexibility refers to the measure of the resistance to movement. The flexibility tests in this study were implemented to determine the subjects’ range of movement at specific joints, i.e. the static flexibility.

3.3.3.1

Test protocol

Flexibility was evaluated using a Leighton Flexometer and was measured according to the Leighton flexibility protocol (1987). The preparation for and execution of all measurements was standardized.

In using the

instrument, the Leighton Flexometer was strapped to the segment being tested, with the dial locked in one extreme position (i.e. full flexion of the elbow). The movement was made and the pointer locked at the other extreme position (i.e. the full extension of the elbow). The direct reading of the pointer on the dial was the range of movement that had taken place.

3.3.3.2 Shoulder flexion and extension

The subject stood at the projecting corner of a wall with his/her back to the wall and arms at the side. The shoulder blades, buttocks and heels had to touch the wall and the Leighton Flexometer was placed on the lateral side of the dominant upper arm, midway between the acromiale and radiale. The dominant arm moved forward and upward in an arc as far as possible with the palm facing the wall. When the arm had reached as far as it could, the reading was taken. The same arm then moved downward and backward in an arc as far as possible with the palm sliding against the wall. When the arm had reached as far as it could, the reading was taken. The reading was considered invalid and the measurement repeated if the subject’s heels, buttocks and shoulders lifted off the wall at any stage during the movement, and if the arm being measured was not kept straight. The palm of the hand had to face the wall when the reading was being taken.

3.3.3.3 Shoulder internal and external rotation

The subject was in a supine position on a plynth with the arm to be measured extending sideward at a ninety degree angle to the body with the elbow beyond the edge of the plynth.

The forearm had to be flexed at a ninety degree angle to the upper arm that was lying flat, and the Leighton Flexometer was positioned on the lateral side of the forearm, midway between the radiale and stylion. The internal rotation of the dominant arm was measured as follows: from the starting position and with the dial locked, the forearm moved downward and backward in an arc as far as possible. An assistant held the shoulder down throughout the range of motion so as to prevent the shoulder blades from lifting off the plynth.

When measuring external

rotation, the forearm moved upward and backward in an arc as far as possible. Throughout the range of motion, the upper arm had to be kept parallel to the floor and at a ninety degree angle to the body. When the furthest point was reached for both internal and external rotation, the reading was taken. The reading was considered invalid and was re-measured if the heels, buttocks and shoulders lifted off the plynth at any stage during the movement.

3.3.3.4 Trunk lateral flexion

The subject stood with his/her feet together, knees straight and arms at the sides. The Leighton Flexometer was fastened to the thoracic spine between T5 and T7. From the starting position and with the dial locked the subject had to bend sideward to the left and right as far as possible, taking care not to flex forward through the range of motion. Both feet had to remain flat on the floor and the knees kept straight for the duration of the movement. The reading was taken at the furthest point.

3.3.3.5 Trunk flexion and extension

Trunk flexion The subject was in a supine position on the plynth with both feet held together by an assistant, the knees in full extension and arms folded with hands behind the neck. The Leighton Flexometer was fastened to the right side of the chest at the level of the mesosternale. From the starting position and with the dial locked, the subject sat up and bent his/her trunk towards the knees as far as possible, where the reading was then taken. To determine the trunk flexion score, the hip flexion score was subtracted from the score obtained in this test.

This is due to the fact that the

movement involved both trunk and hip flexion.

Trunk extension The subject was in a prone position on the plynth with his/her legs together in full extension, chin in contact with the plynth, and with both feet extending beyond the edge of the plynth. The legs were held down at the ankle by an assistant and the arms were flexed with the hands placed behind the head. The Leighton Flexometer was fastened to the right side of the chest at the level of the mesosternale. From the starting position, and with the dial locked, the subject extended his/her back raising the shoulders as far as possible, where the reading was then taken.

3.3.3.6 Hip flexion

The subject was in a supine position on the plynth with his/her legs together, knees in full extension, and with the arms resting on the plynth at the side of the body. The Leighton Flexometer was fastened to the lateral side of the leg being measured in a mid-thigh position. From the starting position and with the dial locked, the subject moved the leg upward in an arc to a position as close to the head as possible, making sure to keep the knees fully extended throughout the range of motion. The non-measurement hip was held down at the hip by an assistant to ensure that the hip remained in contact with the plynth through the range of motion. At the maximum stretch, the reading was taken. A reading was considered invalid and re-measured if the subject’s shoulders, hips and heel of the non-measurement leg lifted off the plynth at any stage during the movement.

3.3.3.7 Hip extension

The subject was in a prone position on the plynth with both arms resting on the plynth next to the body with the shoulders, hips and knees in contact with the plynth. The legs were in full extension with both feet extending just beyond the edge of the plynth. The Leighton Flexometer was fastened to the lateral side of the leg being measured in a mid-thigh position.

From the starting position and with the dial locked, the leg was raised upward as far as possible, making sure to keep the knees fully extended throughout the range of motion.

The non-measurement leg was held

down at the ankle by an assistant to ensure that the non-measurement leg remained in contact with the plynth through the range of motion. At the furthest point of the stretch the reading was recorded. A reading was considered invalid and re-measured if the subject’s shoulders, hips and knees of the non-measurement leg lifted off the plynth at any stage during the movement.

3.3.3.8 Hip external rotation

The subject was seated on the plynth with the left/right leg resting on the plynth with the foot projecting over the end of the plynth. The knee of the measured leg was fully extended and the non-measurement leg was extended downward with the foot resting on the floor.

The Leighton

Flexometer was fastened to the sole of the measurement foot, midway between the calcaneus and the phalanges. From the starting position, the measured foot everted as far as possible where the reading was then taken. The hips had to remain stable and the knee and ankle joints locked throughout the range of motion.

3.3.4

Field tests

3.3.4.1 Multistage shuttle run

The multistage shuttle run test is used to predict the maximal oxygen consumption of an individual. It has been selected as the test of aerobic power for three reasons. Firstly, the test is a sufficiently accurate estimate of aerobic power; secondly, the activity is similar to badminton with respect to the stop, start and change-of-direction movement patterns; and thirdly because it is a time-efficient test where a whole team (such as the national elite junior badminton squad) can be assessed simultaneously (Ellis et al., 2000).

Test protocol Multistage shuttle run (Leger et al., 1988) Equipment and materials that were needed included: a 20m non-slip flat surface, a SHARP QT-CO77 stereo radio cassette recorder with compact disc player, audio cassette, measuring tape to measure the 20m distance correctly, marker beacons, and at least two testing personnel to conduct the test. Two lines were marked out on a rubber gymnasium surface, 20m apart.

The subjects ran back and forth on this 20m straight course, touching the 20m line with one foot at the precise moment that a sound signal was emitted from the audiotape. The subjects were not allowed to run in wide circles, but had to place a foot just over the line and then turn immediately to face and run in the opposite direction. The frequency of the sound signal increased in such a way that running speed was increased by 0.5km/hr each minute, from an initial running speed of 8.5km/hr (Leger et al., 1988). When the subject could no longer maintain the prescribed pace, the score was taken as the last shuttle where his/her foot crossed the line prior to or at the same time as the signal.

This score was

recorded and used to predict the maximal oxygen uptake of the individual. As the subject ran, the tape informed the tester which level and shuttle the subject was on. The subjects received two warnings for not reaching the line at the time of the auditory signal. The test was ended on the third warning

3.3.4.2 SEMO agility test

The SEMO agility test is used to measure the general agility of the body in manoeuvring forward, backward, and sideward.

Test protocol

SEMO agility test (Johnson and Nelson, 1986) Equipment and materials needed included: a smooth area 3.6 x 5.77m, with adequate running space around it, four beacons and a stopwatch. The beacons were placed squarely in each corner of the prescribed area (refer to Appendice D, page 156). After three practice trials, the subject lined up outside the first beacon at A with his back to the rest of the test area. At the signal “Ready, go!” the subject side stepped from A to B (making sure not to use the crossover step), passed outside the corner beacon (B); then back-pedalled from B to D keeping his/her back perpendicular to an imaginery line connecting the corner cones, and passed to the inside corner of the beacon (D). The subject then sprinted forward from D to A and passed the outside the corner beacon (A); then back pedalled from A to C and passed to the inside of the corner beacon (C).

The subject then sprinted forward from C to B and passed the

outside of the corner beacon (B), finally side stepping from B to the finish line at A. Two trials were allowed and the better of the two trials (recorded to the nearest 1/10 sec) was recorded as the score. Incorrect procedures made the trial invalid, and the subject had to then be tested until one correct trial was completed.

3.3.4.3 Muscular endurance tests

The muscular endurance tests are used to determine trunk, abdominal, and upper body endurance of the subjects.

3.3.4.3.1

Sit-ups

Test protocol Sit-ups (2 minutes) – SISA protocol (Nowak, I., 1998). The subject started the sit-up test in a supine position with his/her hands touching the ears, knees bent at 90 degrees, and feet fixed (by an assistant holding them down). The tester’s hand was placed with the palm side up on the floor, so that the palm made contact with the spine in line with the inferior border of the scapulae. The subject proceeded, at the start of the signal, to sit-up and touch his/her knees with his/her elbows, before descending again to touch the tester’s hand.

The subject’s hands had to touch his/her ears for the

duration of the sit-ups. This procedure was continued for the duration of the two full minutes.

The subjects were allowed to rest within the two-minute period and then re-start. If the subject’s hands were taken off the ears, the elbows did not touch the knees, or the back did not touch the tester’s hand, the sit-up was considered invalid. The maximum number of sit-ups completed in the two minutes was recorded.

3.3.4.3.2

Push-ups

Test protocol Push-ups (1 minute) – SISA protocol (Nowak, I., 1998). The male subjects assumed a position with their thumbs shoulder-width apart, facing the floor, with their body weight resting on their hands and toes.

The female subjects assumed a similar position as the male

subjects, only their body weight rested on their hands and knees. The arms had to be fully extended. The subject had to, at the start signal, flex the elbows and decend to and touch the tester’s fist, keeping the back and body straight. The tester’s fist was positioned on the floor below the sternum of the subject. The subject then extended the elbows until they were fully extended. This action was continued for the duration of the test. The push-ups were counted when the subject reached the full elbow extension position.

The subjects were allowed to rest within the one minute period, but only in the full elbow extension position. The male subjects were not allowed to drop to their knees and the female subjects were not allowed to sit back if a rest was required. If the subjects did not adhere to these specifications, the repitition was considered invalid.

The total number of push-ups

performed in one minute was recorded.

3.3.4.4

Speed

To move quickly on a badminton court is a question of acceleration, and braking as quickly as possible (Omosegaard, 1996). This speed test is used to determine the acceleration speed of the subjects.

Test protocol Omosegaard (1996:45 - 46) The longest distance a badminton player would have to run from corner to corner without changing direction is approximately seven meters (Omosegaard, 1996). The ideal distance to test is two to four meters as this is the average distance covered per shot. To test these distances, photocell equipment, a tape measure and tape were needed. A distance of six meters was measured and marked on a flat, smooth surface. Photocell equipment was placed at the start and at two, four and six meter markings.

The player started one metre behind the start line as if he/she was in the playing centre anticipating a return from the opponent, with a badminton racket in his/her playing hand and small pre-tension jump on both legs. After the command “Now!”, the player sprinted to the six meter line. The player then started one metre behind the start line with his/her back to the direction of the movement with a badminton racket in his/her hand and a small pre-tension jump on both legs. On the command “Now!”, the player ran backwards using badminton footwork with the playing hand side turned backwards in the direction of the movement. The best of three trials was recorded for both the forward and backward sprinting tests.

3.3.4.5

Explosive power

A common impression of an explosive player is one who has quick, smooth footwork, with long and/or high jumps as a natural part of the movement (Omosegaard, 1996). Two explosiveness tests were used to determine the explosive power of the legs of the subjects, namely the Sargent vertical jump test and the lunge jump test. These tests respectively measured the instantaneous vertical and horizontal explosive power.

3.3.4.5.1

Sargent vertical jump

Test protocol Sargent vertical jump test (Johnson and Nelson, 1986) Equipment needed for this test included powder and a tape measure mounted to a wall.

The subject stood with his/her playing-hand-side

pelvis against the wall with the mounted tape measure. To record the subject’s standing height, the subject dipped his/her fingertips in the powder and then reached up as far as possible to make a mark with the powder with his/her playing hand. Both feet had to remain flat on the ground when the standing height was being recorded. The subject dipped his/her fingertips of the playing hand into the powder again and then, from a two-footed take-off position, the subject jumped as high as possible, flexing the hip and knee joints and using the arms to gain upward momentum.

A mark was made with the powder at the

highest point touched by the subject. The subject was not allowed to take any form of step or shuffle prior to the jump. The score for the jump was the difference between the standing height and the jumping height. The highest of three separate trials was recorded as the subject’s maximum score.

3.3.4.5.2

Lunge jump

Test protocol Lunge jump test – Omosegaard (1996) This test required a smooth, flat surface and a tape measure and tape for marking. A starting line was marked on the surface. The test started with the measurement of a full static lunge, which was measured with the back knee touching the ground, and the front knee flexed to 90 degrees. The distance was measured from the toe of the back foot to the heel of the front foot. The subject jumped forward with his/her lunge leg (same side as racket playing arm), and backwards to behind the starting line. During the lunge jump, the back leg was not allowed to touch the ground. The subject jumped forward and backwards again, each time trying to get further than the previous jump. The subject kept jumping until he/she could no longer jump back in balance behind the starting line.

The score was the

difference between the length of the standing lunge and the maximum lunge jump length.

3.3.5 Isokinetic dynamometry

3.3.5.1 Introduction

The Cybex Norm Isokinetic Dynamometer (Cybex II, Cybex Isokinetic System, New York) was used in this study to measure the muscular strength of the dominant and non-dominant knee flexors and extensors, as well as the power-endurance of the dominant arm internal and external rotators. The leg strength test was completed in an “up” seated position, with the trunk and thigh of the subject fully supported with secure stabilization straps. The knee/hip adapter and length of limb adapter was adjusted accordingly and the axis of rotation was set. An allowance was made for gravity correction, and the range of motion was set and recorded. The arm power endurance was completed with the subject in a supine position with the arm in a 90 degree abduction position. The torso was secured with stabilizing straps, and the forearm was strapped into the elbow stabilizer pad. The feet could either be positioned on the footrest, or on the chair itself. The subject was positioned for the correct axis of rotation, and the anatomical zero and range of motion was set and recorded.

