Techniques May 2019

Contents Volume 12 Number 34 / May 2019

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in every issue

FEATURES

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A Letter From the President USTFCCCA Presidents

AWARDS

54 2019 National Indoor

Track & Field Athletes and

Coaches of the Year

Speed Play

Guiding skill through a seamlessly sequenced sprint curriculum.

Brad H. DeWeese EdD, John P. Wagle PhD, Joel Williams, and Matt L Sams PhD

30 The Bent Twig Effect

A Trajectory for Growth and Development

Matthew Buns, Ph.D.

38 Selected Segment

Dynamics in Javelin Throwing

Andreas V. Maheras, Ph.D.

56 Spring Maintenance of Track & Field Facilities

By Mary Helen Spreche

on the COVER: former LSU standout aleia hobbs Photograph by Kirby Lee Image of Sport photo

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A LETTER FROM THE PRESIDENT

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e’re already into May! That means that we are either into the championship part of our season or right on the cusp of it.

This is the time of year when really begin to see the fruits of our labor. The countless hours of practice and meets over the past few months should be manifesting themselves in the form of seasonal best performances.

This is also the time of year that we begin to realize these are the final weeks for some of the student athletes to be members of your team. Hopefully you can look back on the time that you’ve had with them with great pride and fulfillment, knowing that you’ve given them your best effort. That effort includes much more than simply writing their workouts and developing race plans for them. As coaches, we are given a unique opportunity to have a very significant impact on not only the athletic careers of our student athletes, but also on their development as young adults. We’ve guided them through the trials and tribulations of being a freshman, possibly being away from home on their own for the first time in their lives. We’ve taught them how to manage the demands on their time created by their coursework, training, travel and social life. In short, we’ve helped them grow into responsible individuals that will go on to productive and fulfilling lives outside of the world of track & field. I think it’s not out of line for us to give ourselves a pat on the back — we’ve earned it.

Once the 2019 Outdoor Track & Field season is over, I hope that each of you takes the time to do something for yourselves. As we all know, the “off season” is far shorter than we’d like it to be, and we will all be back at the grind before we know it. One thing that you might want to consider doing for yourself is attending a Track & Field Academy program this summer. The Specialist Certification Courses are being offered at Towson University in Maryland on July 16 – 20.

Slots are available in Sprints, Jumps, Throws, Endurance and Combined Events.

In addition, there are a few offerings of the Strength & Conditioning Coach Certification course being offered at various locations around the country.

Check the Track & Field Academy section of the USTFCCCA website for dates and details. Finally, it’s not too early to start thinking about attending the 2019 USTFCCCA Convention in Orlando. The convention will be held on December 16 – 19 at the JW Marriott Grand Lakes Resort. There will also be a number of Track & Field Academy programs held on the front and back ends of the convention.

Best of luck to everyone through the rest of this season, and don’t forget that pat on the back !

Publisher Sam Seemes Executive Editor Mike Corn DIRECTOR OF MEDIA, BROADCASTING AND ANALYTICS Tom Lewis Membership Services Kristina Taylor communications Tyler Mayforth, Matthew Schaefer Photographer Kirby Lee editorial Board Tommy Badon, Todd Lane, Boo Schexnayder, Derek Yush ART DIRECTOR Tiffani Reding Amedeo

Published by Renaissance Publishing LLC 110 Veterans Memorial Blvd., Suite 123, Metairie, LA 70005 (504) 828-1380 myneworleans.com

USTFCCCA National Office 1100 Poydras Street, Suite 1750 New Orleans, LA 70163 Phone: 504-599-8900 Fax: 504-599-8909 Website: ustfccca.org

DENNIS SHAVER President, USTFCCCA Dennis Shaver is the head men’s and women’s track and field coach at Louisiana State University. Dennis can be reached at shaver@lsu.edu

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Techniques (ISSN 1939-3849) is published quarterly in February, May, August and November by the U.S. Track & Field and Cross Country Coaches Association.

Copyright 2019. All rights reserved. No part of this publication may be reproduced in any manner, in whole or in part, without the permission of the publisher. techniques is not responsible for unsolicited manuscripts, photos and artwork even if accompanied by a self-addressed stamped envelope. The opinions expressed in techniques are those of the authors and do not necessarily reflect the view of the magazines’ managers or owners. Periodical Postage Paid at New Orleans La and Additional Entry Offices. POSTMASTER: Send address changes to: USTFCCCA, PO Box 55969, Metairie, LA 70055-5969. If you would like to advertise your business in techniques, please contact Mike Corn at (504) 599-8900 or mike@ustfccca.org.

DIVISION PRESIDENTs DIVISION I

Connie Price-Smith NCAA Division 1 Track & Field

vicki mitchell NCAA Division I Cross Country

Connie Price-Smith is the head men’s and women’s track and field coach at the University of Mississippi. Connie can be reached at cmprice@olemiss.edu

Vicki Mitchell is the director of track and field and cross country at the University of Buffalo. Vicki can be reached at vam2@buffalo.edu

Kevin LaSure NCAA Division II Track & Field

Jim Vahrenkamp NCAA Division II Cross Country

Kevin is the head track and field coach at Academy of Art University. Kevin can be reached at klasure@academyart.edu

Jim Vahrenkamp is the Director of cross country and track and field at Queens University. Jim can be reached at vahrenkampj@queens.edu

Kristen Morwick NCAA Division III Track & Field

Dustin Dimit NCAA Division III Cross Country

DIVISION II

DIVISION III

Kristen is the Head Women’s Track and Field and Cross Country coach at Tufts University and can be reached at kristen. morwick@tufts.edu

Dustin is the Head Men’s Track & Field and Cross Country coach at Rowan University and can be reached at dimit@rowan.edu

Mike McDowell NAIA Track & Field

Heike McNeil NAIA Cross Country

Mike McDowell is the head men’s and women’s track and field coach at Olivet Nazarene University. Mike can be reached at mmcdowel@olivet.edu

Heike McNeil is the head track and field and cross county coach at Northwest Christian University. Heike Can be reached at hmcneil@nwcu.edu

Ted Schmitz NJCAA Track & Field

Don Cox NJCAA Cross Country

Ted Schmitz is the head track and field coach at Cloud County Community College. Ted can be reached at tschmitz@cloud.edu

Don Cox is the head track and field and cross country coach at Cuyahoga Community College. Don can be reached at donald.cox@tri-c.edu

NAIA

njcaa

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Speed Play

Guiding skill through a seamlessly sequenced sprint curriculum.

