Physiological responses and energy expenditure during competitive fencing

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Physiological responses and energy expenditure during competitive fencing Raffaele Milia, Silvana Roberto, Marco Pinna, Girolamo Palazzolo, Irene Sanna, Massimo Omeri, Simone Piredda, Gianmario Migliaccio, Alberto Concu, and Antonio Crisafulli

Abstract: Fencing is an Olympic sport in which athletes fight one against one using bladed weapons. Contests consist of three 3-min bouts, with rest intervals of 1 min between them. No studies investigating oxygen uptake and energetic demand during fencing competitions exist, thus energetic expenditure and demand in this sport remain speculative. The aim of this study was to understand the physiological capacities underlying fencing performance. Aerobic energy expenditure and the recruitment of lactic anaerobic metabolism were determined in 15 athletes (2 females and 13 males) during a simulation of fencing by using a portable gas analyzer (MedGraphics VO2000), which was able to provide data on oxygen uptake, carbon dioxide production and heart rate. Blood lactate was assessed by means of a portable lactate analyzer. Average group energetic expenditure during the simulation was (mean ± SD) 10.24 ± 0.65 kcal·min−1, corresponding to 8.6 ± 0.54 METs. Oxygen uptakeand heart rate were always below the level of anaerobic threshold previously assessed during the preliminary incremental test, while blood lactate reached its maximum value of 6.9 ± 2.1 mmol·L−1 during the final recovery minute between rounds. Present data suggest that physical demand in fencing is moderate for skilled fencers and that both aerobic energy metabolism and anaerobic lactic energy sources are moderately recruited. This should be considered by coaches when preparing training programs for athletes.

Key words: oxygen uptake, carbon dioxide production, blood lactate, heart rate, anaerobic threshold.

Résumé : L’escrime est un sport olympique dans lequel les athlètes s’affrontent avec des armes blanches. Une épreuve comprend 3 assauts de 3 minutes chacun avec 1 minute de repos entre les assauts. Il n’y a pas d’études traitant de la consommation d’oxygène et des exigences énergétiques durant les compétitions d’escrime; la dépense énergétique et les exigences énergétiques de ce sport ne sont encore que spéculatives. Cette étude se propose d’évaluer les capacités physiologiques durant une performance a` l’escrime. On évalue la dépense d’énergie en aérobiose et la sollicitation du métabolisme anaérobie lactique chez 15 athlètes (2 femmes, 13 hommes) au cours d’une simulation a` l’escrime en utilisant un analyseur de gaz portatif (MedGraphics VO2000) pour déterminer la consommation d’oxygène, la production de gaz carbonique et le rythme cardiaque. On évalue la concentration sanguine de lactate au moyen d’un analyseur de lactate portatif. La dépense énergétique moyenne au cours de la simulation est (moyenne ± écart-type) de 10,24 ± 0,65 kcal·min−1, soit 8,6 ± 0,54 METs. La consommation d’oxygène et le rythme cardiaque se situent toujours sous le seuil anaérobie évalué précédemment au cours d’un test d’effort progressif; la sanguine de lactate atteint une valeur maximale de 6,9 ± 2,1 mmol·L−1 durant la dernière minute de récupération entre les épreuves. D’après les résultats de cette étude, les exigences énergétiques de l’escrime sont modérées pour des escrimeurs compétents et les deux sources d’énergie, aérobie et anaérobie lactique, sont sollicitées modérément. Les entraîneurs devraient prendre en compte ces données au moment de préparer des programmes d’entraînement pour les athlètes. [Traduit par la Rédaction] Mots-clés : consommation d’oxygène, production de gaz carbonique, lactate sanguin, rythme cardiaque, seuil anaérobie.