3.3.5.2 Isokinetic test protocol

Knee flexors and extensors Each subject was tested on the Cybex II Isokinetic Dynamometer to determine absolute and relative peak torque of the hamstring and quadriceps muscle groups, as well as the functional and conventional hamstring:quadriceps ratios as suggested by Agard (1998). Concentric flexor and extensor, and eccentric flexor strength measurements were determined with five repetitions at a velocity of 60 deg.sec-1 Prior to testing, each subject underwent a five-minute cycle on a mechanical bicycle ergometer (Monark 818E, Varberg, Sweden) with a resistance of

0.5kg and at a speed of 70 - 80rpm. This was then

followed by thirty second static stretching of the quadriceps, hamstring and calf muscles. For each stretch the muscle involved was extended and held in the stretch position for thirty seconds The non-dominant leg was tested first. In order to familiarize the subject with the testing equipment, the subject performed five repetitions at a velocity of 180 deg.sec-1. The subject then performed five sub-maximal repititions at 60 deg.sec-1 as practice trials for the test. The practice trial repetitions started with minimal effort and increased with intensity so that the last repetition was at a maximal level. The practice trial warm-up was followed by a one-minute rest.

The subject was then instructed to

complete five consecutive maximal leg extensions and flexions.

The subject then had a three-minute rest, which was followed by five submaximal eccentric flexion practice trials at 60 deg.sec-1. The subject was instructed to perform five consecutive maximal eccentric flexion contractions following the five eccentric practice trials. This was followed by a five-minute rest in which the Cybex machine was set up for the dominant leg. The same procedure occurred with the dominant leg. The subject was instructed to cycle on the Monark bicycle ergometer for five minutes after completing the test, before stretching the quadriceps, hamstring and calf leg muscles as in the warm up stretching.

Shoulder internal and external rotation power-endurance Each subject was tested on the Cybex II Dynamometer to determine the dominant arm internal and external rotation power-endurance. Relative arm power-endurance was measured with ten repetitions at a velocity of 180 deg.sec-1. The subject performed a five-minute warm up on the Concept II rowing ergometer prior to the testing. This was followed by thirty second static stretching of the shoulder internal and external rotator muscles. For each stretch, the muscles involved were stretched and held in the stretched position for thirty seconds. The subject had a five repetition practice trial at a velocity of 180 deg.sec-1, and was then instructed to perform ten consecutive maximal internal and external rotations as fast as possible.

The subjects were instructed to stretch the shoulder internal and external rotator muscles as in the warm up following the isokinetic arm tests.

3.4

STATISTICAL ANALYSIS

Descriptive statistics were used to describe the physiological variables both numerically and graphically by means of the mean and standard deviation.

CHAPTER 4:

4.1

RESULTS AND DISCUSSION

INTRODUCTION

The physical requirements of racquet sports demand efficiency in a number of fitness components. To be able to compete effectively against stronger opponents and execute advanced strokes, a player needs to develop high levels of the basic physical qualities, such as strength, power, muscular endurance, flexibility, speed, coordination and agility. The physical fitness components important to the game of badminton that will be discussed include: body composition, aerobic ability, muscular characteristics, speed, flexibility and agility.

4.2

BODY COMPOSITION

TABLE 1 Physical characteristics of elite junior male badminton players. Subjects

Age

Body Mass

Height

Body Fat

(yrs)

(kg)

(cm)

(%)

59.3

177.9

7.1

73.3

182.8

11.3

67.8

170.5

8.8

67.1

167.5

11.8

76.9

185.7

10.1

69.7

180.6

8.8

86.7

188.6

8.4

86.8

189.9

10.7

Mean

73.4

180.4

9.6

+ 9.7

+ 8.1

+ 1.6

Male

Abbreviations:cm,

centimetre;

kg,

kilogram;

percentage;

SD,

standard deviation;

yrs,

years.

TABLE 2 Physical characteristics of elite junior female badminton players. Subjects

Age

Body Mass

Height

Body Fat

(yrs)

(kg)

(cm)

(%)

53.3

157.9

18.4

155.9

10.9

168

21.1

59.2

160.2

16.1

58.3

160.8

23.7

67.9

165.9

21.7

55.9

160

22.6

Mean

58.1

161.2

19.2

+ 7.9

+ 4.3

+ 4.5

Female

Abbreviations:cm,

centimetre;

kg,

kilogram;

percentage;

SD,

standard deviation;

yrs,

years.

4.2.1 Height

The male subjects in this study had a mean height of 180.4 + 8.1cm (n=8) (Table 1). This value is similar to that of national class badminton, state and top club level tennis players and national elite Swedish tennis players who have recorded mean heights of 181.0 + 5.7cm, 175.4 + 5.4cm, 181.0 + 0.02cm, 182 + 7cm and 184 + 6cm respectively (Andersson et al., 1988; Christmass et al., 1995; Reilly and Palmer, 1995; Faccini and DalMonte, 1996 and Majumdar et al., 1997). Height values from studies performed by Rannou et al. (2001) on national and international handball players show mean height values of 177.0 + 1.4cm and 190.0 + 1.2cm respectively. These height values are higher than values found in junior tennis players, top squash players, junior national squash players, and professional soccer players who have recorded mean heights of 163.4 + 9.4cm to 174.5 + 0.7cm (Elliot et al., 1989 and 1990 and Todd and Mahoney, 1995), 166cm to 180cm (Chin et al., 1995), 173.0 + 6.4cm (Mahoney and Sharp, 1995) and 172.0 + 6.2cm to 177.2 + 4.0cm (Chin et al., 1992 and 1994) respectively. The mean height of the female subjects in this study of 161.2 + 4.3cm (n=7) (Table 2), corresponds with values found in junior female badminton and tennis players who have recorded mean values that range from 160cm to 165cm (Dias and Ghosh, 1995), and from 162.8 + 7.5cm to 165.1 + 5.2cm (Elliot et al., 1989 and 1990) respectively. These values are lower than values obtained in research by Powers and Walker (1982), and

Hughes

(1995)

who

recorded

mean

height

values

168.70 + 2.35cm for female high school players, and 166.5 + 6.4cm for senior national badminton players respectively.

Body height does not seem to be a determinant of success in badminton (Reilly et al., 1990), as most players are taller than the top of the badminton net. Players with above average heights however, may have an advantage when smashing, as the angle of the smash would be a lot steeper due to the shuttle being hit at a higher point. This would make it more difficult for the opponent to return. Above average heights would also enable the player to intercept the shuttle sooner and thus force a more attacking form of play. The average heights of the male and female badminton players in this study are higher than the standard badminton net height, which is 1.52 to 1.55 metres from the floor. Both the males and females would therefore be at an advantage, with the males having a greater advantage as they are on average approximately 20cm taller than the females.

4.2.2 Mass

The male subjects in this study had a mean mass of 73.4 + 9.7kg (n=8) (Table 1). This value corresponds with values obtained from elite Danish badminton players and handball players whose values range from 73.3kg to 76.9kg (Omosegaard, 1996), and from 74 + 2kg to 79.4 + 0.8kg (Rannou et al., 2001) respectively.

It is however, higher than values

obtained from studies on national male badminton players, leading junior tennis players, top squash, and professional soccer players who have recored values of 69.8 + 4.8kg and 64.8 + 6.9kg (Faccini and DalMonte, 1996 and Majumdar et al., 1997), 49.3 + 8.8kg to 59.5 + 8.2kg (Elliot et al., 1989 and 1990), and 67.7 + 6.9kg and 67.7 + 5.0kg (Chin et al., 1992 and 1995).

The female subjects in this study had a mean mass of 58.1 + 7.9kg (n=7) (Table 2). This mean value tends to correspond closely with that of elite female Danish badminton players, female high school tennis players and leading junior tennis players, whose values ranged from 57.0 to 66.7kg (Omosegaard, 1996), 57.99 + 2.59kg (Powers and Walker, 1982) and 56.2 + 8.1kg (Elliot et al., 1989).

These values however, are slightly

higher than values obtained for 14 to 15 year old leading female tennis players of 52.5 + 7.2kg and 54.2 + 6.8kg by Elliot et al. (1989 and 1990). In Reilly et al. (1990), it was concluded that lean body mass rather than total body weight was the critical factor relative to performance ability. According to Jaski and Bale (1987), a moderate increase in lean body mass will result in greater speed, strength and power without a loss of flexibility and agility. This corresponds with Chin et al. (1994) who stated that soccer players with a high lean muscle mass would be able to generate higher forces for jumping, kicking, and tackling. Body mass tends to play an important role in sports requiring the repeated lifting of the body against gravity in movement during exercise (Reilly et al., 1990), such as in badminton, as energy is required in moving the excess mass around the court (Elliot et al., 1989 and Chin et al., 1995). On average, both the male and female players in this study have body mass values that will be neither advantageous or disadvantageous to their game.

Individually however, there are a couple of male and

female players who would be at a slight disadvantage as their mass is higher than average, and a male and female player who would have a slight advantage as their mass is lower than average.

4.2.3 Percentage body fat

The male subjects in this study had a mean body fat percentage of 9.6 + 1.6% (n=8) (Table 1). This value corresponds with those of national badminton players, first league and junior national squash players and male college tennis players who had mean body fat percentages of 9.8 + 3.5% (Faccini and DalMonte, 1996), 10.1 + 2.7% and 10.9 + 1.8% (Van Rensburg et al., 1982 and Mahoney and Sharp, 1995), and 10.4 + 3.2% (Groppel and Roetert, 1992), respectively. A mean body fat percentage of 12.1 + 3.4% was found for national male badminton players by Majumdar et al. (1997), which corresponds more closely with values found in squash and handball players. Body fat percentages found in squash players ranged from 7.4 – 12% (Pyke et al., 1974 and Chin et al., 1995), and in handball players ranged from 8.1 – 13.2% (Pipes, 1979 and Rannou et al., 2001). These values are higher than values found in top squash and soccer players by Chin et al. (1992, 1994 and 1995) who found mean body fat percentages of 7.4 + 3.4%, 5 + 1.2% and 7.3 + 3%, respectively. The female subjects in this study had a mean body fat percentage of 19.2 + 4.5% (n=7) (Table 2).

This value is lower than body fat

percentages obtained from studies of female high school tennis players and senior national badminton players who have recorded means of 23.3 + 0.66% (Powers and Walker, 1982) and 23.6 + 3.3% (Hughes, 1995) respectively. It is in the below average percentage value for women where the average value is 23% Heyward (1998). The body fat values for the females is higher than that of the males, which corresponds with Groppel and Roetert (1992) who noted that tennis girls have higher body fat values than tennis boys.

Although body size is not an essential determinant of success in badminton, the body fat percentage of an individual does play a role in performance. In research performed by Elliot et al. (1990) on junior male and female tennis players, body composition was found to be an important indicator of tennis performance for 11 - 15 year old male and female players. This corresponds with Mahoney and Sharp (1995), who state that body fat could be a factor limiting performance. Excess body weight as fat would be disadvantageous in moving quickly around the court, as well as jumping to strike the shuttle. Top competitive players tend to have a low body fat percentage, as the negative impact of excess body fat would increase the energy expended in moving around the court (Elliot et al., 1989 and Chin et al., 1995). Lower levels of body fat will enhance the game of badminton as it permits a more effective gradient for the rapid transfer of heat produced during high intensity exercise, and would be advantageous with regards to moving quickly across the court and in leaping to strike the shuttle. The body fat percentage values of elite young male athletes seem to be well below the average of fifteen percent.

The average body fat

percentages of badminton players should range between 10 and 15 percent for males, and between 15 and 20 percent for females.

Any

athlete with a higher fat percentage is likely to be at a disadvantage when playing against a leaner badminton player. The male players on average, as well as individually, have body fat percentages within the range required and would therefore not be at a disadvantage. The average body fat percentage value for the females is within the range, but could be lower for a more optimal advantage. Individually, a couple of the females would be at a greater advantage compared to the other players, as the rest of the players values are higher than average.

4.2.4 Somatotype

FIGURE 1 Somatotype (mean + SD) of males and females.

Abbreviations:n,

sample number;

SD,

standard deviation.

Endomorphy

n=7 n=8

6.0 4.0 2.0 0.0

Males

Females

Mean

Mesomorphy

n=7

n=8

6.0 4.0 2.0 0.0

Males

Females

Mean

Ectomorphy

n=8

6.0

n=7

4.0 2.0 0.0

Males

Females Mean

The male subjects in this study recorded a 3.0 : 4.1 : 3.1 + 1.0 : 1.1 : 1.0 somatotype (n=8) (Figure 1). The endomorphic component is higher than that of junior tennis players as well as first league squash players. The mesomorphic component is on par with the tennis and squash players, and the ectomorphic component is lower than the tennis players, but higher than the squash players. The junior tennis players studied by Elliot et al. (1989) had a 2.1 : 3.8 : 4.2 + 1.0 : 1:1 . 1.0 somatotype for 14 to 15 year old players, and a 2.2 : 4.1 : 3.9 + 0.9 : 0.6 : 1.1 somatotype for the 16 to 17 year old players. Elliot et al. (1990) found a 1.9 : 3.9 : 4.5 + 0.6 : 1.1 : 1.0 somatotype for the 15 year old players. The squash players studied by Van Rensburg et al. (1982) had a 1.9 : 4.2 : 2.7 somatotype. The males of this study had a similar body shape to the 16 to 17 year old junior tennis players. The female subjects in this study recorded a 4.0 : 4.3 : 2.0 + 1.0 : 1.1 : 0.7 somatotype (n=7) (Figure 1). Compared to junior female tennis players, the endomorphic and mesomorphic components of the players in this study are similar, but the ectomorphic component is lower. The 14 to 15 year old junior female tennis players studied by Elliot et al. (1989) had a 4.0 : 3.3 : 3.4 + 1.5 : 1.1 : 1.3 somatotype, whereas the 16 to 17 year old players had a 4.2 : 3.4 : 3.1 somatotype. In the 1990 study, the 15 year olds had a 3.9 : 3.2 : 3.4 + 1.0 : 1.0 : 1.2 somatotype. The somatotype measurement is an indication of the general build or configuration of an individual. The three components of the somatotype include the relative fatness (endomorphy), the relative musculoskeletal robustness (mesomorphy) and the relative linearity (ectomorphy) of the individual, and the highest value gives an indication of the general shape of the individual.