Brad H. DeWeese EdD, John P. Wagle PhD, Joel Williams, and Matt L Sams PhD

kirby lee image of sport 8

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ithin track & field, various models exist regarding the macro-management of speed enhancement. For instance, coaches may subscribe to a short-to-long, long-to-short, or concurrent system to inform global progressions within the allocated preparation time. Though these themes speak to how a plan conceptually attempts to advance the skill of sprinting along with specific fitness, these overarching modes of training are superficial and limited in their scope as it relates to the micro-level management of planning.

Specifically, these broad models fail to provide insightful perspective that allows the coach to carefully deliver nuanced programming, and more importantly, instruct a speed development session with precision. In other words, having greater clarity on both the intended goals and actual outcomes of a given sprint tactic or drill may improve a coach’s ability to deliver targeted cues or verbal instruction. As a result, the motor-learning effects of properly designed sprint-skill development sessions are augmented through informed and artful coaching. While the development and practice of coaching should be grounded in evidence, they are often separated — causing a detrimental dissociation between the aspects of curriculum delivery, skill analysis, and movement modification. Therefore, the purpose of this article is to arm coaches with a logical progression of tactics that develops sprint skill while considering the temporal aspects of high-velocity running.

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SPEED PLAY Advances in Sprint Modeling The current understanding of maximum effort locomotion demonstrates that sprinting is indeed a skill. While elegant in design, Bushnell and Hunter’s (2007) investigation on the relationship between movement quality and running speed demonstrated that while endurance athletes and sprinters shared similar biomechanical and spatiotemporal qualities at low cadences, the distance runners within their study failed to adjust technique as speed increased.

In short, this supports the notion that sprinting proficiency is improved through coaching intervention and quality-repetition.

As a skill, sprinting may be further enhanced through training tactics that mature the musculoskeletal system’s ability to efficiently produce, tolerate, and transfer high forces into the track (Colyer et al., 2018). Moreover, those forces should be distributed in an appropriate magnitude and direction so as to maintain elastic qualities while minimizing braking (Nagahara et al., 2019).

Lastly, the properly-oriented forces must be transmitted within an abbreviated amount of time, typically ~90-100ms at top speed, which reinforces explosive strength as the primary criterion for sprint success.

This explosivity is underpinned by a collection of neuromuscular factors including, but not limited to motorunit typing, intra- and inter-muscular coordination, rate-coding, and neural drive, which collectively work to actualize sprint-movement characteristics.

Because of their role in rate and magnitude of force development, these neuromuscular factors serve as prerequisites for proper mechanical actions within critical time frames. For example, sprinters who initiate GC with as stance phase that is more proximal to the center of mass at top-speed are more likely to conserve energy and prioritize elastic behavior through the SSC, a rapid and forceful lengthening of a muscle-tendon complex followed by an immediate shortening or contraction (Komi, 2008).

Practically speaking, Manzer, Mattes, and Hollander (2016) described this phenomenon with the following observation of top-speed sprinting: “a high lifted knee stretches the hamstrings and gluteal muscles for the forthcoming hip 10

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extension at downswing during the presupport-phase. This leads, furthermore, to a sudden stop of the upper leg at maximum knee lift to the momentum transfer on the entire body and supports the takeoff extension because the time of maximum knee lift coincides with the takeoff of the opposite side.”

Conceptually, the SSC is important for sprinting as it underpins the spring-mass model (SMM). The SMM depicts sprinting as the result of a body mass bouncing along two springs (Blickhan, 1989, Dalleau et al., 1998, Dutton & Smith, 2002, Farley & Gonzalez, 1996). During a complete running cycle, one spring compresses and propels the sprinter’s body forward. Simultaneously, the other spring swings forward in preparation for ground contact. Within an upright sprint, compression of the spring begins at foot strike, which results in horizontal braking forces. This sudden deceleration assists in propelling the swing leg forward in preparation for the following step. As the center of mass moves ahead of the stance foot, the sprinter enters the “mid-stance” phase. Within the SMM, the spring is compressed to the lowest point, which coincides with a lowered center of mass at mid-stance. The most proficient sprinters are able to minimize this downward COM displacement – once again pointing to the importance of magnitude and rate of force production in sprinting (Mann & Murphy 2015).

Finally, the push-off (toe-off) segment of the stance phase describes the return of energy through the extension of the coiled spring. This return of force projects the sprinter forward into the next step (DeWeese, 2015).

Though useful in rudimentary conceptualization, the SMM is limited in its appreciation of integral aspects of running mechanics such as the unique force-time characteristics of elite sprint foot-strikes. Specifically, Clark & Weyand (2014) demonstrated that fast sprinters produce a significant amount of their ground force within the first third to half of a stance phase. Furthermore, this same research group helped decode this asymmetrical force profile through a Two-Mass Model (TMM) system (Clark et al., 2017). Still mathematically elegant, the TMM only requires the mass of a sprinter’s shank and remaining body, alongside variables collected during a

sprint cycle: contact time, aerial time, and shank acceleration.

This revised TMM system considers two consistent and consecutive running actions that are independent of movement speed. In short, ground contact results in a nearly-immediate halt of the shank while the remaining body accelerates up and ahead of the shank throughout stance phase. We can represent these events mathematically as two overlapping impulses: Impulse 1 (I1) captures the ground reaction forces and temporal characteristics of shank stabilization, while Impulse 2 (I2) describes the forces required to accelerate the rest of the body through a given stance phase (Clark et al., 2017).

Acknowledging the depth of value that a TMM adds to the assessment of individualized sprinter profiling and programming, the authors developed and validated a method to capture ground reaction force data using inertial measurement units (IMU) within a traditional training environment. As compared to recent investigations that capture kinetic data during open sprints on an instrumented track (force plates), this is the first time that sprint waveforms have been collected and analyzed in a manner that is unrestrained from the laboratory setting.

What is Impulse and Why is it Important?

Force transmission to the track does not occur instantaneously. Instead, a sprinter imparts force to the track across the entire stance duration, which ranges from 100-130ms during acceleration to 85-90ms during maximum velocity sprinting (Aagaard et al., 2002). Impulse is the product of these ground reaction forces and the stance duration for each step. While large ground reaction forces are integral to successful sprint performance, the time-dependent nature of sprinting prevents athletes from fully expressing their maximum force capabilities (Cormie et al., 2010; Seitz et al., 2014). Therefore, rate of force development (RFD) is integral in allowing athletes to develop high percentages of their maximum force capabilities during each step permitting large impulses to be produced under the time constraints of sprinting.