Introduction Fencing is a combat sport between 2 athletes who fence each other using 1 of 3 types of weapon (the foil, the sabre, and the épée, each contested with different rules) and who are protected by specific fencing clothing, mask, gloves, and plastrons. Fencing is usually practiced indoors and requires skill, technique, and tactical excellence for success. The competition platform measures 14 m in length with a width of between 1.5 and 2 m. A judge presides over the bout with the aid of an electrical scoring apparatus connected to the target of the fencer (Roi and Bianchedi 2008). The International Federation of Fencing (Federation Internationale D’Escrime) claims 149 member countries worldwide. For instance, there are about 80 000, 60 000, 30 000, and 16 000 active

athletes in France, Germany, the United States, and Italy, respectively.

A fencing international tournament may last between 9 and 11 h. Bouts, during which each athlete is engaged in fighting, represent only about 18% of the total tournament time and, in this period, the effective fight time is between 17 and 48 min. Therefore, the length of dynamic phases is unpredictable, but is usually of short duration. Indeed, it has been reported that the duration of every action may be very short and intensive (less than 1 s) or it may last more than 60 s. Bouts are characterized by submaximal intensity preparatory movements, followed by intensive movements of short duration with the aim to touch the opponent (Roi and Bianchedi 2008; Roi and Pittaluga 1997). Taking into consideration these facts, energy requirements in fencing competitions

Received 26 May 2013. Accepted 16 September 2013.

R. Milia, S. Roberto, M. Pinna, G. Palazzolo, I. Sanna, A. Concu, and A. Crisafulli. Department of Medical Sciences, Sports Physiology Laboratory, University of Cagliari (Italy), Via Porcell 4, 09124 Cagliari, Italy.

M. Omeri and S. Piredda. National Italian Fencing Federation, Rome, Italy.

G. Migliaccio. Regional School of Sport of Sardinia, Italian Olympic Committee, Cagliari, Italy.

Corresponding author: Antonio Crisafulli (e-mail: crisafulli@tiscali.it).

Appl. Physiol. Nutr. Metab. 39: 324–328 (2014) dx.doi.org/10.1139/apnm-2013-0221

Published at www.nrcresearchpress.com/apnm on 26 September 2013.

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Milia et al.

can vary unpredictably, depending on the duration of both the preparatory and intensive phases. Therefore, from a physiological point of view, fencing appears to be an intermittent physically demanding sport, with short phases of maximal or supramaximal intensity spaced by recoveries. Hence, it is likely that both aerobic and anaerobic energy systems are recruited during a match.

To obtain an understanding of the physiological capacities underlying fencing performance it would be useful to know the energetic demand during a real fight. However, to the best of our knowledge, the energy requirement during a real fencing competition has never been studied. This information would provide benchmarks for the monitoring athletes’ training. This investigation was devised to study energetic demand during a fencing competition and to test the hypothesis that fencing is an activity that recruits both aerobic and anaerobic energy systems. In particular, we were interested in measuring aerobic energy expenditure during a competition and in discovering whether, and to what extent, anaerobic glycolysis is recruited. This information would allow coaches to design specific training programs able to induce the specific adaptations required by fencing.

Materials and methods Subjects Fifteen fencers (2 female, 13 male) that regularly participated in competitions over the last 4 years were enrolled. Mean ± SD of age, height, and body mass were 21.4 ± 6.9 years, 176.7 ± 10.6 cm, and 68.5 ± 12.9 kg, respectively. All subjects were skilled athletes who trained for 10–12 h a week and had been involved in regular training programs for at least 5 years. In the last year, 6 of them had participated in international competitions, while the other 4 in national tournaments. Thus, our group is representative of midupper level athlete fencers.

The study was performed in accordance with the Declaration of Helsinki and was approved by our local ethics committee (University of Cagliari). Written informed consent was obtained from all participants.

Experimental protocol Preliminary test All athletes underwent a preliminary incremental exercise test on a motorized treadmill (Runrace, Technogym, Forlì, Italy) to assess their anaerobic threshold (AT) and maximal oxygen uptake (V˙O2max). The test consisted of linear increases of running velocity of 1 km·h−1 every minute, starting at 8 km·h−1, until exhaustion, which was considered as the exercise level at which the subject was unable to maintain the running speed, i.e., muscular fatigue.