Both the male and female badminton players in this study are highest in their mesomorphic components. The endo and ectomorphic values were found to be similar, but slightly lower than the mesomorphic value. To gain an advantage in badminton the players should preferably have a tall, lean and muscular build. They would need to be high in their meso and ectomorphic components, and low in their endomorphic component. Both the male and female players could be at a slight disadvantage due to the high endomorphic value.

4.3

AEROBIC POWER

4.3.1 Maximal oxygen consumption

FIGURE 2 Maximal oxygen consumption (mean + SD) of males and females.

Abbreviations:n,

sample number;

SD,

standard deviation.

n=8

n=7

VO max (mlO /kg/min)

50 40 30 20 10 0

Males

Females

Mean

The mean maximal oxygen consumption of the males in this study was 50.7 + 3.0mlO2.kg-1.min-1 (n=8) (Figure 2). Compared to values obtained from badminton players in studies performed by Mikkelsen (1979), Chin et al. (1995), Faccini and DalMonte (1996), Omosegaard (1996) and Majumdar et al. (1997), this value is fairly low. The values obtained in these studies ranged from 55.7 – 73.0 mlO2.kg-1.min-1. Values for male squash players range from 51.9 – 65.7mlO2.kg-1.min-1 (Van Rensburg et al., 1982; Steininger and Wodick, 1987; Reilly et al., 1990 and Todd and Mahoney, 1995). The mean value of the males in this study closely corresponds with the mean value for the national junior male squash players in a study performed by Mahoney and Sharp (1995) of 52.6mlO2.kg-1.min-1. The average range for elite handball players is from 50 - 65mlO2.kg-1.min-1 (Alexander and Boreski, 1989; Loftin et al., 1996 and Rannou et al., 2001). The maximal oxygen consumption of tennis players is considerably lower than that of badminton, squash and handball players. The values obtained from studies performed by Groppel and Roetert (1992); Christmass et al. (1995); Omosegaard (1996); Buckeridge et al. (2000) and Smekal et al. (2001) showed mean values that ranged from 44 – 65mlO2.kg-1.min-1. The mean maximal oxygen consumption of the females in this study was 42.0 + 2.8mlO2.kg-1.min-1 (n=8) (Figure 2). Compared to values obtained from badminton players in studies performed by Chin et al. (1995); Hughes (1995); Omosegaard (1996) and Larsson (1999), this value is also fairly low.

The values obtained in these studies ranged from

50 – 63mlO2.kg-1.min-1. -1

53 – 56mlO2.kg .min

-1

Values for female squash players range from (Steininger and Wodick, 1987 and Reilly et al.,

1990). The values obtained from studies on tennis players performed by Powers and Walker (1982), Reilly and Palmer (1995), Ferrauti et al. (1998) and Buckeridge et al. (2000) show mean values that range from 39.0 – 51.5mlO2.kg-1.min-1.

The values of the females in this study tend to have similar values to female tennis players, which is quite low. Female athletes tend to have smaller maximal oxygen consumption values compared to males (Noakes, 1986; Omosegaard, 1996; Plowman and Smith, 1997 and Withers et al., 2000), which corresponds with McMurray et al. (2002), who observed that eight to sixteen year old girls have a lower maximal oxygen consumption value than similar aged boys in both absolute and relative terms. Relative values for males tend to be 20 - 30% higher than females (Plowman and Smith, 1997).

The lower values are due to body

composition differences (larger muscle mass in boys and higher fat content in girls), a smaller stroke volume and lower hemoglobin concentrations in females. The greatest maximal oxygen consumption values are found in endurance sports such as long distance running and skiing, and are due to a combination of genetic endowment and training (Withers et al., 2000). Athletes whose performance depends on the ability of the cardiovascular system to sustain dynamic exercise consistently (such as badminton), tend to have higher maximal oxygen consumption values than athletes whose performance is based mostly on motor skills. This explains why the normative data on elite badminton players is relatively high. Badminton at an elite level requires a combination of aerobic and anaerobic systems, depending on the nature of the rally and game. Due to the fact that 60 - 70% of energy in a game of badminton is derived from the aerobic system (Chin et al., 1995), the aerobic capacity of a player is an important fitness parameter that needs to be taken into consideration.

Maximal oxygen consumption values for badminton players on average tend to be higher than tennis, squash, handball and raquetball players (Omosegaard, 1996), which confirms that badminton is an intermittent sport demanding excellent aerobic qualities that would enable the player to endure both the intensity and length of matches (Faccini and DalMonte, 1996), as well as have a faster recovery rate. Both the male and female maximal oxygen consumption values are low compared to values found in other badminton players. The players are therefore at a disadvantage as they wouldn’t be able to keep up to the more intensive force of play by an opponent with a higher maximal consumption value, they would not be able to endure the length and intensity of the matches as comfortably as they could, and their recovery rate would be slower.

4.4

MUSCULAR CHARACTERISTICS

FIGURE 3 The muscular characteristics (mean + SD) of males (n=8).

Abbreviations:BW,

body weight;

Nm,

Newton metre;

percentage;

SD,

standard deviation;

D CE,

dominant leg concentric extension;

D CF,

dominant leg concentric flexion;

ND CE,

non-dominant leg concentric extension;

ND CF,

non-dominant leg concentric flexion.

Absolute peak torque 300 250

200 150 100 50 0

D CF

ND CF Mean

D CE

ND CE

Relative peak torque 350 Nm as % of BW

300 250 200 150 100 50 0

D CF

ND CF Mean

D CE

ND CE

FIGURE 4 The muscular characteristics (mean + SD) of females (n=7).

Abbreviations:BW,

body weight;

Nm,

Newton metre;

percentage;

SD,

standard deviation;

D CE,

dominant leg concentric extension;

D CF,

dominant leg concentric flexion;

ND CE,

non-dominant leg concentric extension;

ND CF,

non-dominant leg concentric flexion.

Absolute peak torque 200 180 160 140 Nm

120 100 80 60 40 20 0

D CF

ND CF Mean

D CE

ND CE

Relative peak torque 300

Nm as % of BW

250 200 150 100 50 0

D CF

ND CF Mean

D CE

ND CE

4.4.1 Concentric strength

Badminton is a sport that is strength related, rather than strength limited in that the performance of a player is influenced by strength, not limited by it (Wrigley and Strauss, 2000). Badminton at the highest level puts a great demand on leg strength and according to Omosegaard (1996) it is footwork at the playing centre and in connection with hitting the shuttle that requires muscle strength.

4.4.1.1

(i)

Absolute peak torque

Hamstrings

The male subjects in this study had a mean absolute peak torque of the concentric flexors of 130 + 20Nm in the dominant leg, and a mean peak torque of 132 + 17Nm in the non-dominant leg (n=8) (Figure 3). The females had a mean peak torque of 93 + 21Nm in the dominant leg, and a mean peak torque of 87 + 18Nm in the non-dominant leg (n=7) (Figure 4). No significant difference in strength was found between the dominant and non-dominant legs in both the males and females in this study.

(ii)

Quadriceps

The male subjects in this study had a mean absolute peak torque of the concentric extensors of 209 + 47Nm in the dominant leg, and a mean peak torque of 213 + 46Nm in the non-dominant leg (n=8) (Figure 3). The females had a mean peak torque of 154 + 35Nm in the dominant leg, and a mean peak torque of 139 + 37Nm in the non-dominant leg (n=7) (Figure 4). No significant difference in absolute strength was found between the dominant and non-dominant legs in the males in this study. The strength of the dominant leg of the females however, was slightly higher than that of the non-dominant leg, but not significantly so.

4.4.1.2

(i)

Relative peak torque

Hamstrings

The mean relative peak torque of the concentric flexors of the male subjects in this study was 178.0 + 13.9% in the dominant leg, and 182.6 + 25.3% in the non-dominant leg (n=8) (Figure 3). The females had a mean peak torque of 154.6 + 13.0% in the dominant leg, and a mean peak torque of 149.0 + 18.3% in the non-dominant leg (n=7) (Figure 4).

No significant difference in relative strength was found between the dominant and non-dominant legs in both the males and females in this study.

(ii)

Quadriceps

The male subjects in this study had a mean relative peak torque of the concentric extensors of 286.3 + 46.2% in the dominant leg, and a mean peak torque of 277.7 + 48.2% in the non-dominant leg (n=8) (Figure 3). The females had a mean peak torque of 259.6 + 21.6% in the dominant leg, and a mean peak torque of 238.4 + 33.8% in the non-dominant leg (n=7) (Figure 4). The relative strength values of the dominant leg in both the males and females were found to be higher than the non-dominant leg.

(iii)

Hamstring:quadricep ratio

TABLE 3 The hamstring:quadricep ratio of elite junior badminton players. Males (n=8)

Females (n=7)

Mean

D leg con flex:con ext

60.1

11.4

57.5

ND leg con flex:con ext

58.5

6.9

8.4

Abbreviations:con,

concentric;

dominant;

ext,

extension;

flex,

flexion;

ND,

non-dominant;

SD,

standard deviation.

The male mean peak torque concentric flexion:concentric extension ratio was 60.1 + 11.4% for the dominant leg, and 58.5 + 6.9% for the nondominant leg (n=8) (Table 3). The female mean peak torque concentric flexion:concentric extension ratio was 57.5 + 5.0%, for the dominant leg and 59.0 + 8.4% for the nondominant leg (n=7) (Table 3).

4.4.1.3

Discussion

The relative strength values of the dominant leg in both males and females in this study were found to be higher than the non-dominant leg. This coincides with studies performed by Mikkelsen (1979) on top Danish and Dutch badminton players who showed that muscle hypertrophy of badminton players tended to be unilaterally biased, with the right calves and thighs of the right handed players being significantly bigger. This, according to Reilly et al. (1990), is due to the use of the preferred leg in generating force against the ground in the step prior to hitting the shuttle. Other reasons for the right leg being significantly bigger than the left (for right handed players) is that 80 - 90% of all “braking” in the corners are done on the right leg and the right leg is almost always used in the lunge jump, in all net returns, and in situations under pressure anywhere on the court (Omosegaard, 1996).

The demands of leg strength are greater on the right leg than on the left (for a right-handed player). The opposite would be true for left handed players (Omosegaard, 1996). In studies performed on elite junior tennis players however, it was found that there were no significant differences in strength between the extremities in the quadriceps or hamstrings muscles, showing that there was no lower extremity dominance.

The

same was found for normal populations and soccer players (Ellenbecker and Roetert, 1995). In an unpublished study performed on elite Danish badminton players in connection with the “Olympic Games 1992 - project” by Omosegaard et al. (1995), it was found that badminton players have strong knee, hip and ankle extensors, but that the strength in the hamstrings was not proportionately developed.

This resulted in the hamstring:quadriceps

ratio of the players being quite low, which in turn could result in an increased risk of knee injuries. The normal hamstrings:quadriceps ratio should be 67% (Perrin, 1993). Ratios from the Hong Kong, Singapore and Australian junior squash teams range from 59.4 – 62.0%, whereas the Hong Kong badminton team had a lower ratio of 55.5% (Chin et al., 1995).

The strength ratios of elite junior tennis players in a study

performed by Ellenbecker and Roetert (1995) ranged between 59 and 69%, indicating a quadricep dominance in the players. The players in this study all had low ratios, indicating that the hamstrings were not well proportionally developed. This could lead to an increased risk of knee injuries, which is already a common problem among elite senior badminton players. Individual analysis however, indicated that a couple of players had normal hamstring:quadricep ratios, which is an advantage to those specific players.

4.4.2 Eccentric strength

Eccentric strength is important in badminton as it is involved in braking when landing and in pushing-off towards the playing centre. A greater eccentric strength of the legs could improve a badminton player’s speed on the court due to the fact that less time in braking is indicative of a greater maximum eccentric strength (Omosegaard, 1996).

TABLE 4 Eccentric quadricep strength of elite junior badminton players. Males (n=8)

Females (n=7)

Mean

Dominant leg

157

115

Non-dominant leg

160

117

Dominant leg

218

195

Non-dominant leg

222.3

67.5

197.6

27.6

Absolute peak torque (Nm)

Relative peak torque (Nm as % BW)

Abbreviations:BW,

body weight;

Nm,

Newton metre;

percentage;

SD,

standard deviation.

4.4.2.1

(i)

Absolute peak torque

Quadriceps

The male subjects in this study had a mean absolute peak torque of the eccentric flexors of 157 + 25Nm in the dominant leg, and a mean peak torque of 160 + 42Nm in the non-dominant leg (n=8) (Table 4). The females had a mean peak torque of 115 + 28Nm in the dominant leg, a mean peak torque of 117 + 27Nm in the non-dominant leg (n=7) (Table 4). No significant difference was found in the eccentric strength between the dominant and non-dominant legs in both the males and females in this study.

4.4.2.2

(i)

Relative peak torque

Quadriceps

The male subjects in this study had a mean relative peak torque of the eccentric flexors of 218 + 39% in the dominant leg, and a mean peak torque of 222.3 + 67.5% in the non-dominant leg (n=8) (Table 4). The females had a mean peak torque of 195 + 24% in the dominant leg, and a mean peak torque of 197.6 + 27.6% in the non-dominant leg (n=7) (Table 4).

4.4.2.3

Discussion

No significant difference was found in the relative eccentric strength between the dominant and non-dominant legs in both the males and females in this study, and it was found that the relative eccentric strength of the quadriceps of both the dominant and non-dominant leg of the males and females in this study was lower than the concentric strength. Due to the fact that eccentric strength is important for braking and pushing off in badminton, the players would be at a disadvantage as more time would be spent in braking and pushing off. This would have a negative affect on players who use attacking tactics in their game.