Because it is the product of force and

SPEED PLAY

Figure 1: The staging and exit of a Crouch Start.

Figure 2: Force-Waveform representations of the Two-Mass Model for steps 1,3,7,9,11 for the Crouch Start.

time, impulse describes the area under the force-time curve. In theory, practitioners can describe the shape and magnitude of an athlete’s sprint force-time profile similarly to phase analyses performed on the countermovement jump (Mizuguchi et al., 2015; Sole et al., 2018). The recent development of the TMM (Clark et al., 2017) provides a platform from which to examine the qualitative and quantitative characteristics of an athlete’s running form at ground contact. Specifically, a coach can tie the movement quality observed on the track to the impulse profile of each stance phase. Further, supplemental information regarding common impulse shapes for various sprint tactics can aid coaches in properly sequencing these drills in a logical, timely manner.

Speed Play Using force-time waveform models collected over the training season of two highlevel male sprint athletes (a 2018 Olympic sprint-sport athlete who is also a former Division 1 All-American sprinter and an International sprinter with personal bests of 10.11 and 20.23 in the 100m and 200m, respectively) as a guide, we hope to provide the coaching community with greater clarity on several sprint drills common to track & field. While not an exhaustive 12

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list, the sprint drills presented within this paper were strategically chosen for their ability to emphasize certain aspects of a sprint run, while collectively exposing the athlete to a wide array of movement velocities and force characteristics.

This data and the accompanying interpretation may help with the organizational process of training tactics within a competitive year. As Coyler and associates (2018) remind us, an athlete’s response to training is highly specific to the conditional stimuli (e.g., velocity and load) prescribed. These conditions should be programmed in an emphasis/de-emphasis manner throughout the training year as improvements during one phase may be accompanied by reductions in performance across another (Coyler et al., 2018).

Due to the acknowledgement of these interconnected force signatures, it may be possible to better represent the phasic nature of sprinting and provide targeted constraints by which motor learning can be maximized. More specifically, the consideration of both the absolute and relative magnitudes of the ‘two-masses’ make it more reasonable to infer potentially distinct characteristics. This may then lead to more precise methods that can be applied in the development of sprint skill. While limited by population, the data gleaned

from this ecologically-valid investigation demonstrates, for the first time, what occurs when traditional sprinting is altered to enhance or address isolated aspects of a run.

Acceleration Tactics Within a periodized program, coaches may elect to enhance race performance through concentrated (not isolated) efforts of shorter-distance sprints prior to higher workloads at top-speed. This training decision is supported by Naito et al.

(2013) and Schiffer (2009) who concur that maximum velocity results from the acceleration established within earlier zones of a sprint race. Therefore, if this premise is to be accepted, then it is logical to equip the coach with a diverse array of tactics by which to systematically mature the foundational component of skillful sprinting.

Further, if we acknowledge that sprinting is a skill that depends on neuromuscular readiness, coaches should emphasize programming strategies that improve movement proficiency through organized training tactics that consider both technical aspects and biomechanical characteristics.

Standing Starts Crouch Start: The track and field block start is considered to be a high-skill, high-out-

Figure 3: Starting position and exit steps of the Prone Start.

Figure 4: Force-Waveform representations of the Two-Mass Model for steps 1,3,7,9,11 for the Prone Start.

put event that may require rehearsal under near-optimal conditions of readiness (Bezodis et al., 2018; Brazil et al., 2018). As such, a less technical yet consistent starting-stance for multiple sprint efforts within a training session is warranted.

From a staggered stance that is approximately two foot lengths apart, the crouch start (CS) places the athlete’s center of mass approximate to that of a block start.

Specifically, the athlete will descend their hips down into a “loaded” position while maintaining a long and braced torso. Once the squatting position has been established, the sprinter should take a deep inhalation while raising their front forearm/hand to their forehead while the back hand is taken to the hip. Just before driving out, the athlete may choose to “fall” into the start by slightly flexing/ dropping the lead knee so as to promote a more horizontal displacement during exit through the creation of a more positive shin angle.

While Shinohara et al. (2018) discovered that the CS slightly differs from the block start with regard to spatiotemporal parameters within both early and later stages of acceleration, it may allow the sprinter to better orient force application into a more horizontal direction over the entire acceleration phase. Its kinematic similarities do, however, provide the athlete with as

advantaged of a starting position as possible without the use of additional equipment. This gives the CS high practical utility in training sprinting athletes both on the track and in other sports. All considered, a full sprint from the CS will serve as the criterion for comparing the subsequent acceleratory tactics within this article.

Reactive Accelerations Prone Start: As seen in Figure 3, the Prone Start is a training tool that places the athlete at the lowest possible point on the track. From a position that is approximate to the bottom of a push-up, the sprinter responds to an external cue (often a clap), pushing their center of mass up and out.

This explosive start should be done while attempting to maintain a long and braced torso in order to counter the initial step’s knee drive “toward the chest.” Lastly, in order to prevent over-rotation and/or a premature vertical lift of the torso, the sprinter should emphasize aggressive and rapid foot strikes that coincide with “long and strong” arm cycles.

Considering the force-time wave forms, this training tactic appears to increase the total time to peak force in order to raise the body from an exaggerated starting position. As such, this drill led to a larger total impulse through the first 3 steps

with a larger emphasis toward I1 in order to rapidly stabilize the up-and-ahead movement of the COM. Furthermore, the dataset used for this analysis demonstrates lower peak forces through most of the 12 steps, which could result from the more horizontally-oriented hip extension.

Taken together, this drill should be considered an advanced tactic as the sprinter must be strong enough to generate enough propulsion during I1 in order to displace horizontally, while still being able to ‘hold themselves up’ against the lowered COM. The alteration in force production demands relative to the CS through a kinematic constraint (i.e. exaggerated horizontal orientation) make the prone start a sprint tactic that allows the athlete to emphasize proper direction of force application. In addition, the prone start can be used to stage more traditional starts so as to potentiate subsequent efforts or to retain previously developed acceleration skills, which includes the sensation of aggressive pushing “down and back” (i.e. properly oriented force production).

Chest Pass to Chase: The Chest Pass Chase is a medicine ball starting drill that can assist the sprinter in experiencing and developing a piston-like action against the track. The athlete will begin this sprint by placing themselves in a CS with a medimay 2019 techniques

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SPEED PLAY

Figure 5: The set-up, medicine ball release, and exit of the Chest Pass Chase.