The treadmill slope was set at 1% to compensate for the lack of air friction (Jones and Doust 1996). Achievement of V˙O2max was considered as the attainment of at least 2 of the following criteria: (i) a plateau in oxygen uptake (V˙O2) despite increasing speed (<80 mL·min−1); (ii) respiratory exchange ratio (RER) above 1.10; and (iii) heart rate (HR) ± 10 beats·min−1 of predicted maximum HR was calculated as 220 – age (Howley et al. 1995). During the preliminary test, AT was determined using the V-slope method, which detects AT by using computerized regression analysis of the V˙O2 slopes vs. the carbon dioxide production (V˙CO2) plot during exercise (Beaver et al. 1986), while V˙O2max was calculated as the average V˙O2 during the final 30 s of the exercise test.

Fencing simulation test On a different day to the preliminary test, with an interval of at least 3 days, all subjects underwent a simulated fencing match on a standard fencing platform. Following a 15-min warm-up each individual then rested on a bench until cardiorespiratory variables returned to their pre-exercise levels. Recovery was considered complete when HR was below 10 beats·min−1 compared with the pre-exercise level and when RER was less than 0.9. The last

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3 min of seated rest were used to collect values of variables at rest and following this period the simulated match was started.

The simulation consisted of 3 bouts, each lasting 3 min and followed by 1 min of recovery, during which the subject sat on a bench. A further 3 min of recovery was allowed at the end of the simulation. Hence, the whole simulation test lasted a total of 18 min: 3 min of rest before beginning the match, 3 bouts each lasting 3 min spaced by 3 min of recovery (for a total of 12 min), and 3 min of final recovery. All experiments were conducted between 0900 and 1400 h. Subjects consumed a light meal at least 2 h (interval 2–5 h) before exercising. Meal consisted of a typical Italian breakfast with toasted bread, biscuits, fruit jam, honey, and milk. Subjects could eat ab libitum. Subjects were also asked to avoid caffeine and alcohol the day before tests were scheduled.

Variables Assessment of respiratory variables and HR V˙O2, V˙CO2, pulmonary ventilation (V˙E), and HR values were obtained throughout the preliminary and simulation tests by means of a portable metabolic system (MedGraphics VO2000, St. Paul, Minn., USA), which provides a 3-breath average of variables through telemetric transmission. This system has been shown to be reliable and to have positive agreement compared with a standard metabolic cart for laboratory use (Byard and Dengel 2002; Olson et al. 2003). The device weighs about 1.2 kg and includes the metabolic unit, battery pack, harness, chest belt for HR monitoring, face mask, and breathing valve. It is worn on the subject’s chest with a harness, without limiting the athlete’s movements.

Prior to testing, the VO2000 was calibrated according to manufacturer’s instructions. During the simulation test, the face mask for gas analysis was placed over the nose and mouth and the fencing mask was then fitted over the face mask.

Measurement of aerobic energy expenditure and anaerobic glycolysis During the simulation test aerobic energy expenditure (EE, expressed as kcal·min−1) was calculated by utilizing the Weir equation (Weir 1949; Mansell and Macdonald 1990): EE ⫽ 3.941 × V˙O2 ⫹ 1.106 × V˙CO2 This equation was used when the RER was <1, while an oxygen caloric equivalent of 5.04 was used when EE became >1. In this case it was assumed that all aerobic energy was derived from carbohydrate oxidation.

Blood samples were obtained with a finger prick and blood lactate (BLa) concentration was measured at rest, at the end of each round and at the third and fifth minutes of the final recovery by using a portable lactate analyzer (Lactate Pro, Arkray Inc., Kyoto, Japan), to evaluate the time course of lactate concentration.

Statistical analysis Data were averaged over 3 min during the rest period before the simulation bout, during rounds, and during postsimulation recovery, while a 1-min average was employed for the recovery periods between rounds. In this manner, information on the time course of studied variables was gathered and differences among the various protocol periods were detected. Responses are reported as means ± SD. Comparisons between periods were performed using repeated measures ANOVA, followed by Neuman–Keuls post hoc test when appropriate. Significance was set at a P value of <0.05. Descriptive statistics were performed on each variable before ANOVA to confirm the assumptions of normality by means of the Kolmogorov–Smirnov test. The ␣ level was set at P < 0.05.