4.4.3` Power

According to Roetert et al. (1996), a vital aspect of sports such as tennis and badminton is the ability of the player to exert muscular force at high speed.

Many sports require a generation of high forces and power

outputs (Reilly et al., 1990), and badminton at the highest level places a great demand on explosive power (Omosegaard, 1996). It was found in an on-court video analysis by Omosegaard (1996) that the acceleration during braking and push offs is due to muscle power.

4.4.3.1 Leg power

Leg power is an important component in badminton in that it results in the player being able to move quickly and explosively to the shuttle in various directions and to jump high to play overhead strokes. Greater leg power results in a greater acceleration and faster speed when lifting off the floor when moving, or jumping to the shuttle.

According to Omosegaard

(1996), an explosive player will typically be able to jump high, change direction quickly and will generally appear to be swift and mobile on the badminton court. Leg power is therefore a combination of co-ordination and muscular properties. The vertical and horizontal leg power of the subjects in this study are presented in Figure 5. The vertical jump graph represents the vertical power, and the lunge jump graph the horizontal power.

FIGURE 5 The leg power (mean + SD) of males and females.

Abbreviations:cm,

centimetre;

sample number;

SD,

standard deviation.

Vertical jump n=8

n=7

50 cm

40 30 20 10 0

Males

Females

Mean

Lunge jump

n=7

n=8

60 40 20 0

Males

Females

Mean

The males in this study had a mean vertical jumping height of 53 + 4cm (n=8) (Figure 5).

Male Australian tennis players in Buckeridge

et al. (2000) have mean vertical jumping heights of 53.2 + 4.8cm and 54 + 3cm which corresponds closely with the results obtained by the males in this study. This value however, is lower than values obtained from local league, national league and elite level badminton players by Omosegaard (1996), whose values ranged from 55 – 75cm, but is higher than values obtained from junior tennis players between the age of 14 and 17 years, whose values ranged from 32 – 39cm (Elliot et al., 1989). These values correspond with the 15 year old quarter- and semi-final lawn tennis players in Elliot et al. (1990), who had mean vertical jumping heights of 33 and 34 cm respectively. The mean horizontal jumping distance of the males was 40 + 20cm (n=8) (Figure 5). According to Omosegaard (1996), 60 – 70cm is the minimum range for the lunge jump for male badminton players. The females in this study had a mean vertical jumping height of 35 + 6cm (n=7) (Figure 5). Female Australian tennis players in Buckeridge et al. (2000) have mean vertical jumping heights of 40 + 3cm and 40.3 + 5.2cm, which is slightly higher than the results obtained by the females in this study. The values of the females in this study, however, are lower than values obtained from local league, national league and elite level badminton players by Omosegaard (1996), whose values ranged from 45 – 62cm.

The values tend to correspond more closely with those

obtained from junior tennis players between the age of 14 and 17 years, whose values ranged from 32 – 33cm (Elliot et al., 1989).

This

corresponds with the 15 year old quarter- and semi-final lawn tennis players in Elliot et al. (1990), who had mean vertical jumping heights of 30 and 34cm respectively.

The mean horizontal jumping distance of the females was 42 + 23cm (n=7) (Figure 5). According to Omosegaard (1996), 35 – 45cm is the minimum range for the lunge jump for female badminton players. The vertical power values of the males and females were low compared to that of other badminton players. This is disadvantageous to the players as vertical power is important for jumping high to intercept the shuttle, and in the smash stroke for some players.

Jumping high to intercept the

shuttle will result in a faster and more attacking game as the player is able to intercept the shuttle before it has time to descend. Some players who have mastered the technique of jumping to hit the smash are at an advantage as they create a steeper angle for the shuttle and they also intercept it sooner, making it more difficult for the opponent to return. The females would not be at a great disadvantage with regards to their horizontal power, as their value falls within the normal range for female badminton players.

The male players however would be at a

disadvantage as horizontal power is important in taking lunge jumps to net shots. A greater horizontal power will result in the player being able to reach the shuttle more quickly, and thus force a faster pace of play. This power also helps in getting to un-anticipated shots, where a quick, explosive movement to a relatively far distance has to be made.

4.4.3.2 Arm power-endurance

Speed strength of the rotator muscles of the shoulder is the most important characteristic needed for striking the shuttle (Omosegaard, 1996).

Power is an important component for the arm muscles of the badminton player, and due to the repetitive movements of the arm at high speeds in striking the shuttle, dynamic endurance is also needed. The dominant arm power of the subjects in this study are presented in Figure 6 and Figure 7.

FIGURE 6 The absolute and relative arm power characteristics (mean + SD) of males (n=8).

Abbreviations:BW,

body weight;

con,

concentric;

ext.,

external;

int.,

internal;

percentage;

rot.,

rotation;

SD,

standard deviation.

Absolute arm power

90 80

Watts

70 60 50 40 30 20 10 0

con ext. rot.

con int. rot. Mean

Relative arm power

Watts as % of BW

120.0 100.0 80.0 60.0 40.0 20.0 0.0

con ext. rot.

con int. rot. Mean

FIGURE 7 The absolute and relative arm power characteristics (mean + SD) of females (n=7).

Abbreviations:BW,

body weight;

con,

concentric;

ext.,

external;

int.,

internal;

percentage;

rot.,

rotation;

SD,

standard deviation.

Absolute arm power

45 40 35 Watts

30 25 20 15 10 5 0

con ext. rot.

con int. rot. Mean

Relative arm power

70 Watts as % of BW

60 50 40 30 20 10 0

con ext. rot.

con int. rot. Mean

4.4.3.2.1

(i)

Absolute arm power

External rotators

The mean absolute power of the dominant arm concentric external rotators of the males in this study is 44.1 + 15.3 Watts (n=8) (Figure 6), and the mean absolute power of the dominant arm concentric external rotators of the females in this study is 27.5 + 8.0 Watts (n=7) (Figure 7).

(ii)

Internal rotators

The mean absolute power of the dominant arm concentric internal rotators of the males in this study is 63 + 18 Watts (n=8) (Figure 6), and the mean absolute power of the dominant arm concentric internal rotators of the females in this study is 33 + 12 Watts (n=7) (Figure 7).

4.4.3.2.2

(i)

Relative arm power

External rotators

The mean relative power of the dominant arm concentric external rotators of the males in this study is 60.0 + 17.8 Watts as % of BW (n=8) (Figure 6), and the mean relative power of the dominant arm concentric external rotators of the females in this study is 46.8 + 11.5 Watts as % of BW (n=7) (Figure 7).

(ii)

Internal rotators

The mean relative power of the dominant arm concentric internal rotators of the males in this study is 85.1 + 18.7 Watts as % of BW (n=8) (Figure 6), and the mean relative power of the dominant arm concentric internal rotators of the females in this study is 55.3 + 14.5 Watts as % of BW (n=7) (Figure 7).

(iii)

External:internal ratio

The mean concentric external:concentric internal rotation ratio for the dominant arm of the males in this study was 74.8 + 14.1 Watts as % of BW (n=8) (Figure 6), and for the females was 83.1 + 12.9 Watts as % of BW (n=7) (Figure 7).

100

The external:internal rotation ratio reflects the percentage of the external rotation strength relative to the internal rotation strength (Nowak, 1998), and a value between 60 and 84 Watts as % of BW is within the normal limits.

Both the males and females in this study have a healthy

external:internal rotation ratio in their dominant shoulder.

4.4.3.2.3

Discussion

The absolute and relative internal rotation power of the dominant arm was found to be higher than the external rotation power for both the males and females in this study.

This is due to the fact that overhead forehand

strokes are performed much more than the overhead backhand strokes. Most of the power for explosive overhand strokes comes from the internal rotation of the shoulder and it is in hitting overhead forehand clears and smashes that internal rotation power is mostly required. It has been found that an increased strength in internal rotation occurs in sports where plyometric type movements are used during the acceleration phase, such as in badminton (Chandler et al., 1992).

Players would be at a

disadvantage if their internal rotation power was low as it would mean that they would not be able to clear or smash the shuttle as far and hard as someone with a greater power. This would give the stronger player an attacking advantage. The external rotation of the shoulder is used in the backswing of the stroke for overhead forehand strokes and does not require explosive power.

External rotation power however is important for hitting the

backhand clear, as this movement requires an explosive external rotation of the shoulder.

101

This means that players with a higher external rotation power would possibly be able to have a more powerful backhand clear, which would be advantageous to their game as they would be able to clear the shuttle to the back of the court, giving them more time to recover for the next stroke. Isokinetic data on the shoulder can be used to formulate unilateral ratios and can be used to determine muscle imbalances surrounding a joint. The posterior rotator cuff plays an important role in decelerating and stabilising the humerus during the follow-through for stroke production, and the external rotation strength is important for glenohumeral joint stability. In studies by Chandler et al. (1992) on male and female athletes, the external rotation:internal rotation ratio was found to be 2:3 at both 60 and 180 deg.sec-1. The external:internal shoulder rotation ratio of the both male and female players in this study are high, meaning that the external rotators, even though weaker than the internal rotators, are relatively strong and almost the same strength as the internal rotators.

The

external:internal rotation ratio for the dominant shoulder of both the males and females in this study is within normal limits, and would give the players an advantage.

4.4.3.2.4

Endurance ratio

The endurance ratios of the subjects in this study are presented in Figure 8.

102

FIGURE 8 Arm endurance ratios (mean + SD) of males and females.

Abbreviations:%,

percentage;

SD,

standard deviation.

103

Concentric external rotators n=8

n=7

140 120 100 %

80 60 40 20 0

Males

Female Mean

Concentric internal rotators n=8

n=7

140.0 120.0 100.0 %

80.0 60.0 40.0 20.0 0.0

Males

Female Mean

104

The males in this study had a mean endurance ratio of 105.2 + 24.8% for the concentric external rotators, and an endurance ratio 107.0 + 25.5% for the concentric internal rotators (n=8) (Figure 8). The females had a mean concentric external rotator endurance ratio of 103.7

23.9%,

and

concentric

internal

endurance

ratio

112.5 + 15.3% (n=7) (Figure 8). The endurance ratios of the players in this study were found to be higher than ratios found in male and female college tennis players. Endurance ratios for these players were 88.8 + 22.8% for internal rotation, and 67.3 + 12.9% for external rotation in the dominant arm, at testing speeds of 60 and 300 deg.sec-1.

The non-dominant arm values were similar

Chandler et al. (1992). Badminton involves repetitive movements at high speeds and the endurance ratio of the arm is therefore an important component. Players with a high endurance ratio would be able to play more strokes without getting fatigued in the arms, and last longer during a match against an opponent with a lower arm endurance ratio. A high endurance ratio is also important for attacking players who smash and/or clear a lot during the game as it would allow them to play their repetitive smashes or clears for a longer time before fatigue would set in.

4.4.4 Muscular endurance

The muscular endurance characteristics of the subjects in this study are presented in Figure 9.

The push-ups graph represents upper body

muscular endurance and the sit-ups graph represents abdominal endurance.

105

FIGURE 9 The muscular endurance (mean + SD) of males and females.

Abbreviations:n,

sample number;

SD,

standard deviation.

106

Push-ups

n=7

Number of push-ups

50 n=8

40 30 20 10 0

Males

Females

Mean

Sit-ups

Number of sit-ups

n=7 n=8

80 60 40 20 0

Males

Females

Mean

107

The males in this study had a mean push-up value of 28 + 6 and a mean sit-up value of 56 + 9 (n=8) (Figure 9). The females had a mean push-up value of 40 + 4 and a mean sit-up value of 57 + 17 (n=7) (Figure 9). Compared to normative data obtained by Kibler (1988) on junior tennis players, the males are below average in push-ups and above average in sit-ups, and the females are above average for both push-ups and sit-ups. The push-up values in Kibler (1988) range from 36 – 42 for males and 33 – 38 for females, and the sit-up values range from 44 – 52 for males and 38 – 46 for females. The push-up and sit-up value of the males is also lower than that of squash players in Durandt (1998), who have mean values of 45 and 80 repetitions for push-ups and sit-ups respectively. The female push-up value is higher than and the sit-up value lower than the female squash players who have values of 35 and 80 repetitions for pushups and sit-ups respectively. Dynamic upper body endurance is important for badminton players due to the repetitive nature of striking the shuttle. According to Groppel and Roetert (1992), the upper body can be strong enough, and have the dynamic endurance required simply from the nature of the sport. The male players could be at a disadvantage with regards to their upper body endurance as their values are low. This would have a negative affect on their performance, especially if they are players who use attacking tactics and smash and clear a lot. The female players would have an advantage in their game as their values are above average.

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Well-developed strength and endurance of the trunk muscles also plays an important role in badminton, as trunk movements are large, repetitive and varied. They are important muscles due to the fact that they are virtually involved in every movement and stroke that happens on the badminton court (Omosegaard, 1996).

They perform an important

stabilising and balancing function for all braking and push-offs, and they are directly involved with stroke production. According to Roetert et al. (1996), without sufficient trunk development in terms of strength and endurance, strokes will lack power and control. Both the male and female players have above average abdominal endurance and would be able to endure long, exhausting matches within this context.

4.5

SPEED

Speed is needed in badminton for moving to and from the shuttle, and the ability to cover short distances quickly would be a great advantage for the badminton player (Todd and Mahoney, 1995). Due to the nature of the game and the size of the court, it is important for the badminton player to reach his/her maximum speed as fast as possible. The forward and backward speed of the subjects in this study are presented in Figure 10 and Figure 11.

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FIGURE 10 Forward speed (mean + SD) at 2,4 and 6m of males (n=8) and females (n=7).

Abbreviations:m,

metre;

SD,

standard deviation.

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Males

1.2

Seconds

1 0.8 0.6 0.4 0.2 0

Mean

Females

Seconds

1.5 1 0.5 0

Mean

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FIGURE 11 Backward speed (mean + SD) at 2,4 and 6m of males (n=8) and females (n=7).