Figure 6: Force-Waveform representations of the Two-Mass Model for steps 1,3,7,9,11 for the Chest Pass Chase.

Figure 7: The coach-supported starting position, release, and exit of the Falling Start.

Figure 8: Force-Waveform representations of the Two-Mass Model for steps 1,3,7,9,11 for the Falling Start.

Figure 10: Force-Waveform representations of the Two-Mass Model for steps 1,3,7,9,11 for the Incline Sprint.

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cine ball held at chest height, being stabilized by elbows “tucked” into the sides. After an initial fall with the aim of placing the “hips ahead of the heels”, the runner will push and project their center of mass out in a manner to transfer momentum into the ball.

Furthermore, the medicine ball’s path dually serves as an external cue of both magnitude and direction of force application, with a linear toss being desired.

As noted in Figure 6, the chest pass chase appears to primarily influence the initial acceleration of a sprint run, likely as a result of an increase in ground contact time needed to stabilize oneself from the pronounced COM displacement. Specifically, there is an increase in the total time to peak force and a greater reliance on I2 during steps 1 through 3. Interestingly, the sprinter returns to nearbaseline numbers once the traditional sprint form is regained. This tactic allows the athlete to emphasize and rehearse proper initiation of early acceleration initially while seamlessly progressing to open sprinting. Considering the information above, the chest pass chase could be a logical precursor to potentiate block starts where horizontal displacement and larger force production is desired. This versatile tool may be leveraged by coaches frequently in a long-term sprint skill development plan due to its versatility.

Falling Start: The Falling Start is yet another reactive drill that conceptually requires the runner to become comfortable with being “ahead of themselves” (i.e. horizontallyoriented). As the sprinter falls away from the coach’s grasp, the emphasis should be on leading into the lean through the hips rather than the upper body. This is done to prevent

a breaking of the waist that could limit terminal hip flexion which stages the first step.

After falling “long and tall”, the athlete should be cued to punch the ground hard and fast during the initial steps in order prevent over-rotation or the desire to “pop-up” during transition.

Considering the force waveform data, the falling start leads to increased stance times within the initial steps 1-3 coupled with a larger reliance on I2, perhaps resulting from the significant horizontal orientation of hip extension on exit in a somewhat similar manner to the prone start.

However, explosive strength rises through step 9 likely as a combined result of optimal positioning and a taller COM compared to a traditional crouch or prone start.

Combined, these findings suggest that the falling start may be a suitable drill to be performed prior to accelerativetransition work or top-speed training as it compliments and reinforces late-stage skill.

Resisted Sprinting Incline Sprints: One form of increasing resistance to traditional sprinting is through altering environmental constraints. Theoretically, incline sprinting is thought to “bring the ground to the athlete” who may have difficulty managing and/or executing proper acceleratory mechanics.

Specifically, the steady climb and rise of the ground permits a runner continuous opportunity to rehearse limb-actions and foot strikes that are propulsive in nature. While limited by subjects, Bingham and colleagues (2015) demonstrated that incline sprinting on a 5-degree slope created spatiotemporal characteristics that were similar to the first 5 steps from block exit on a flat track.

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SPEED PLAY

Figure 9: The starting stance, “falling ahead into a forward lean� strategy, and exit steps of the sled pull.

Figure 11: Force-Waveform representations of the Two-Mass Model for steps 1,3,7,9,11 for the Sled Pull.

Figure 12: Spatiotemporal characteristics of speed zones within a 100m dash.

that a sustained reliance on I2 is required for the production of propulsive forces against a rising slope. While I1 continues to drive an asymmetrical wave-form through ankle stabilization, net impulse is shaped by the work to drive the athlete up and ahead of each stance phase. As such, it appears that increasing the inclination of the running surface is a suitable method to enhance accelerative ability early during the preparation period and could be a viable option for the retention of early-phase sprint qualities during competitive or more specific periods of the training year.

Sled Towing: Arguably the most popular, and perhaps the most-researched, resist16

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ed-sprint tactic is the sled pull (Alcaraz 2018, Bachero-Mena & Gonzalez-Badillo, 2014, Bentley et al., 2014, Harrison & Bourke, 2009, Morin et al., 2016). Sled pulls follow a similar logic to incline sprinting, aiming to alter the environmental constraints in order to emphasize certain aspects of acceleration skill. Fluctuating the external resistance can modulate (both increase and decrease) the demand of horizontally-oriented force application during each ground contact. Theoretically, this drill serves to aid in the staging of proper segment alignment while also facilitating greater ground forces when chronically applied to acceleration-based training.

As a result of the external resistance, sled pulls have more programming considerations than other sprint-skill development tactics — particularly optimal load selection. While this continues to be a point of dialogue and debate within the coaching and scientific communities, the authors do not feel it is within the scope of this article to spend considerable time on this topic. However, it is worth noting that the authors feel that is most appropriate to rely on sled loads that are towards the modestend of external resistance, especially within a more mature or established track & field team environment. Briefly, conservative loading allows 1) more similar step

SPEED PLAY

Figure 13: The transitional mechanics of late-acceleration sprinting. Note the vertical shin coupled with a near-erect torso. The torso should continue to rise gradually over the next several steps to a point the joints are “stacked” entering maximum velocity.

Figure 14: Force waveform representations of the Two-Mass Model for the last several steps of the “Acceleration” zone compared to the first several steps of the “Hold” zone.

kinematics to unresisted sprinting, 2) more similar segment kinematics to unresisted sprinting, 3) better fatigue management, and 4) maintenance of elastic-reflexive mechanisms found in unresisted sprinting.

Furthermore, it is the authors’ contention that similar programming considerations should be made in sled pulls as in resistance training (e.g. loading variation) to create an environment that exploits physiological phenomenon (e.g. post-activation potentiation) and exposes the athlete to a broader spectrum of output demands.

The thoughtful manipulation of loading likely allows the athlete to both physically develop specific physical aspects relevant to sprinting as well as promote a more robust learning environment from a motor skill standpoint.

Programming nuances aside, sled pulls have considerable evidence supporting their use in improving sprint ability in distances less than 20m and coaches are warranted in frequently leveraging 18

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this tool (Alcaraz 2018). Considering the figure below, a moderately-loaded (~55% BW) sled pull led to an overall increase in ground contact time while producing a decrease in total force. Though initially counterintuitive, this may have resulted from a more horizontal orientation of the COM relative to the ground, where the athlete used the sled as an off-set in order to support a greater propulsive position.

In addition, total impulse increases 7-12% for steps 1-10, largely from an increase in I2, theoretically through an overload of the skill of transitioning through stance phase.