Statistics were calculated employing commercially available software (Graph-Pad Prism).

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Table 1. Mean group values ± SD of maximum oxygen uptake (V˙O2max; expressed as absolute and indexed by body mass values), maximum heart rate (HRmax), oxygen uptake at anaerobic threshold (V˙O2AT), and heart rate at anaerobic threshold (HRAT) reached by subjects during the preliminary incremental test.

Mean SD

V˙O2max (mL·min·kg−1)

V˙O2max (mL·min−1)

HRmax (beats·min−1)

V˙O2AT (mL·min−1·kg−1)

V˙O2AT (mL·min−1)

HRAT (beats·min−1)

46.3 5.2

3168.6 558.4

194.5 9.6

37.9 5.5

2498.5 424.9

173.3 9.2

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Results All subjects completed the study protocol. Table 1 shows the results of the incremental preliminary test. Figures 1 to 3 depict results of the ANOVA test applied to the mean value of variables during the various protocol periods. HR (Fig. 1A) increased during the fencing bouts in comparison with rest. This HR elevation was present during the whole test, including the recovery phases between bouts and the 3 min of final recovery after the test. HR was below the AT level previously assessed during the preliminary incremental test for the entire period of the simulation, with the exception of the last bout. HR progressively increased throughout the whole combat, as testified by the fact that this parameter was higher during fight 3 in comparison with fight 1. V˙O2 (Fig. 1B) rose during the combat as compared with rest, without significant differences between rounds and recoveries, with the exception of the final recovery, when V˙O2 decreased towards resting level. V˙O2 always remained below the AT level.

Very similar behaviour was observed between V˙CO2 and V˙E (Fig. 2A and 2B), since they both increased throughout the test to return towards baseline during the final period of recovery. As reported for HR and V˙O2, both V˙CO2 and V˙E remained below AT values throughout the combat simulation.

Finally, Fig. 3A shows EE time course, which obviously resembled that of V˙O2. It is noteworthy that during the whole test EE averaged 10.24 ± 0.65 kcal·min−1, i.e., 8.6 ± 0.54 METs. Figure 3B depicts BLa behaviour. This variable was seen to increase abruptly even during the first round to maintain a stable level throughout the test. BLa reached its maximum during the final recovery minute between rounds, when it reached a value of 6.9 ± 2.1 mmol·L−1.

Fig. 1. Group heart rate (HR) values (A) and oxygen uptake (V˙O2; B) during the various periods of the fencing match. The level of anaerobic threshold is identified by a horizontal line. Values are means ± SD (n = 15). *, p < 0.05 vs. rest; †, p < 0.05 vs. final recovery; ‡, p < 0.05 vs. recovery 1; §, p < 0.05 vs. recovery 2; ¶, p < 0.05 vs. fight 1.

Discussion This investigation aimed to study energetic demand during a fencing competition. From the present data it appears that aerobic energy source is only moderately recruited during fencing.

Indeed, during the fight, V˙O2 and HR remained below the AT level previously assessed during the preliminary incremental test, with the exception of HR during the last fight bout, when this parameter was slightly increased with respect to AT. Very similar behaviour was also observed for V˙E and V˙CO2, thus confirming that fencing imposed moderate respiratory and metabolic stress only.

To the best of our knowledge this is the first study to assess energy requirements during fencing. Thus, the present information could be useful for coaches to devise specific training programs able to develop the specific adaptations required by fencing. Notwithstanding the fact that aerobic energy source appeared to be only moderately recruited and that athletes performed below the level of AT, it is noteworthy that the energy expenditure seemed to be high, since EE was on average about 10 kcal·min−1 (i.e., 600 kcal·h−1) during combat. This phenomenon can be explained by taking into consideration that the mean AT level of the fencers enrolled in the present investigation was high in relation to V˙O2max, as it was on average about 78% of V˙O2max.