Abbreviations:m,

metre;

SD,

standard deviation.

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Seconds

Males

1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0

Mean

Females

Seconds

2 1.5 1 0.5 0

Mean

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The mean forward speed of the males at 2, 4 and 6 metres was 0.44 + 0.03, 0.80 + 0.04 and 1.14 + 0.05 seconds respectively (n=8) (Figure 10). The mean backward speed of the males at 2, 4 and 6 metres was 0.58 + 0.03, 1.08 + 0.08 and 1.51 + 0.10 seconds respectively (n=8) (Figure 11). The mean forward speed of the females at 2, 4 and 6 metres was 0.49 + 0.05, 0.87 + 0.08 and 1.25 + 0.09 seconds respectively (n=7) (Figure 10). The mean backward speed of the females at 2, 4 and 6 metres was 0.64 + 0.06, 1.20 + 0.06 and 1.74 + 0.10 seconds respectively (n=7) (Figure 11). The greatest distance one would have to cover on the badminton court is that of 7m, which would be diagonally from corner to corner. Footwork from the base to any corner would cover an approximate distance of 2 – 3m and footwork from the back to the front in a straight line would cover an approximate distance of 4 - 5m. The forward speed is faster than the backward speed for both the males and females in this study. This corresponds with Omosegaard (1996) who states that the speed on court is generally faster when going to the shuttle (6.8km/hr) than when returning to the playing centre (5.5km/hr). Speed is needed on court in moving to and from the shuttle, and due to the nature of the game and the size of the court, it is important for the badminton player to reach his/her maximum speed as fast as possible. The players would be at an advantage if both their forward and backward speed were quick. The greater the on-court speed of a player, the quicker the player can intercept the shuttle, and the greater the intensity and pace of play that can be forced on the opponent.

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4.6

FLEXIBILITY

Within the realm of sport, there are many activities where high degrees of flexibility in specific joints are desirable for enhanced performance in both quantitative and qualitative athletic activities (Maud and Foster, 1995). According to MacDougall et al. (1991), flexibility is relevant to jumping, swimming, racquet and most team sports. The flexibility data collected during the fitness testing are reported in Table 5 and Table 6.

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TABLE 5 Flexibility of the elite junior male (n=8) badminton players. Movement

Mean

Range

(degrees) D shoulder flexion

188

174 – 200

D shoulder extention

51 – 82

D shoulder int. rot.

42 – 72

D shoulder ext. rot.

126

100 – 151

Lateral trunk flexion (R)

45 – 69

Lateral trunk flexion (L)

44 – 65

Trunk flexion

25 – 55

Trunk extention

21 – 39

L hip flexion

74 – 105

L hip extension

25 – 50

R hip flexion

74 – 97

R hip extension

27 – 45

R hip ext. rot.

24 – 50

L hip ext. rot.

20 – 60

Abbreviations:D,

dominant;

ext.,

external;

int.,

internal;

left;

right;

rot.,

rotation;

SD,

standard deviation.

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TABLE 6 Flexibility of the elite junior female (n=7) badminton players. Movement

Mean

Range

(degrees) D shoulder flexion

185

170 –193

D shoulder extention

21 – 80

D shoulder int. rot.

45 – 76

D shoulder ext. rot.

144

124 – 166

Lateral trunk flexion (R)

41 – 64

Lateral trunk flexion (L)

54 – 70

Trunk flexion

33 – 75

Trunk extention

10 – 61

L hip flexion

54 – 112

L hip extension

30 – 60

R hip flexion

101

56 – 125

R hip extension

30 – 55

R hip ext. rot.

20 – 55

L hip ext. rot.

32 – 55

Abbreviations:D,

dominant;

ext.,

external;

int.,

internal;

left;

right;

rot.,

rotation;

SD,

standard deviation.

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4.6.1 Shoulder flexion and extension

The mean shoulder flexion and extension values measured by the Leighton Flexometer of the dominant shoulder of the males in this study was 188 + 8 degrees for flexion, and 65 + 10 degrees for extension (n=8) (Table 5). The females had mean shoulder flexion and extension values in the dominant shoulder of 185 + 7 degrees for flexion, and 63 + 20 degrees for extension (n=7) (Table 6). These values are low compared to Leighton Flexometer normative flexion and extension values of 224 – 242 degrees for males and 243 – 261 degrees for females (Maud and Foster, 1995). They are also lower than mean flexion and extension values obtained in junior tennis players, whose values range from 203 - 213 degrees for 15 – 17 year old males and 215.0 – 219.4 degrees for 16 – 17 year old females (Elliot et al., 1989 and 1990). They are however higher than values obtained from healthy adults in Heyward (1998), where the range of motion is 150 - 180 degrees for flexion and 50 - 60 degrees for extension.

4.6.2 Shoulder internal and external rotation

The mean shoulder internal and external rotation values of the dominant shoulder of the males in this study was 55 + 11 degrees for internal rotation, and 126 + 17 degrees for external rotation (n=8) (Table 5).

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The females had mean shoulder internal and external rotation values in the dominant shoulder of 58 + 11 degrees for internal rotation, and 144 + 16 degrees for external rotation (n=7) (Table 6). In studies performed by Chandler et al. (1990) on elite junior tennis players, it was found that the dominant and non-dominant shoulder internal rotation value was 65 + 19 and 76 + 12 degrees respectively. The internal rotation values of the subjects in this study are lower compared to the elite junior tennis players, but the external rotation values are higher. These values however, are low compared to normative Leighton Flexometer shoulder internal and external rotation values of 172 – 192 degrees for males and 207 – 227 degrees for females (Maud and Foster, 1995).

4.6.3 Trunk lateral flexion

The mean trunk lateral flexion values of the males in this study was 60 + 7 degrees for lateral trunk flexion to the right, and 58 + 7 degrees for lateral trunk flexion to the left (n=8) (Table 5). The females had a mean trunk flexion to the right of 53 + 7 degrees, and a mean trunk flexion to the left of 60 + 7 degrees (n=7) (Table 6). These values are low compared to normative Leighton Flexometer lateral trunk flexion values of 90 – 106 degrees for males and 120 – 136 degrees for females (Maud and Foster, 1995). These values however, are higher than values obtained from healthy adults in Heyward (1998), whose values range from 25 – 35 degrees.

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4.6.4 Trunk flexion and extension

The mean trunk flexion and extension values of the males in this study was 43 + 10 degrees for flexion, and 32 + 7 degrees for extension (n=8) (Table 5). The females had mean trunk flexion and extension values of 53 + 17 degrees for flexion, and 38 + 18 degrees for extension (n=7) (Table 6). These values are low compared to normative Leighton Flexometer trunk flexion and extension values of 63 – 83 degrees for males and 48 – 68 degrees for females (Maud and Foster, 1995).

The trunk extension

values are higher than values obtained from healthy adults in Heyward (1998), where the range of motion is 20 - 30 degrees, but the flexion values are lower than the range of 60 – 80 degrees.

4.6.5 Hip flexion and extension

The mean hip flexion values of the males in this study was 85 + 10 degrees for the left hip, and 87 + 8 degrees for the right hip. The mean hip extension values was 36 + 9 degrees for the left hip, and 35 + 6 degrees for the right hip (n=8) (Table 5). The females had a mean hip flexion values of 93 + 19 degrees, with for the left hip, and 101 + 22 degrees for the right hip.

The mean hip

extension values was 42 + 11 degrees for the left hip, and 39 + 9 degrees for the right hip (n=7) (Table 6).

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The left and right hip flexion of the subjects in this study are higher compared to the elite junior tennis players, and are simialr to the average of the normative Leighton Flexometer flexion and extension values of 68 – 88 degrees for males and 100 – 120 degrees for females (Maud and Foster, 1995). The hip extension values however, are lower. The male flexion values are lower than, and the female flexion values are similar to the values obtained from healthy adults in Heyward (1998), where the range of motion is 100 - 120 degrees for flexion. Both the male and female extension values are higher than the values obtained in Heyward (1998), where the range of motion is 30 degrees for extension.

4.6.6 Hip external rotation

The mean hip external rotation values of the males in this study was 36 + 13 degrees for the left hip, and 39 + 9 degrees for the right hip (n=8) (Table 5). The females had mean hip external rotation values of 40 + 8 degrees for the left hip, and 44 + 14 degrees for the right hip (n=7) (Table 6). These values are low compared to the normative Leighton Flexometer hip rotation values of 100 – 119 degrees for males and 110 – 130 degrees for females (Maud and Foster, 1995). They are however similar to values obtained from healthy adults in Heyward (1998), where the range of motion is 45 - 50 degrees.

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4.6.7 Discussion

It is an advantage to have above average flexibility levels of the trunk and shoulder regions for racquet sports (Chin et al., 1995). This corresponds with Omosegaard (1996) who states that a greater flexibility of the trunk and stroke arm is undoubtedly an important factor, as well as hip and hamstring flexibility.

In badminton, above average flexibility of the

shoulder, trunk and hip is expected of players, as flexibility is important in reaching the shuttlecock, especially in stressful situations. High levels of flexibility are also needed so that the players are able to position themselves where they are able to hit the shuttlecock more powerfully (Nowak, 1998). The players in this study would be at a disadvantage as they have low levels of flexibility for the shoulder and trunk regions. Their hip flexibility however is average.

Omosegaard (1996) recorded that most right-

handed badminton players have a reduced flexibility of the right hip in comparison to the left hip, which is probably due to greater loads imposed on the right leg during the lunge jump, combined with inadequate stretching exercises. This however, was not found to be the case with the subjects in this study, as their right hip flexion scores were slightly higher compared to the left.

The results obtained in Omosegaard (1996)

correlates with studies performed by Chandler et al. (1990) on elite junior tennis players and athletes in sports predominantly using the lower body. It was found that the left and right hamstring values were 76 + 15 and 79 + 16 degrees respectively for the tennis players, and 80 + 17 and 80 + 16 degrees for the right and left hamstring of the other athletes.

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Adequate levels of flexibility would allow a player to perform the various strokes efficiently, as many retrievals are made with the spine and shoulder joint in hyperextension, and the hip and hamstrings fully flexed when lunge jumps are made at the net. It also allows for more fluent stroking when forced to stretch (Elliot et al., 1989) and facilitates agility on the court (Reilly et al., 1990).

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4.7

AGILITY

FIGURE 12 Agility (mean + SD) of males and females.

Abbreviations:n,

sample number;

SD,

standard deviation.

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n=7

12.5 12

n=8

Seconds

11.5 11 10.5 10 9.5

Males

Females

Mean

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The mean agility value for the males in this study was 10.7 + 0.5 seconds (n=8), and for the females was 11.9 + 0.4 seconds (n=7) (Figure 12). Compared to norms of college students in Johnson and Nelson (1986), the males and females in this study are advanced, as their values are below 10.72 for males and 12.19 for females. Agility is important for sports requiring rapid and precise changes of direction (Johnson and Nelson, 1986), and depends on the strength, endurance, speed, balance, visual processing, timing, reaction time, perception, anticipation and skill of the athlete. Agility is crucial to good court movement and correct positioning on the badminton court (Groppel and Roetert, 1992). Correct positioning on the court is essential in order to strike the shuttle effectively, and requires the use of the legs and feet. While the upper extremity uses the racquet to hit the shuttle, the lower extremity is responsible for getting the player in position to use the racquet. Agility is important to the badminton player due to the variation in the speed, height and angle of approach to the shuttle (Todd and Mahoney, 1995). In badminton, the ability to keep one’s balance while hitting a stroke depends on proper footwork, with an interplay of all the muscles of the body under the guidance of the labyrinth of the inner ear and vision (Izen, 1971). To be fast on a badminton court is not only a question of being in good physical condition or following the right tactics, but also taking into account technique and mental frame of mind (Omosegaard, 1996). Correct footwork technique is needed in order to be able to benefit reasonably from physical abilities gained, and to be able to move quickly and precisely to where the shuttle is, as efficiently as possible.

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CHAPTER FIVE:

5.1

CONCLUSION AND RECOMMENDATIONS

INTRODUCTION

Badminton is an intermittent sports activity characterised by long bouts of high intensity exercise interspersed with rest periods (Faccini and DalMonte, 1996). The game requires a combination of technical skill, strategy, mental acuity, experience and physical conditioning. Badminton players are required to have a good stroke production and physical fitness, as well as psychological characteristics that will enable successful performance.

In racket sports, the sport specific technical

skills are predominant factors. The physical fitness of a player, however, can be a decisive determinant of success during a tournament (Smekal et al., 2001). Chin et al. (1995), recommends that if a player wants to achieve reasonable success in international competition, improvements in physical fitness need to be emphasised in addition to skill training, in order to be able to compete effectively against stronger opponents. In order to compare young athletes’ performances at various levels, it is useful to build up a normative database of physical fitness components thought to be important in a particular sport (Elliot et al., 1989). Physiological profiling has been recommended in the popular literature by Groppel and Roetert (1992) for purposes of fitness assessment and developing norms, as well as for establishing a basis for longitudinal tracking.

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The test data obtained from physical fitness testing provides a good baseline and reference for coaches, sports physiologists, physiotherapists as well as future investigators, and the comparison of test scores of any one player with data from a normative base of many players enables strengths and weaknesses to be identified. This plays an important role in designing individual physical conditioning programmes according to sport specific demands, motivating players to train, and leads to the development of the players as well as the sport as a whole (Mahoney and Sharp, 1995). The physical fitness components important for the game of badminton that were studied and discussed include: body composition, aerobic ability, muscular characteristics, speed, flexibility and agility.

5.2

BODY COMPOSITION

Height is not a determinant of success in badminton (Reilly et al., 1990). Players with above average heights, however, may have an advantage in smashing and in intercepting the shuttle, forcing a more attacking form of play. The average heights of the male and female badminton players in this study are higher than the standard badminton net height, which is 1.52 to 1.55 metres from the floor.

Both the males and females are

therefore at an advantage, with the males having a greater advantage as they are on average approximately 20cm taller than the females.