With this new information, it may be advantageous for the coach to emphasize that the athlete drives their hips ‘through’ the belt or apparatus that is tethering them to the sled during the pull.

Short Speed - Transitory Acceleration Hold: While Bezodis et al.

(2012) and others suggest movement behavior is slightly nuanced and “self-

selected” even at the elite level of competition, multiple sources have demonstrated that a 100m dash can be broken down into definable zones based on kinetic and kinematic similarities (Mackala, 2007; Nagahara et al., 2014a; Manzer 2016). Specifically, these zones can be summarized as the Early-Acceleration, Mid-Acceleration, Late-Acceleration, and Maximum Velocity as noted in Figure 12 (Bellon, 2016).

Success within the aforementioned transition or “late acceleration” phase requires the athlete to stay patient and unhurried as the torso opens up and “sits on top” of the previously established vertical shin.

Unfortunately, less skillful sprinters rush through this phase in order to “pop up and run”, sacrificing the last few meters of acceleration in order to satisfy the sensation of moving fast. This impatience can blunt maximum velocity through the compromise of posture, which can appear “seated” if the athlete fails to thoroughly

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SPEED PLAY

Figure 15: The entering mechanics of a Fly-In sprint run, highlighted by a tall rigid torso that provides freedom for a fullyflexed thigh at the termination of swing phase. This stages a more proximal ground contact, preserving the SSC. In addition, attention should be paid to the neutral knees at mid-stance (when both thighs are “underneath the hips”.

Figure 16: Force waveform representations of the Two-Mass Model for the last several steps of the “Build” zone compared to the first several steps of the “Fly” (Maximum Velocity) zone.

drive themselves tall. And while a sprint should be seen as a fluid movement that is devoid of abrupt disruption, dividing the race into distinct stages may provide the coach with themes for the design of practice agendas. As such, the accelerationhold serves as a drill to (a) bridge between acceleration training and top speed, while (b) permitting the athlete time to maintain patience and drive toward pure upright mechanics.

Referring to the work of Mackala (2007), and Manzer (2016), this training unit attempts to provide the athlete with an opportunity to graduate through the initial and extended acceleration phases while being tasked with a controlled rise of the torso. Specifically, the coach will instruct the athlete to accelerate maximally from a crouch or block start up to a cone or landmark that is approximate to the onset of vertical shins. From here, the athlete can be cued to “maintain inertia or speed” by “not pushing on the gas pedal any further”. While “holding speed”, the sprinter should then allow the torso and head to “uncurl and rise in unison” as they “drive their hips up and through” to a top-speed “stacked” posture.

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In addition to the opportunity for a rehearsal of transitional mechanics, acceleration holds also serve as a bridge between programming tactics. For instance, this training tool can be used to regulate the exposure to higher velocities through the judicious placement of a hold cone. Practically speaking, a coach may place the cone at or before the vertical shin to limit intensity or move the cone ahead so as to introduce higher running speeds.

For example, Figure 14 visually represents the phase-to-phase characteristics of an acceleration hold where the sprinter’s vertical shin was identified to occur at approximately 35 meters. From here, the athlete was instructed to aggressively build speed from a crouch start up to a cone placed at the 35m mark, and then to “hold speed” while patiently unfolding the torso over the next several steps. Therefore, the last 6 steps of the “acceleration phase” are compared to the first 6 steps of the “hold phase”.

Data collected during this training session demonstrates that the overall ratio of I1 to I2 remains relatively unchanged as ground contacts hasten between the entry to and exit from “late-acceleration”,

which is bookmarked by the vertical shin and subsequent vertical torso. This may suggest that nuances for this drill then, are not necessarily in biomechanics, but in the art of coaching. Though the waveforms presented in Figure 14 may initially seem insignificant, they provide evidence that a properly executed hold produces similar kinetics as an open sprint, but at reduced velocities. This indicates that the acceleration hold fits best as a transitionary tool to longer sprints, but only if the athlete can demonstrate the necessary patience as they unfold at the hip during transition, which may be required in order to produce wave-form similarities. Future investigation should examine this drill using a diverse range of sprint abilities to determine if this is the manifestation of a learned effect of high-level sprinters, as was used in the current discussion.

Top Speed Tactics Fly-In: As described by coaching pioneers Seagrave (1996) and McFarlane (1993), the Fly-In drill is designed to isolate top-speed mechanics through the prescription of a pre-defined zone of no more than 4 seconds that is staged by a near or full build-

Figure 17: Force waveform representations of the Two-Mass Model comparing the last 5 of the first “Fly” (Build) zone, the middle 5 steps of the “Float” zone, and the first 5 steps of the final “Fly” (Reapply) zone.

Figure 18: Conceptual framework for the placement of sprint tactics within a training plan through the consideration of skill maturity and foot-toground force interplay.

up. Once at top-speed, the athlete should demonstrate a “stacked” posture alongside full and unhindered upper- and lowerbody limb cycles that permit a proactive and deliberate foot-strike “down and through” the track. This action attempts to maintain an optimal hip height through a more proximal touchdown, which serves to the maximize the SSC. Compared to acceleration or transitional sprint techniques, the fly-in is reliant on a sharp rise in I1. Recall that I1 relates to the time it takes to stabilize the shank upon ground contact. Thus, the faster an athlete can steady the shank at top speed, the more economical that stance may be.

This is demonstrated well in the figure below, with the athlete delivering a high relative contribution to the total impulse from I1 during these strides taken following an 40m build. The stronger and more skilled athletes will be able to provide a substantial magnitude and rate of force production, resulting in a more prominent I1. The overall strength of the leg musculature allows the athlete to aggressively initiate contact with the ground during stance phase, causing positive or neutral vertical hip displacement. This positive

or vertical hip displacement coupled with a foot-strike just ahead of the center of mass at permits ‘clean’ ground contact and facilitates very high force production under a time constraint of approximately 90-100ms. Thus, the force waveforms presented below not only serve to further elucidate the efficacy of this tactic; but may also be useful in evaluating the quality of ground contact. Because top-speed is the crowning component of a short-to-long progression, this could serve as a means of final evaluation of program efficacy prior to race modeling or competition.

The “Fly-Float-Fly” (FFF) also known as the “Sprint-Float-Sprint” is another top speed training tactic of which practitioners have long speculated is more advanced due to the increased time spent at maximum velocities. Specifically, the FFF evolves from the fly-in by exposing the sprinter to a pair of fly-zones separated by a “float” zone that is thought to permit a brief neurologic recovery. Similar to the fly-in, the top speed zones are brief (2-4 seconds), but combine to yield a larger sum of stimulus through the double peaks at maximum velocity running.