Hence, even though athletes performed below the AT level, it should be considered that their EE was high in absolute terms.

This elevated AT in relation to V˙O2max bore witness to the concept that our group was constituted by well-trained athletes. It is to be noted that this energy expenditure very likely underestimated the

real energy requirement since it did not take into account the energy derived from the anaerobic metabolism.

Concerning BLa measures, it seems that the lactic anaerobic capacity was moderately activated to support the energy requirements of combat. Indeed, this parameter remained above 6 mmol·L−1 throughout the combat simulation, with a peak of 6.9 mmol·L−1 during the final recovery. This occurrence appears to be at odds with the finding that athletes performed below the level of AT. This outcome can probably be ascribed to the fact that, during combat, athletes used the arm muscles to a higher level of recruitment than during the incremental test employed to assess AT. It is well known that arms have a greater composition in fast-twitch fibers than legs and that these kinds of fibers produce a greater quantity of lactate than the slow-twitch ones (Saltin and Gollnick 1983). Therefore, it is reasonable to predict a greater BLa accumulation when athletes use arms as compared with legs.

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Fig. 2. Group carbon dioxide production (V˙CO2) values (A) and pulmonary ventilation (V˙E; B) during the various periods of the fencing match. The level of anaerobic threshold (AT) is identified by a horizontal line. Values are means ± SD (n = 15). *, p < 0.05 vs. rest; †, p < 0.05 vs. final recovery.

Thus, despite the fact that fencers performed below the AT level previously determined during a running test, the relatively high BLa value during the exercise bouts can be explained by taking into consideration that during the simulated fighting, it is likely their arm muscles were more engaged. It is of interest that HR showed a progressive increase throughout the whole combat, as testified by the fact that this parameter was higher during fights 2 and 3 in comparison with fight 1. This phenomenon was not evident for the other gathered metabolic variables. This occurrence suggests that there was a sort of dissociation between HR and the metabolic requirements of the exercise being performed, which caused an increase in HR over the real metabolic engagement.

Very similar HR behaviour was described in research reporting that when the exercise is characterized by alternate phases of maximal exercise and recovery, then HR provides overestimated values of energy expenditure (Crisafulli et al. 2006a, 2009). In fact, both maximal and supramaximal bouts of exercise impact profoundly on cardiovascular homeostasis since they modify cardiac pre-load, after-load, and contractility, which stress the cardiovascular regulatory systems and induce compensatory tachycardia (Crisafulli et al. 2004, 2006b). Hence, the present report further strengthens the concept that the use of HR monitoring to assess the intensity of exercise may be unreliable in activities that involve repeated bouts of maximal and supramaximal exercise and lead to a massive recruitment of anaerobic glycolysis.

Another finding deserving attention is that none of the studied variables returned to rest level during the 3 min of final recovery.

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Fig. 3. Group energy expenditure (EE) values (A) and blood lactate (BLa; B) during the various periods of the fencing match. The level of anaerobic threshold (AT) is identified by a horizontal line. Values are means ± SD (n = 15). *, p < 0.05 vs. rest; †, p < 0.05 vs. final recovery.

This suggests that a 3-min recovery was insufficient to completely recover from the strain that was due to exercise. In conclusion, the data from our study suggest that fencing is a moderately physically demanding activity for skilled fencers, such as those studied in the present investigation. Both the aerobic energy metabolism and anaerobic lactic energy sources are moderately recruited.

Thus, present data support the concept that successful fencing performance depends more on skill and technique than the superior aerobic and anaerobic capacities. Further study is needed to better clarify this point. Moreover, HR can be misleading when estimating energy expenditure in this kind of competition since this parameter showed a progressive increase that was dissociated to oxygen uptake during combat. Finally, interval periods between rounds do not allow for complete recovery. Given the incomplete recovery between bouts, it is important that athletes develop specific training programs able to improve this ability. All these facts should be considered by coaches when preparing training programs for athletes. Since the scientific literature on fencing is not particularly abundant, future research is needed to better characterize this sport from a physiological point of view.