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Body mass is a factor that has an influential role in sports requiring the repeated lifting of the body against gravity, such as in badminton. An increase in lean body mass will result in greater speed, strength and power without a loss of flexibility and agility. On average, both the male and female players have body mass values that are neither advantageous nor disadvantageous to their game. Individually however, there are some male and female players who would be at a slight advantage or disadvantage as their mass is lower or higher than average. The players in this study all had a body mass that corresponded closely with values obtained from other elite level racket sport players, hence their mass values are within the norms for racket sports. High levels of body fat are detrimental to performance for sports, such as badminton, as excess body weight as fat is disadvantageous in moving quickly around the court, as well as in jumping to strike the shuttle. Excess fat would also increase the energy expended in moving around the court. Lower levels of body fat will enhance the game of badminton as it permits a more effective gradient for the rapid transfer of heat produced during high intensity exercise. The male players have body fat percentages within the range required and would therefore not be at a disadvantage. The mean female value is also within the range, but could be lower for a more optimal advantage. Individually, some of the females would be at a greater advantage compared to the other players. The body fat percentages of the players, however, were within the norms for racket sport players, and would not negatively affect their performance.

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With regards to the somatotype of the players, both the male and female badminton players in this study are highest in their mesomorphic components. The endo and ectomorphic values were found to be similar, but slightly lower than the mesomorphic value. To gain an advantage in badminton, the players should preferably have a tall, lean and muscular build.

They would need to be high in their meso and ectomorphic

components, and low in their endomorphic component. Both the male and female players could be at a slight disadvantage due to the high endomorphic value. The height, mass, body fat percentage and somatotype of the players are all within normal ranges for racket sport players, and none of these variables would be a major hindrance to the success of the players.

5.3

AEROBIC POWER

In badminton, ninety percent of the energy demands associated with the repeated bursts of intense, brief activity are met by the anaerobic processes, but it is the aerobic metabolism that supplies the energy to enable the player to last for the duration of the match. Approximately 60 - 70% of the energy is derived aerobically and 30% anaerobically (Chin et al., 1995).

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The aerobic power values of both the males and females in this study were fairly low compared to top level, elite badminton and squash players. Their values tended to correspond more closely with that of tennis players, whose values, according to literature, tend to be lower than badminton, squash and handball players. This places the players at a disadvantage as they would not be able to keep up to the more intensive force of play by an opponent with a higher maximal oxygen consumption, they would not be able to endure the length and intensity of the matches as comfortably as they could, and their recovery rate would be slower. The maximal oxygen consumption values support the notion that aerobic fitness is necessary in badminton, but that high levels are not essential (Mahoney and Sharp, 1995).

However, it is recommended that the

badminton players in this study increase their aerobic fitness. This would greatly enhance their performance.

5.4

MUSCULAR CHARACTERISTICS

Omosegaard (1996) was able to measure the velocities and accelerations typical of each stage of play in badminton by means of high speed recordings.

The findings were that muscular power is used in

acceleration, during braking and pushing off, muscular strength for footwork at the playing centre and in connection with hitting the shuttle, speed for moving to and from the shuttle, dynamic endurance for the repeated push-offs in the corners and playing centre, and eccentric strength for braking when landing and pushing off.

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The muscular fitness requirements found to be important to the game of badminton, that were discussed and studied, include strength, power and endurance.

5.4.1 Strength

The absolute strength of the hamstrings and quadriceps of the dominant and non-dominant leg were similar for the males. The females had similar hamstring values for the dominant and non-dominant leg, but the absolute strength of the quadriceps was greater in the dominant leg compared to the non-dominant leg, but not significantly so. The relative strength of the hamstrings in both the dominant and nondominant legs was similar for both the males and females. The relative strength values of the quadriceps in the dominant leg in both the males and females, however, were found to be higher in the non-dominant leg. The hamstring:quadriceps ratios of both the males and females in this study were low, indicating that the hamstrings were not well proportionally developed. It is recommended that the players improve their hamstring strength so that correct ratios are developed in order to decrease the risk of knee injury. The absolute and relative eccentric strength of the quadriceps in the dominant and non-dominant legs was similar in both the males and females, and it was found that the relative eccentric strength of the quadriceps of both the dominant and non-dominant legs of the males and females in this study was lower than the concentric strength of the quadriceps.

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Due to the fact that eccentric strength is important for braking and pushing off in badminton, the players would be at a disadvantage as more time would be spent in braking and pushing off. This would be a disadvantage for players who use attacking tactics in their game, and it is recommended that the players in this study develop their eccentric strength in order to enhance their game. Badminton is strength-related rather than strength-limited. Low strength values would therefore not limit a player’s performance, but an increase in strength as a result of strength training would improve and enhance their performance to some degree.

It is therefore recommended that the

players in this study improve their leg strength, particularly their concentric hamstring strength and eccentric quadriceps strength.

5.4.2 Power

A vital aspect of a sport such as badminton is the ability of the player to exert muscular force at high speed and badminton at the highest level places a great demand on explosive power.

5.4.2.1 Leg power

Leg power is important in badminton as it results in the player being able to move quickly and explosively to the shuttle in various directions and to jump high to play overhead strokes.

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Greater leg power would result in greater acceleration and speed when lifting off the floor in moving or jumping to hit the shuttle. The vertical power values of the males and females in this study were low compared to that of other badminton players. The values correspond with and are higher than that of tennis players, but that would be expected due to the vertical nature of the game of badminton compared to tennis. The players would therefore be at a disadvantage as vertical power is important for jumping high to intercept the shuttle, and in the smash stroke for some players. A greater vertical power would result in a faster and more attacking game as the player would be able to intercept the shuttle sooner, and players who have mastered the technique of jumping to hit the smash would also be at an advantage as they would be able to create a steeper angle for the smash stroke, making it more difficult for the opponent to return. Horizontal power is important in taking lunge jumps to net shots.

greater horizontal power will result in the player being able to reach the shuttle more quickly, and thus force a faster pace of play. This power also helps in getting to un-anticipated shots, where an explosive movement to a relatively far distance has to be made quickly.

The

horizontal power values of both the males and females tended to have quite a large range. This means that there were a few players who had values within the optimal mean range, but that there were also players who were well below and higher than average, indicating that not all the players are at equal horizontal power levels. Due to the large range and low values obtained in the power tests, it is recommended that both the male and female players in this study improve their vertical and horizontal power.

This would result in a marked

improvement in their individual games.

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5.4.2.2 Arm power

The absolute and relative internal rotation power of the dominant arm was found to be higher than the external rotation power for both males and females in this study. This coincides with Chandler et al. (1992) who state that an increased strength in internal rotation tends to occur in sports where plyometric-type movements are used during the acceleration phase, such as in badminton.

Overhead forehand strokes require

explosive internal rotation power and are performed much more than the overhead backhand strokes, resulting in a greater internal rotation strength.

Players would be at a disadvantage if their internal rotation

power was low as they wouldn’t be able to clear or smash the shuttle as far and hard as someone with a greater power. The external rotation of the shoulder is used in the backswing of the stroke for overhead forehand strokes and for hitting the backhand clear. The external rotation for the backswing phase of overhead forehand strokes does not require explosive power, but the backhand clear does. Players with a higher external rotation power would be at an advantage as they would be able to have a more powerful backhand clear. The external:internal shoulder rotation ratios of the male and female players in this study are both high. The external rotators, even though weaker than the internal rotators, are therefore relatively strong and almost the same strength as the internal rotators. Both the males and females in this study have a healthy external:internal rotation ratio in their dominant shoulder, giving them an advantage.

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Due to the fact that the upper body can be strong and powerful enough simply from the nature of the sport, arm power is a characteristic that can be developed naturally by playing the sport and practising strokes on a regular basis.

5.4.3 Muscular endurance

Dynamic upper body endurance is important for badminton players due to the repetitive nature of striking the shuttle, and is a fitness component that can be developed naturally by participating in the sport. Players with a high upper body endurance ratio would be able to play more strokes without getting fatigued in the arms, and last longer during a match against an opponent with a lower arm endurance ratio. A high endurance ratio would also benefit players who smash and/or clear a lot during the game, as it would allow them to play their repetitive smashes or clears for a longer time before fatigue would set in. Well developed strength and endurance of the trunk muscles is also important for the badminton player, due to the large, repetitive and varied movements of the trunk during a game.

Abdominal endurance is

important as the muscles are involved in virtually every movement and stroke that happens on the badminton court. Without sufficient trunk development in terms of strength and endurance, strokes will lack power and control, and without sufficient upper body endurance development fatigue will set in and lead to a decrease in performance.

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The upper body and abdominal endurance of both the males and females can be improved and it is recommended that this component of physical fitness be developed further in order to enhance performance of the players.

5.5

SPEED

Speed is needed in badminton for moving to and from the shuttle, and the ability to cover short distances quickly is a great advantage for the badminton player. The greatest distance one would have to cover on the badminton court is that of 7m, which is diagonally from corner to corner. Footwork from the base to any corner would cover an approximate distance of 2 – 3m and footwork from the back to the front in a straight line would cover and approximate distance of 4 - 5m. Due to the nature of the game and the size of the court, reaching maximum speed as fast as possible is important for the badminton player. The forward speed was faster than the backward speed for both the males and females in this study. While performing the backward speed tests, it was noted that the players were clumsy and not sure of their backward running footwork. It is recommended that all players in this study develop their backward speed, as well as forward speed, by doing specific on- court speed training routines. The greater the on-court speed of a player, the quicker the player can intercept the shuttle, and the greater the intensity and pace of play that can be forced on the opponent.

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5.6

FLEXIBILITY

Badminton requires an above average flexibility of the shoulder, trunk and hip joint. This is due to the fact that flexibility plays an important role in retrieving shuttles, especially in stressful situations where limbs are stretched to the limit. An adequate level of flexibility allows a player to perform the various strokes efficiently, as many retrievals are made with the spine and shoulder joint in hyperextension, and with the hip and hamstrings fully flexed, when lunge jumps are made at the net. For most of the flexibility components measured, the results of both the male and female subjects in this study were low in comparison to other athletes, and it is recommended that the badminton players incorporate flexibility training into their training programmes to improve their flexibility. A greater flexibility would result in improved maximal strength, a greater ability to utilise the stretch-shorten cycles effectively, augmented efficiency, a decreased risk of injury and correct movement patterns through the required range of motion.

It would result in more fluent

stroking when forced to stretch, and would facilitate agility on the court.

5.7

AGILITY

Agility is the ability to change direction quickly and precisely without a loss of balance. It is crucial to good court movement and correct positioning on the badminton court, and requires a combination of strength, speed, flexibility, and correct footwork technique.

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Correct positioning on the court is essential in order to strike the shuttle effectively, and requires the use of the legs and feet. While the upper extremity uses the racquet to hit the shuttle, the lower extremity is responsible for getting the player in position to use the racquet. Agility is important to the badminton player due to the variation in the speed, height and angle of approach to the shuttle. Both the males and females in this study were advanced in their agility performance compared to the normative data for the test.

While

performing an unrecorded shadow badminton test it was noted that some of the players were unsure of their footwork and did not have correct footwork as such. Correct footwork technique is important in order to be able to benefit reasonably from physical abilities gained, and to be able to move quickly and precisely to where the shuttle is as efficiently as possible.

It is therefore recommended that the players do footwork

training with speed as much as possible in order to improve their agility further and enhance their game.

5.8

SUMMARY

The physical fitness of a badminton player can be the decisive determinant of success during a tournament, and if a player wishes to achieve success in international competition, improvements in physical fitness needs to be emphasised.

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The physical fitness components of the players in this study that formed a weakness, and needs to be greatly improved, includes their aerobic power, leg power and flexibility.

Other fitness areas that are not

necessarily a weakness, but can be improved further, is their hamstring strength, eccentric leg strength, upper body and abdominal endurance, backward speed and agility. The test data obtained from this study provided a good baseline and reference for the individual players tested, the coaches of the elite junior team, as well as future elite junior players and coaches. It also enabled strengths and weaknesses within the group to be identified, so that appropriate training programmes could be designed to improve their performance.

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REFERENCES

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150

APPENDICES

Informed consent form.

Timetable and instructions for testing.

Data collection sheet.

SEMO agility test.

Sample of physical fitness evaluation report submitted to Badminton South Africa.

Sample of physical fitness evaluation report submitted to individual subjects.

151

APPENDIX A

Informed consent form

152

Badminton Research

INFORMED CONSENT In order to assess cardiovascular function, body composition, and other physical fitness components, the undersigned hereby voluntarily consents to engage in one or more of the following tests (tick the appropriate choices): ♦ ♦ ♦ ♦ ♦ ♦

Aerobic fitness tests _____ Body composition tests _____ Muscular fitness tests _____ Flexibility tests _____ Field tests _____ Time-motion video analysis _____

Explanation of the tests The aerobic test (Bleep test) requires continuous running (to the sound of a metronome) until exhaustion, or until symptoms dictate that we terminate the test. For body composition analysis, you will be required to take off as much clothing as possible (preferably a bikini for women and a Speedo for men, however, this isn’t compulsory) so that skin fold measurements can be taken. If the women would prefer a female to do the skinfold measurements, it can be arranged. The same would apply to the men. This provides an accurate assessment of your body composition. For muscular fitness testing, you will be tested by the Cybex (variable resistance) machine, which will assess the strength of your quadriceps and hamstring muscles, as well as the power endurance of your dominant arm shoulder muscles. You will also be doing push-ups (as many as you can in 1 minute) and sit-ups (as many as you can in 2 minutes) to determine your abdominal and upper body muscular endurance. For the evaluation of flexibility, you perform a number of movements so that we can measure the range of motion in your joints. The following field tests will be conducted: - speed, explosiveness (vertical jump test and lunge jump test), explosiveness/agility (shadow badminton test) and an agility test. The speed test requires that you sprint as fast as you can for a distance of 30 meters both forwards and backwards. The vertical jump test requires that you jump up as high as you can, and the lunge jump test requires that you lunge jump as far forward as you can. The shadow badminton test requires that you move about the badminton court in a specific sequence as fast as you can, and the SEMO agility test requires that you run in a set pattern as fast as you can. The time motion video analysis involves being video recorded for all of your competitive singles games in the first tournament of the season and at the South African Championship tournament at the end of the season. This is so that the number of winning and losing strokes can be determined so that appropriate training programmes can be designed. It also requires that you wear a downloadable Polar heart rate monitor (which will be provided) so that the intensity of the games can be recorded. This will also help with the prescription of badminton specific training programmes.