Furthermore, it has been postulated that

the second “fly” zone will result in the highest velocities due to the potentiating nature of the run if the sprinter “maintains inertia” during the float “recovery” zone.

Historically, this effect has been noted through the capture of average velocity over the fly-zones through the assistance of timing eyes. However, kinetic and kinematic data that provides greater insight into how a sprinter modulates tactics in order to achieve similar velocities within the zones has gone unknown.

For instance, based on the data used in Figure 16, both fly-zones demonstrated a greater reliance on I1 as compared to the float-zone while total impulse remained nearly unchanged. In addition, it appears that practitioners may indeed be correct as I1 reaches its highest magnitudes in the second fly zone.

As a result of the information collected through the average zone velocities and the force waveforms, the FFF is indeed an advanced tactic that should be used within the SPP or Pre-Comp to isolate and exploit top speed mechanics. In addition, this type of training unit can be morphed into speed-reserve/ speed-endurance sessions through the elongation of runs, while still may 2019 techniques

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SPEED PLAY avoiding the creation of the dynamic stereotype as identified by Ozolin (1978).

Conclusion Though many of the drills discussed throughout this paper have been well established within track & field, variance in instruction and prescription continue to exist. Therefore, the purpose of this paper was twofold: First, the authors hope to promote coaching continuity through the description of drill design, cueing strategies for set-up and execution, and optimal placement within the training plan (Figure 18). Second, the authors provide ecologically-valid monitoring data that helps illuminate how these properly-instructed drills influence sprinting outcomes.

Why does this matter? In summary because sprinting, like all other forms of human locomotion, is a skill. The waveforms introduced within this paper speak to the elegance of movement quality in a way that traditional variables such as step time, length, and frequency cannot. Specifically, these waveforms demonstrate shape and scope of force production that factors into the sprinter’s technique.

The question, now, is not if there exists a universally-applicable technical model or how much strength is needed to run fast; rather, we should ask ourselves how much latitude exists in either direction from an individual athlete’s preferred movement signature before we attempt to exploit a given tactic. Perhaps the monitoring and study of stance waveforms provides us with that answer.

Acknowledgements The authors would like to thank John Abbott and Austin Smith for their efforts in supporting this project.

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Dr. Brad DeWeese is the HighPerformance Manager and Head Coach for the US Olympic Training Site at ETSU. As a coach, Brad has produced two-dozen Olympians, 7 World Champions, and over 20 Olympic & World Championship medals.

Dr. John Wagle currently serves as the Minor League Strength & Conditioning Coordinator for the Kansas City Royals. Prior to this position, John was a Strength & Conditioning Fellow at ETSU, and was the Director of Sports Performance at DePaul University.

Joel Williams is the sprints and hurdles coach at UNC Asheville, where he has produced 28 Big South All-Conference performers, 10 Conference Champions, 1 NCAA indoor All-American, 2 National Record Holders, and 3 Olympic & World Championship athletes.

Dr. Matt Sams is a sport scientist and sport science consultant. His previous experiences include work with Chinese cross-country ski, faculty membership at LaGrange College, ETSU men’s soccer, and the USOC Lake Placid Olympic Training Center’s Sport Physiology Department.

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The Bent Twig Effect A Trajectory for Growth and Development Matthew Buns, Ph.D.

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Justin Oakman photo

As the twig is bent, so grows the tree.

- Alexander Pope

I

t has been said that the journey of a thousand miles begins with a single step. This concept underscores the idea that successful seasons can have very small beginnings. High-performing coaches and athletes do not despise the small beginnings but actually show great joy to see the work begin. After all, small beginnings can bring down mighty mountains (Zechariah 4:10). The MerriamWebster dictionary defines trajectory as “the path followed by a projectile ying or an object moving under the action of given forces.â€? Put simply, trajectory refers to the path in life that an individual chooses. The ability to learn a wide variety of new motor skills throughout life is one of the most essential capacities possessed by humans (Edwards, 2011).

Understanding how track & field athletes acquire skills, and how they can demonstrate expertise effectively, is a particularly critical and useful area of coaching knowledge. Many of the same fundamental principles of improvement apply to a track athlete competing in his first race and a field athlete learning to throw the javelin.

The purpose of this article is to briefly describe highly-predictable principles that describe the process underlying performance improvement within the context of track & field skill development. may 2019 techniques

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The Bent Twig Effect The Bent Twig Effect illustrates the relationship between path and outcome and is centered on the idea that early influences have a permanent effect (Sigelman, 2012).

If you push a small twig slightly away from its normal pattern of growth, you can cause a major change in the ultimate location of the branch that grows from that twig. Pushing on a branch that is already developed has much less effect. The Bent Twig Effect is also evident in track & field.

When athletes continue to progress in a certain direction, they are more likely to reach a desired end goal. However, a slight change in trajectory can lead to significant differences in the outcomes achieved.

The path an athlete chooses will have a significant impact on the outcomes they desire in life and sport. In her book “Mindset: The New Psychology of 32

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Success,” Carol Dweck (2008) famously described two basic mindsets that are believed to significantly shape a person’s path toward success or failure. The fixed mindset assumes that intelligence and ability is static, meaning it cannot change in a meaningful way. A growth mindset, on the other hand, strives for challenge and recognizes failure not as evidence of incompetence but as a springboard for growth. In a similar manner, an individual with a fixed trajectory moves toward an unrewarding path that will not take them to achieving desired outcomes (Figure 1).

One of the most glaring characteristics of an athlete following a fixed trajectory is a lack of persistence; the athlete might appear to pursue success diligently until success no longer comes easy to them.

At this point, they fail to demonstrate a high level of self-motivation and lack

confidence in the face of setbacks. In the presence of repeated failure, the athlete with a fixed trajectory lacks mental focus and appears to give up easily. The longer a person remains on a fixed trajectory, the less likely they are to ever achieve desired outcomes because the degree of difficulty is much greater with each time segment that passes. Those who are able to master skills in track & field follow a growth trajectory and recognize that improvement and the path to success isn’t always fun.

Fortunately, making only the slightest alterations to a trajectory can have a profound effect on a person’s achievement.

When an athlete decides to follow a growth trajectory, progress will eventually follow, even though initial progress may be small.

In the presence of failure and seeming futility, expert performers carry on confident that they will figure it out.