Acknowledgements This study was supported by the University of Cagliari, the Italian Ministry of Scientific Research, and the Regional School of Sport of Sardinia, Italian Olympic Committee (Italy). The authors wish to thank Mr. Barry Mark Wheaton for his editorial assistance.

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References Beaver, W.L., Wasserman, K., and Whipp, B.J. 1986. A new method for detecting anaerobic threshold by gas exchange. J. Appl. Physiol. 60(6): 2020–2027.

PMID:3087938.

Byard, A.D., and Dengel, D.R. 2002. Validity of a portable metabolic measurement system. Med. Sci. Sports Exerc. 34(5): S149. doi:10.1097/00005768200205001-00829.

Crisafulli, A., Carta, C., Melis, F., Tocco, F., Frongia, F., Santoboni, U.M., et al.

2004. Hemodynamic responses following intermittent supramaximal exercise in athletes. Exp. Physiol. 89(6): 665–674. doi:10.1113/expphysiol.2004.

027946. PMID:15328308.

Crisafulli, A., Pittau, G.L., Lorrai, L., Cominu, M., Tocco, F., Melis, F., et al. 2006a.

Poor reliability of heart rate monitoring to assess oxygen consumption during field training. Int. J. Sports Med. 27(1): 55–59. doi:10.1055/s-2005-837504.

PMID:16388443.

Crisafulli, A., Tocco, F., Pittau, G., Lorrai, L., Porru, C., Salis, E., et al. 2006b. Effect of differences in post-exercise lactate accumulation in athletes’ hemodynamics. Appl. Physiol. Nutr. Metab. 31(4): 423–431. doi:10.1139/h06-017. PMID: 16900232.

Crisafulli, A., Vitelli, S., Cappai, I., Milia, R., Tocco, F., Melis, F., et al. 2009.

Physiological responses and energy cost during a simulation of a Muay Thai boxing match. Appl. Physiol. Nutr. Metab. 34(2): 143–150. doi:10.1139/H09-002.

PMID:19370044.

Appl. Physiol. Nutr. Metab. Vol. 39, 2014

Howley, E.T., Bassett, D.R., and Welch, H.G. 1995. Criteria for maximal oxygen uptake: review and commentary. Med. Sci. Sports Exerc. 27(9): 1292–1301. doi:10.1249/00005768-199509000-00009. PMID:8531628.

Jones, A.M., and Doust, J.H. 1996. A 1% treadmill grade most accurately reflects the energetic cost of outdoor running. J. Sports Sci. 14: 321–327. doi:10.1080/ 026404196367796, 10.1080/02640419608727717. PMID:8887211.

Mansell, P.I., and Macdonald, I.A. 1990. Reappraisal of the Weir equation for calculation of metabolic rate. Am. J. Physiol. Regul. Integr. Comp. Physiol.

258(27): R1347–R1354. PMID:2360685.

Olson, T.P., Tracy, J.E., and Dengel, D.R. 2003. Validity of a low-flow pneumotach and portable metabolic system for measurement of basal metabolic rate.

Med. Sci. Sports Exerc. 35(5): S143. doi:10.1097/00005768-200305001-00795.

Roi, G.S., and Bianchedi, D. 2008. The science of fencing: implications for performance and injury prevention. Sports Med 38(6): 465–481. doi:10.2165/ 00007256-200838060-00003. PMID:18489194.

Roi, G.S., and Pittaluga, I. 1997. Time-motion analysis in women’s sword fencing. In Proceedings of the 4th IOC Congress on Sport Sciences. Oct. 22–25; Monaco: 66.

Saltin, B., and Gollnick, P.D. 1983. Skeletal muscle adaptability: significance for metabolism and performance. In Handbook of Physiology, Section 10, Skeletal Muscle, Chapter 19. Edited by L.D. Peachy. American Physiological Society Bethesda, Md., USA. pp. 555–631.

Weir, J.B. 1949. New methods for calculating metabolic rate with special reference to protein metabolism. J. Physiol. 109: 1–9. PMID:15394301.

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