153

Risks and discomforts During the bleep test, certain changes may occur. These include abnormal blood pressure responses, fainting, irregularities in heartbeat, or heart attack. Every effort is made to minimize these occurrences. Emergency equipment and trained personnel are available to deal with these situations if they occur. You may experience discomfort with the skinfold measurements, but it will only be momentarily as a measurement lasts for 3 seconds. There is a slight possibility of pulling a muscle or spraining a ligament during the field tests, muscular fitness and flexibility testing. Performing warm-up exercises prior to taking the tests can minimize these risks. If muscle soreness occurs, appropriate stretching exercises to relieve this soreness will be demonstrated. You may experience some discomfort with wearing a heart rate monitor at first, but this normally doesn’t last long as you get used to the feel of it. Expected benefits from testing These tests allow us to assess your physiological working capacity and to appraise your physical fitness status. The results will be used for research purposes so that appropriate training programmes can be designed. Records are kept strictly confidential unless you consent to release this information. Both the experimental and control group players will receive results of the testing, however, only the experimental group players will receive a training programme that will be specifically designed to improve on court performance. Inquiries Questions about the procedures used in the physical fitness tests are encouraged. If you have any questions or need additional information, please ask me to explain further. Freedom to consent Your permission to perform these physical fitness tests is strictly voluntary. You are free to stop the test at any point, if you so desire. I have read this form carefully and I fully understand the test procedures that I will perform and the risks and discomforts. Knowing these risks and having had the opportunity to ask questions that have been answered to my satisfaction, I consent to participate in these tests. ________________________ Date

_____________________________________ Signature of player

________________________ Date

_____________________________________ Signature of parent or guardian

________________________ Date

_____________________________________ Signature of researcher 154

APPENDIX B

Timetable and instructions for testing

155

BADMINTON RESEARCH

Timetable Date

Time

Tests

Friday 28th June

08:00 – 12:00

Anthropometrics

12:00 – 13:00

Lunch

13:00 – 18:00

Flexibility

08:00 – 12:00

Field tests

12:00 – 13:00

Lunch

13:00 – 17:00

Arm power-endurance

08:00 – 12:00

Leg strength (Cybex)

12:00 – 13:00

Lunch

13:00 – 18:00

Leg strength (Cybex)

Saturday 29 June

Sunday 30th June

Specific instructions to ensure maximum results Wear comfortable clothes i.e. badminton takkies, shorts and shirt. You may wear a tracksuit but ensure that you have shorts with you. Get enough sleep the night before each testing day (very important). Ensure you have lots of fluids and food the day before testing. Ensure that you bring enough fluids with you during the testing (water or sports drink). Do not do any strenuous exercise the day before the testing or on the day of testing. Do not consume any food, caffeine or fluids 3 hours prior to testing. No alcohol the day before and during testing – it will lead to dehydration and poor results.

Please abide by these rules, as a failure to do so will jeopardise the results of the research.

156

APPENDIX C

Data collection sheet

157

BADMINTON RESEARCH Fitness Performance Evaluation Name: Dominant hand:

Body Composition 1 Age Height Mass

Triceps Subscapula Supraspinale Abdominal Frontal thigh Medial calf Biceps

Upper arm tensed Calf circumference Humerus girth Femur girth Field Tests Aerobic power Bleep test Speed (secs) Forward

Flexibility

Vertical jump (cm)

Lunge jump (cm)

Static

Backward

2m 4m 6m 2m 4m 6m

Explosive power

D shoulder flex D shoulder ext Lateral trunk flex (R) Lateral trunk flex (L) Trunk flex. Trunk ext. D shoulder int. rot. D shoulder ext. rot L Hip flex. L Hip ext. R Hip flex. R Hip ext. R hip ext.rot L hip ext.rot

Dynamic Total

Shadow badminton (secs)

Agility SEMO test (secs)

Muscular endurance Push-ups in 1 min Sit-ups in 2 min

158

APPENDIX D

SEMO agility test

159

SEMO agility test

Start A

3.60m

5.77m

Finish

160

APPENDIX E

Sample of physical fitness evaluation report submitted to Badminton South Africa

161

JUNIOR NATIONAL BADMINTON SQUAD PHYSICAL FITNESS EVALUATION REPORT

1 2 3 4 5 6 7 8

Males (Name) (Name) (Name) (Name) (Name) (Name) (Name) (Name)

Males Age Height (cm) Mass (kg) Females Age Height (cm) Mass (kg)

1 2 3 4 5 6 7

1 16 177.9 59.3 1 14 157.9 53.3

2 16 182.8 73.3 2 15 155.9 45

3 17 170.5 67.8 3 16 168 67

Females (Name) (Name) (Name) (Name) (Name) (Name) (Name)

4 17 167.5 67.1 4 16 160.2 59.2

5 18 185.7 76.9 5 15 160.8 58.3

6 17 180.6 69.7 6 17 165.9 67.9

7 16 188.6 86.7 7 17 160 55.9

8 16 189.9 86.8

Ave 17 180.4 73.4 Ave 16 161.2 58.1

5 10.1 23.7 5 75.5 141.3

6 7 8.8 8.4 21.7 22.6 6 7 62.6 61.3 127.1 130.4 Range 37.1 – 72.3 60.8 – 146.4

Ave 10.1 19.2 Ave 82.5 71.5 108.8 Average 53.4 101.2

5 3 3.2 3.4 5 5.2 2.8 1.8

6 2.6 4.4 3.6 6 5.4 5.2 1.2

8 3.4 3.1 2.9

BODY COMPOSITION RESULTS Body fat % Males Females Sum of 7 Skinfolds Males Females

1 7.1 18.4 1 46.4 101.5

2 11.3 10.9 2 87.7 51.7

3 8.8 21.1 3 63.6 122.5

4 11.8 16.1 4 92.7 87.3

Sum of 7 Skinfolds of National junior Australian players (males) Sum of 7 Skinfolds of National junior Australian players (females) Males Endomorphy Mesomorphy Ectomorphy Females Endomorphy Mesomorphy Ectomorphy

1 2 2.6 4.9 1 4.5 3.9 2.2

2 4.7 3.7 3.4 2 2 3 3.5

Somatotype 3 2.9 4.8 2.1 3 4.9 4.9 1.7

4 4.1 5 1.6 4 3.9 5.8 1.6

7 3 5.6 2.7 7 5.2 4.4 2.1

8 10.7

162

Ave 3.2 4 3.1 Ave 4.4 4.3 2

Comments: With regards to the body fat percentages, (Name) and (Name) values are a bit low. They both need to gain 2 kg’s to be at an optimal weight. The rest of the boys’ values are fine, as the average fat % for male badminton players should range between 10 and 15%. The average values for female badminton players should range between 15 and 20 %. If the value is higher than 25% it is a bit too high and disadvantageous for the player. (Name) is the only female who should be careful of fatty food intake. It would be advantageous for her badminton if she lost 3kg. The Somatotype value gives you an indication of the players general body shape. The endomorphic component refers to the relative fatness, the mesomorphic component refers to the relative muscle robustness, and the ectomorphic component refers to the relative linearity or “tall thinness”. The highest value you can obtain for each of these components is 8. The values the players are highest in show you what component they are predominant in and gives you an indication of their general shape. If they are high in their ecto and mesomorphic component, it shows you that they are tall/thin but have a lot of muscle. If they are high in the endo and mesomorphic component, it shows that they are muscular and “fat” and not tall and lean. For badminton players, it would be advantageous if you were predominant in the ecto and mesomorphic components.

FLEXIBILITY RESULTS Key: A B C D E F G

Shoulder flexion (playing arm) Shoulder extension (playing arm) Lateral trunk flexion (to the right) Lateral trunk flexion (to the left) Trunk flexion Trunk extension Shoulder internal rotation (playing arm)

H I J K L M N

A B C D E F G H I J K L M N

Average value for males 188 65 60 58 43 32 55 126 85 36 87 30 33 29

Shoulder external rotation (playing arm) Left hip flexion Left hip extension Right hip flexion Right hip extension Right hip external rotation Left hip external rotation

200 62 69 63 38 22 50 144 87 45 97 33 40 37 10/14

183 51 57 61 36 35 61 135 74 25 74 27 41 27 6/14

184 70 65 65 25 35 67 125 105 38 91 39 24 23 9/14

193 63 62 56 48 29 72 100 97 39 94 30 35 20 9/14

189 54 55 55 52 39 42 123 80 27 86 33 30 35 5/14

186 82 61 58 44 36 56 151 80 35 82 34 45 40 10/14

193 74 64 64 43 35 44 122 80 50 94 45 50 60 11/14

174 65 45 44 55 21 46 107 80 32 80 40 50 46 5/1

163

A B C D E F G H I J K L M N

Average value for females 185 63 53 60 53 38 58 144 93 42 101 39 44 40

189 65 50 56 50 45 45 135 103 40 107 31 54 37 6/14

190 66 56 64 41 28 50 164 54 37 56 40 52 44 8/14

193 80 41 56 72 27 70 124 90 30 106 33 54 32 6/14

187 60 64 54 75 54 50 166 103 50 97 45 41 35 8/14

184 21 55 67 39 43 55 140 87 45 125 40 31 45 8/14

170 66 50 55 33 10 76 132 104 30 100 30 20 35 4/14

185 80 55 70 61 61 61 144 112 60 115 55 55 55 14/14

Comments: The most important flexibility components for badminton players are the flexibility of the hip, hamstrings, trunk and shoulder of the playing arm. All of these components were measured. Boys flexibility: (Name), (Name) and (Name) have above average flexibility values for 10 and 11 of the 14 flexibility components. (Name) and (Name) have above average flexibility values for 9 of the 14 components; and (Name), (Name) and (Name) only have above average flexibility values for 5-6 of the flexibility components, which is quite poor. Girls flexibility: (Name) has excellent flexibility in that her values are above average for each of the flexibility components. (Name), (Name) and (Name) have above average values for 8 out of the 14 components, and (Name), (Name) and (Name) have only above average values for 6,6 and 4 out of the 14 components respectively. Each player, irrespective of their flexibility results, can benefit greatly by stretching on a daily basis, even if they aren’t training for the day. The muscles that need to be stretched are the hamstrings, gluteus (backside), quadriceps, calf, trunk, shoulder internal and external rotators, and the shoulder flexors and extensors.

FIELD TESTS RESULTS MUSCULAR ENDURANCE

Push-ups in 1 minute Sit-ups in 2 minutes

Average for males 28 56

Push-ups in 1 minute Sit-ups in 2 minutes

Average for females 40 57

19 45

27 50

26 50

27 61

30 70

37 55

35 49

23 68

34 59

37 33

45 81

40 50

37 60

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Comments: Upper body endurance is important in badminton due to the repetitive movements of the arm in playing strokes at high or maximum speed. The abdominal muscles are very important in badminton as they play an important stabilising function and they are involved in all movements and stroke production on a badminton court. It would be beneficial for all players if they did 3 sets of 20/25/30 sit-ups/crunches (depending on capability) at least 3 times a week (or preferably every day) as well as 2 sets of as many push-ups as possible 3 times a week or every day. Boys: (Name), (Name) and (Name) have good upper body endurance; and (Name), (Name) and (Name) have an average upper body endurance. (Name) and (Name) upper body endurance is a bit poor and needs to be developed. (Name), (Name) and (Name) have a good abdominal endurance; (Name) an average upper body endurance, and (Name), (Name), (Name) and (Name) need to develop their abdominal endurance. Girls: (Name), (Name) and (Name) all have a good upper body endurance; and (Name) and (Name) have an average upper body endurance. (Name) upper body endurance needs to be improved. (Name), (Name) and (Name) all have a good abdominal endurance, and (Name) and (Name) abdominal endurance needs to be developed. Overall, (Name) and (Name) were the only players to have above average values for both their upper body and abdominal endurance. AGILITY

SEMO test Shadow badminton test

Average for males (in sec’s) 10.7 9.2

SEMO test Shadow badminton test

Average for females (in sec’s) 11.9 10.2

11.1 9

10.5 9.5

10.4 9.1

10.1 9.0

11.3 9.6

10.2 9.1

10.6 8.8

11.6 9.8

12.4 10.3

11.3 9.9

12.2 11

11.4 10.1

11.9 10.3

12.1 9.8

Comments: Speed and agility on a badminton court is a combination of technique, tactics, physique, and mental frame of mind. Good footwork technique is necessary in order to benefit from physical abilities trained, attacking tactics is better as it brings out the speed in a player, and explosive strength is an important physical fitness component that needs to be developed for enhanced speed and agility on the court. To move quickly on a badminton court is a question of accelerating, braking and changing direction as fast as possible, so it is necessary for each player to practice speed work that involves short distance stop/start fast movements that are badminton related with regards to footwork. It was observed during the shadow badminton test that footwork technique was lacking in most of the players, especially the girls. (Name) is the only player who achieved a good fast time. On the other hand, (Name) didn’t have a particular footwork technique as such, yet she achieved the fastest time for the test. If she had correct footwork she could possibly be even faster. The rest of the players were either at the average or lower than average. (Name) lacked concentration with his footwork – he had to restart the test quite a few times.