Justin Oakman photo

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THE BENT TWIG EFFECT

Figure 1. The Bent Twig Effect.

Figure 2. Attribution Theory

As coaches and athletes alike have noticed, the trajectory toward success is not always linear. Even if goals are set with a growth mindset, that does not mean athletes will progress in a forward pattern from start to finish. There may be unexpected setbacks or times where progress stalls. This is normal, and the athlete who recognizes this holds the advantage.

Positive and informed athletes look for a possible solution to challenges rather than succumbing to frustration. Researchers have identified a link between positivity and the ability to perform. Positive emotion builds resourcefulness in ways that help athletes become more resilient to adversity and perform at a higher level.

It has been said that a bad attitude is like a flat tire—you can’t go anywhere with it! The goal is to achieve overall forward movement toward a goal without ignoring the huge efforts and setbacks that are required to make success possible. As 34

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aforementioned, success can be “messy” and is not always achieved on the first attempt or without setbacks. However, the athlete following a growth trajectory proceeds with outstanding effort and worklike intensity even though it may generate no immediate rewards.

One of the most important decisions an athlete can make is to determine the correct trajectory. The more time an athlete stays on the growth trajectory, the closer they get to achieving desired outcomes.

High performers are often motivated by the goal of improvement rather than enjoyment. The earlier an athlete makes the decision to follow a growth trajectory, and the earlier they actually take action, the greater the degree of success at achieving desired outcomes. Effective coaches will create opportunities for athletes to examine their current trajectory and reflect on whether continuing on this path will lead to the most desired outcomes.

Attribution Theory According to Attribution Theory, for any test of skill or competence, there are four possible explanations for the outcome, regardless of success or failure (Thomas, Lee, & Thomas, 2008). These attributions (Figure 2) have two dimensions: locus of control (internal or external) and level of stability (stable or unstable).

The preferred attribution is effort, because effort is related to practice.

Furthermore, effort is under an athlete’s control and is variable (can change).

The law of practice is one of the most highly reliable laws in learning theory.

Performance improvement continues as long as practice continues, but the rate at which it occurs gradually and predictably diminishes over time (Evans, Brown, Mewhort, & Heathcote, 2018). Thus, the object is to have an athlete give maximum effort all of the time. Expecting to improve without any effort is like waiting for a ship at the airport.

Task difficulty is the coach’s responsibility. Coaches should provide practice tasks that are challenging but feasible.

Whenever possible, athletes should have a 50-50 chance of “success” when they give maximum effort. Tasks that are too easy can be boring and do not help athlete’s master new skills. Tasks that are too difficult do not help them learn and may be overly frustrating. The lawful pattern of improvement shows regularity for virtually all track & field skills (although the exact rate will change depending on the skill and learner).

Ability is often viewed as talent. Talent is often not a powerful predictor of performance in many track and field events. However, talent is often presented as a major factor by athletes (particularly those with a fixed mindset). If talent was the most important factor in performance, practice and coaching in general become unimportant.

The ability to do a task changes slowly with practice, which is why it is viewed as stable. Ability does not change from moment to moment. When acquiring new track & field skills, most athletes experience their greatest rate of improvement early in process, whereas once the skill has been learned to some moderate level of performance, further improvement becomes increasingly difficult.

Luck is often used as an explanation

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for outcomes. For example, athletes with a fixed mindset often say luck explains victory. Athletes on winning teams usually expect a win, even after a loss. Athletes on losing teams tend to predict a loss, even after a win. Luck is both external and unstable and, therefore, a poor choice. The assumption with attribution theory is that athletes learn attributions, and the most appropriate attribution is effort.

Begin with the End in Mind Start each season with the end in mind.

The world is full of people who can start a task, but it is the finishers in track & field who are a premium. Outstanding coaches do not only emphasize the end goal or outcome—they also encourage athletes to “find their mark,” an intermediate goal or objective. When athletes focus on a shortterm objective and move toward it, they are more likely to stay on a growth trajectory. If you know anything about bowling, you know that each lane has on it a series of marks that lie just a few feet in front of 36

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the bowler. Good bowlers use these marks to aim their bowling balls so they ultimately strike the pins in the proper place.

Ironically, the expert bowler doesn’t aim at the pins; she focuses on the mark. If you only aim for the pins, you won’t hit your ultimate goals. Encourage athletes to head toward that mark, and their ultimate goals will come into view.

To summarize, the decisions an athlete (or a coach for that matter) makes during the initial days or weeks of practice shape the trajectory of their season, and ultimately the trajectory of a career. Thus, it is important for athletes to develop good habits early in the season. Here is some basic advice to help athletes begin the season on a growth trajectory with the end in mind: Identify desired outcomes in life and in track & field or cross country.

Determine whether the current trajectory or path is leading to those outcomes.

If not, identify what actions and steps are required to progress down a growth trajec-

tory.

Make an immediate decision, take immediate action, and take the first step on a new growth trajectory.

Stay focused, determined, and disciplined in moving down the path of a growth trajectory. This may be the most diff cult challenge to face. It’s human nature to want to stick to things we know and are comfortable with. Athletes should examine their own comfort zone and remain committed to expanding that comfort zone to reach desired outcomes.

Success in athletics requires a great deal of effort, preparation, and feedback. Many athletes and coaches want to be great until they learn what is required to be great.

Following the 2016 Summer Olympic Games, swimming legend Michael Phelps, when asked about the key to his success, stated, “In order to get to where you want to go, you need to be willing to do the things that other people aren’t willing to do.”

More individuals would probably train Justin Oakman photo

harder if they knew, or only had some type of sign, that the hard work would pay off.

However, you do not always know what the outcome of your hard work will be.

Let obedience lead to the next step, and encourage athletes to go out on a limb because that is where the fruit is! After all, the tallest oak tree in the forest was once a little nut that simply held its ground.

Athletes interested in growth and development are able to start their own engine and arrive to practice with their motor running and ready to be their best. This means that athletes must expend considerable effort and demonstrate mastery — sometimes at a level previously unexplored. There is no textbook for this type of work. However, the rewards for success are great.

References Dweck, Carol S.. (2008) Mindset :the new psychology of success. New York : Ballantine Books.

Edwards, W. H. (2011). Motor learning and control: From theory to practice. Belmont, CA: Wadsworth Cengage

Learning.

Evans, N. J., Brown, S. D., Mewhort, D. J. K., & Heathcote, A. (2018). Refining the law of practice. Psychological Review, 125(4), 592-605.