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EXPLOSIVENESS

Vertical jump Lunge jump

Average for males (in cm) 53 40

Vertical jump Lunge jump

Average for females (in cm) 35 42

57 69

54 22

56 53

49 37

54 32

56 40

53 60

46 10

33 24

45 34

37 49

26 17

39 83

31 43

Comments: As noted with the agility results, explosiveness is important for speed and agility on court, and each player would benefit greatly by specifically including explosiveness training into their training programmes. From literature, elite male badminton players jump a height of 65-75cm, national badminton players a height of 60-70cm, and league players a height of 55-65cm. Most of the boys are at the league level with regards to their jumping height but there is still room for improvement. (Name) and (Name) values are quite low, and this is a component that they need to work on. According to literature on female badminton players, elite women jump a height of 52-62cm, national players a height of 48-55cm and league players a height of 45-55cm. (Name) is the only female who obtained a high score for the vertical jump, with (Name) and (Name) being above average with regards to the group results. (Name) value is poor and her vertical jumping height explosiveness needs to be developed. The lunge jump values give you an indication of the players’ ability to brake – their eccentric strength (keeping in balance) and than push-off again with enough strength to get them back to where they started. (Name), (Name), (Name), (Name) and (Name) obtained good results with (Name) doing exceptionally well. The players that need to work on their explosiveness with regards to braking and pushing off from a lunge are (Name), (Name), (Name), (Name) and (Name). AEROBIC POWER

VO2max

Average for males (ml/min/kg) 51

VO2max

Average for females (ml/min/kg) 42

51.1

49.7

54.6

48.7

54.8

48.7

46.3

51.4

40.8

39.9

44.2

41.1

39.2

47.1

41.5

Comments: The VO2max value gives you an indication of the players’ ability to consume and utilise oxygen while doing exercise. The multistage fitness test gives you an average estimate of the general fitness level of the player. The test was used for 3 reasons: It is a sufficiently accurate estimate of aerobic power, the activity is similar to badminton with respect to the stop, start and change –of-direction movement patterns, and it is a time-efficient test in that a whole squad can be assessed at the same time.

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(Name), (Name), (Name), (Name), (Name) and (Name) all have above average VO2max values. The rest of the players are below average. The VO2max of a player is not a fitness parameter that can be improved to a large degree as it has a genetic ceiling. It can be improved by approximately 5% - 30% by doing medium to high intensity aerobic training. SPEED

Forward 2m 4m 6m Backward 2m 4m 6m

Ave for males (sec’s)

0.44 0.80 1.14

0.48 0.73 1.14

0.48 0.83 1.17

0.42 0.8 1.11

0.42 0.83 1.14

0.39 0.78 1.11

0.42 0.77 1.08

0.46 0.8 1.15

0.42 0.87 1.23

0.58 1.08 1.51

0.55 0.98 1.42

0.58 1.08 1.55

0.55 1.02 1.45

0.58 1.12 1.48

0.55 1.02 1.42

0.58 1.05 1.48

0.58 1.11 1.56

0.64 1.23 1.73

Ave for

females (sec’s) Forward 2m

0.49

0.48

0.45

0.52

0.58

0.48

0.43

0.87

0.89

0.8

0.86

1.02

0.8

0.86

1.25

1.2

1.18

1.23

1.42

1.2

1.25

Backward 2m 4m 6m

0.64 1.20 1.74

0.56 1.18 1.73

0.67 1.17 1.67

0.67 1.27 1.86

0.73 1.27 1.83

0.59 1.14 1.58

0.64 1.17 1.77

Comments: As mentioned with agility, speed is a question of accelerating and braking as fast as possible. The acceleration phase of the test is the time at the 2 and 4 metre marks, which is the more likely the distance to be covered for most shots on the badminton court. The faster the acceleration, the faster you are able to reach the shuttle, and the less time there is available for the opponent to recover and get into position for the next shot. To be faster on the court would benefit a player who uses attacking tactics as opposed to defensive tactics. (Name) and (Name) have the fastest acceleration time at the 2-metre mark in moving forward, which is beneficial in moving to the front corners from the base. (Name) also has the fastest time, along with (Name) and (Name) for running backward, as in from the base to the back corners. (Name) has the fastest time for moving backward to the 2 metre mark of the girls. (Name) and (Name) need to develop their acceleration speed in running both forwards and backwards.

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CYBEX TESTING RESULTS Key: A B C D

Quadriceps strength as a % of Body weight Hamstring strength as a % of Body weight Ave power of quadriceps as a % of Body weight Ave power of hamstrings as a % of Body weight

LEG STRENGTH (MALES) Dominant leg: A B C D

Average 286.3 178.6 188.3 113.6

1 274.6 171.2 168.7 103.3

2 224.7 152.1 147.7 111.5

3 297 174.6 166.4 83.4

4 292.5 201.5 193.6 137.4

5 269.7 182.9 178.1 121.5

6 333.3 182.6 240.6 130.1

7 362.8 180.2 262.6 115.8

8 236 183.7 148.6 106

2 287.7 149.3 174.9 108.3

3 247.8 170.1 160.7 89.7

4 188.1 191 178.9 125.7

5 284.2 180.3 191.1 132.9

6 295.7 175.4 209.9 133.4

7 360.5 183.7 267.1 122.4

8 277.9 173.3 171.3 108.5

Non-dominant leg: A B C D

Average 277.7 182.6 192 116.4

1 279.7 237.3 181.8 109.9

LEG STRENGTH (FEMALES) Dominant leg: A B C D

Average 259.6 154.6 167.7 105.8

2 248.9 146.7 187 104.1

3 271.6 161.2 174 104.4

4 237.3 169.5 153.1 117.2

6 291.1 159.1 172.8 110.2

7 249.1 136.4 151.7 93.3

1 211.3 134 149.9 88.3

2 224.4 146.7 163.3 86.4

3 243.3 159.7 169.4 109

4 228.8 167.8 150.3 117.4

5 210.3 174.1 149.4 92.8

6 309.2 142.8 190.9 95.3

7 241.8 123.6 175.6 76.9

Non-dominant leg: A B C D

Average 238.4 149.8 164.1 95.2

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Comments: Of the males (Name), (Name) and (Name) have above average results for the leg strength tests, which is very good. With regards to the individual results, (Name) and (Name) are the only players who have “perfect” hamstring: quadriceps ratios. Having the correct hamstring: quadricep ratio is important, as it will decrease the chance of the player getting a knee injury. (Name) needs to focus on increasing his right hamstring strength; (Name), his right and left hamstring as well as his right quadricep; (Name) his right and left hamstring as well as his right quadricep; (Name) the strength of both hamstrings as well as his left quadricep; (Name) the strength of both his hamstrings; and (Name) the strength of his hamstring and quadricep of his right leg – in order to correct the hamstring: quadricep ratios. As it can be seen, for most players the hamstring strength is lacking. Of the females, (Name) and (Name) are the only players who have above average values for most of the components. With regards to the individual results, (Name) is the only player with a “perfect” hamstring: quadricep ratio in both her legs. Unfortunately (Name) and (Name) could not do the tests on their right leg, but their left leg ratios are also fine. (Name) needs to increase the strength of the hamstrings in both her legs; (Name) her right hamstring; (Name) her right hamstring and left quadricep; and (Name) the hamstrings of both her legs. As with the males, for some of the players it is the hamstring strength that is lacking. Lunging exercises should help increase the hamstring strength in the players. ARM POWER Key: A B

Average power as a % of body weight of the external rotators Average power as a % of body weight of the internal rotators

A B

Average for males 60 85.1

A B

Average for females 46.8 55.3

40.6 71.3

45.8 90.2

40 48.6

80.7 91.7

70.6 99.8

74.8 100.2

79 103.2

48.7 76

60.8 56.2

24.4 35.3

46.9 60.1

53.3 61.7

51.3 46

48.9 80.7

42.1 47

Comments: Of the males; (Name), (Name), (Name) and (Name) all have above average power values for shoulder internal and external rotation. (Name) has very poor power values; and (Name), (Name) and (Name) have below average values. Of the females; (Name), (Name), (Name) and (Name) all have above average values for shoulder internal and external rotation. (Name) has very poor values, and (Name) and (Name) have below average values. With regards to the shoulder external: internal rotator ratio, a 2:3 ratio is the norm for badminton players. To have correct shoulder external: internal ratios; (Name) needs to increase his external rotation strength; and (Name), (Name) and (Name) need to increase their internal rotation strength. (Name), (Name), (Name) and (Name) have good ratios. Of the females (Name), (Name), (Name) and (Name) all need to increase their internal rotator strength. (Name), (Name) and (Name) ratios are good.

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APPENDIX F

Sample of physical fitness evaluation report submitted to individual subjects

170

JUNIOR NATIONAL BADMINTON SQUAD PHYSICAL FITNESS EVALUATION REPORT

Name Age Height (cm) Mass (kg)

16 188.6 86.7

BODY COMPOSITION RESULTS The average body fat % values obtained for the males in this study was Your body fat % average is The average value of the national junior Australian male badminton players is And the range of these players is Your value compared to the Australian badminton players is

10 % 8.4% 53,4 mm 37,1-72,3 mm 61.3mm

Comments: The average body fat % values for male badminton players should range between 10 and 15 %. Your value is slightly lower than the average but is nothing to worry about.

FLEXIBILITY RESULTS Movement Shoulder flexion (playing arm) Shoulder extension (playing arm) Lateral trunk flexion (to the right) Lateral trunk flexion (to the left) Trunk flexion Trunk extension Shoulder internal rotation (playing arm) Shoulder external rotation (playing arm) Left hip flexion Left hip extension Right hip flexion Right hip extension Right hip external rotation Left hip external rotation

Average value for females 185.4 63 53 60 53 38 58 144 93 42 101 39 44 40

Average value for males 188 65 60 58 43 32 55 126 85 36 87 30 33 29

Your value 193 74 64 64 43 35 44 122 80 50 94 45 50 60

Comments: The highlighted flexibility values are your flexibility values that are higher than average – that are good. The muscles that need extra flexibility training are your shoulder internal and external rotator muscles and your left hamstring. Your badminton would benefit greatly if you stretched on a daily basis, even if you aren’t training for the day. The muscles that need to be stretched are the hamstrings, gluteus (backside), quadriceps, calf, trunk, shoulder internal and external rotators, and the shoulder flexors and extensors.

171

FIELD TESTS RESULTS MUSCULAR ENDURANCE Push-ups in 1 minute Sit-ups in 2 minutes

Average for males 28 56

Average for females 40 57

Your value 35 49

SEMO test Shadow badminton test

Average for males (in seconds) 10.7 9.2

Average for females (in seconds) 11.9 10.2

Your value (in seconds) 10.6 8.8

Comments: Speed and agility on a badminton court is a combination of technique, tactics, physique, and mental frame of mind. Good footwork technique is necessary in order to benefit from physical abilities trained, attacking tactics is better as it brings out the speed in a player, and explosive strength is an important physical fitness component that needs to be developed for enhanced speed and agility on the court. To move quickly on a badminton court is a question of accelerating, braking and changing direction as fast as possible, so it is necessary to practice speed work that involves short distance stop/start fast movements that are badminton related with regards to footwork. Both your agility results in the SEMO and shadow badminton test are higher than average as the results are faster. To maintain these results, do as much shadow badminton training as possible to improve your agility on court. Your badminton will benefit greatly from it. EXPLOSIVENESS

Vertical jump Lunge jump

Average for males (in cm) 53 40

Average for females (in cm) 30 40

Your value (in cm) 53 60

172

Comments: Explosiveness is important for speed and agility on court, and your badminton would benefit greatly if you included explosiveness training into your training programme. According to literature on male badminton players, elite men jump a height of 65-75cm, national players a height of 60-70cm and league players a height of 55-65cm. The lunge jump value gives you an indication of your ability to brake – your eccentric strength (keeping in balance) and your ability to push-off again with enough strength to get you back to where you started. Your vertical explosiveness result (vertical jump) is on par with the average. There is however, still a lot of room for improvement. Your horizontal explosiveness (lunge jump) is higher than average, which is very good. AEROBIC POWER Average for males ml/kg/min 51

Bleep test

Average for females ml/kg/min 42

Your value ml/kg/min 46.3

Comments: The VO2max value gives you an indication of your body’s ability to consume and utilise oxygen while doing exercise. The multistage fitness test gives you an average estimate of your general fitness level and not the exact VO2max value as it does not take into account your body weight. This aspect of fitness is limited in that your body can only consume and utilise a specific amount of oxygen, which means that it is a fitness component that cannot be improved to a large degree. It can only increase by about 5-30% by doing aerobic training at a medium – high intensity. SPEED Ave for males (sec’s)

Ave for females (sec’s)

Your Average (sec’s)

0.44 0.8 1.14

0.49 0.87 1.25

0.46 0.8 1.15

0.58 1.08 1.51

0.64 1.20 1.74

0.58 1.11 1.56

Forwards 2m 4m 6m Backwards 2m 4m 6m Comments: Speed is a question of accelerating and braking as fast as possible. The acceleration phase of the test is the time at the 2 and 4 metre marks, which is the distance more likely to be covered for most shots on the badminton court. The faster the acceleration, the faster you are able to reach the shuttle, and the less time there is available for the opponent to recover and get into position for the next shot. To be faster on the court would benefit a player who uses attacking tactics as opposed to defensive tactics.

173

CYBEX TESTING RESULTS LEG STRENGTH (MALES)

Quadricep strength as a % of Body weight Hamstring strength as a % of Body weight Ave power of quadriceps as a % of Body weight Ave power of hamstrings as a % of Body weight

Average values Dominant Non-dominant Leg leg 286.3 277.7

Your values Dominant Non-dominant leg leg 362.8 360.5

178.6

182.6

180.2

183.7

188.3

192

262.6

267.1

113.6

116.4

115.8

122.4

Comments: The difference in strength of your quadriceps of your left and right leg and hamstrings of your left and right leg are minimal and nothing to be concerned about. The only strength issue that needs to addressed is that the hamstrings of your left and right leg need to have extra training so as to have a correct hamstring and quadricep ratios in both your legs. The hamstring/quadricep ratio is important as you are more likely to experience knee injuries if the ratio is out of balance Compared to the averages of the group, the highlighted values are the values that are above average – that are good. ARM POWER Average values Average power of external rotators as a % of Body weight Average power of internal rotators as a % of Body weight

Males 60 85.1

Your value

Females 46.8 55.3

79 103.2

Comments: Arm power is a combination of strength and speed – to be able to hit the shuttle hard at a fast speed is what is desired of badminton players. Both your external and internal rotation power values are above average. With regards to your external:internal shoulder rotation ratio, your value should be 40:60. Yours is 43:57, which means that you need to slightly increase the strength of your internal rotators.

174