Sigelman, Carol K & Rider, Elizabeth A & Sigelman, Carol K. Life-span human development. 7th ed (2012). Study guide : Life-span human development (7 ed).

Wadsworth, Cengage Learning, Belmont, California.

Thomas, K. T., Lee, A. M., & Thomas, J. R. (2008). Physical education methods for elementary teachers. Champaign, IL: Human Kinetics.

Matthew Buns, Ph.D., is an Assistant Cross Country and Track & Field coach and Associate Professor of Kinesiology at Concordia University, St. Paul. While competing at Concordia University, Nebraska, he was a twotime NAIA All-American and two-time Academic All-American. During his coaching tenure, Buns has helped coach 19 NAIA All-Americans in Track & Field and two NAIA All-Americans in Cross Country.

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Selected Segment

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KIRBY LEE IMAGE OF SPORT

Dynamics in Javelin Throwing Andreas V. Maheras, Ph.D.

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he javelin thrower and their implement can be considered as a system moving in space and time, with a proper synergy between the two resulting in the maximum distance thrown. The javelin thrower themself can also be considered as a system — a system which is made of a number of body parts having their own mass and their own mass distribution, with the neuromuscular system being in charge of controlling the interaction of those individual parts. From a dynamic point of view, the final product of that interaction is the result of another interaction between muscular forces and external forces — the latter being the inertia of the implement and the body parts and also the force of gravity. General knowledge about movement interaction and coordination is essential for maximizing the positive mechanic effect on the throw.

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Leg Dynamics A well-known axiom of all the throwing events states that effective throwing relies heavily on the contribution of the legs. In javelin throwing, a few factors that are crucial for optimal performance include controlling the velocity of the system in the various phases of the throw, the position(s) of the body and that of the javelin, the acceleration path during the delivery of the implement, and control of the javelin at the moment of the final effort.

Back leg. Hypothesizing that there is a need for high system speed before delivery, the back leg’s action (along with that of the upper body) should ensure minimal deceleration of the system’s velocity during the final stride. Decreases in the speed of the body may range between 0.31 to 0.67 m/sec. (Bartonientz, 2005).

A sound technique should be geared towards reducing deceleration and “back lean” at the moment the right foot lands, following the execution of the impulse step. In turn, the movements preceding the impulse step will affect the actual position of the upper body at the moment the right foot touches down for the final stride. A high drive of the right leg during the impulse stride will most probably lead to a pronounced, backwards leaning upper body (figure 1). The explanation for this lies with Newton’s third law (action-reaction) while the thrower is airborne. A better alternative may be one where, during the impulse, the left foot actively grabs the ground while the right leg is executing a shorter duration, scissors-like impulse.

The idea of a backward lean of the torso may still be a misunderstood concept. It was considered that such a lean would enable the thrower to increase the path of force exertion on the implement. However, for most throwers, the greater the backward tilt of the torso at the moment of landing on the right foot, the greater the loss of the system’s velocity as previously implied. In addition, a reduced back lean will also contribute to a higher carry of the javelin (figure 1), which has shown to be important in improving the aerodynamic position of the javelin at the time of release (Leigh et al., 2010; Best et al. 1993; Best et. al., 1994).

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Although several years ago the thought of increasing the velocity of the system — or even keeping it constant — after the execution of the impulse step was considered unattainable, the possibility of that occurring may still exist. As the thrower executes an active impulse with the left foot, she keeps the upper body in a neutral and a rather vertical position. Following that impulse and during the forward “hovering” phase, the center of mass (c.m) is moving pretty much horizontally, with no appreciable upward or downward movement. The thrower’s big goal at this time is to maintain her horizontal velocity while keeping the c.m. unchanged. However, there is a big danger of slowing down upon landing on the right foot. Two actions that may prevent that from happening are a) the actual landing to occur exclusively on the toes of the right foot and b) with a backwards pulling or “pawing” action on the part of the right foot as it is about to land. Therefore the javelin thrower thinks of pulling backward with her right foot, as if to increase horizontal speed. She normally may not succeed at increasing horizontal speed, but by thinking of pulling back with the right foot and of gaining horizontal speed,

she will actually succeed at maintaining horizontal speed, which was a minimal original goal (Dapena, 2019).

Following those two actions, it is going to be hard for the thrower to continue pushing backward with the right foot for much longer after the left foot plants.

This is because, ideally, the right leg will already be in such a backward position by then. One cannot push back any more because the right leg is at or close to the limit of its backward range of motion.

In fact, almost immediately after the left foot plants, the right foot will be touching the ground only with the right toe, and immediately after that, the right foot will drag forward, it will literally slide forward (more or less) on the ground, contacting the ground only with the toe and/or with the upper and outward (leather) part of the shoe instead of with the sole. While the right foot slides forward, the laws of mechanics say that it cannot be making any backward force on the ground any more. It will have to be making a forward force on the ground through friction, as well as a downward force on the ground. The forward horizontal force made on the ground through friction (dragging) will make the ground exert, by reaction, a backward reacAndreas Maheras PHOTO

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tion force on the foot (see figure 2). The downward vertical force made on the ground by the foot will make the ground exert an upward ground reaction force on the foot. Both of these forces are probably good, because they will help to promote clockwise motion of the whole system (in the view from the right side of the thrower). These two forces may not be hugely important, but if anything, they will be positive for the overall throwing action.

As for the significance of the maintenance of high system speed during the final strides, analysis data of velocities of the center of mass for a full approach show that top athletes exhibit higher body velocity at the beginning of the delivery phase and that they also achieve 42

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the longest throws when their run up speed is at its highest. Generally, the higher speed levels and longer impulse strides lead to longer distances thrown (Leigh et al., 2010).

Regarding the actual position of the right foot, after its final landing, in relation to the direction of the throw, that varies between almost zero degrees, i.e., in line with the direction of the throw, and ninety degrees, i.e., perpendicular to the direction of the throw. The first method may reduce the influence of a right leg drive (if any), whereas the latter may lead to knee injury caused by an inward bending. Therefore a right foot position somewhere in between, at forty five degrees, may be the preferred right foot landing position for many throwers

(Sing, 1984).

Front Leg. The action of that leg is power demanding, as it provides the means by which the thrower will abruptly stop her forward movement and initiate the throwing action. Both from a mechanical and a physiological point of view, a generously flexed front leg will not properly create the conditions for the thrower to achieve the desired “arch� position. Depending on the instance of the delivery phase, any observed knee flexion throughout this phase will vary a few degrees, with 180 degrees being a straight leg position. Smaller left knee flexion values (and high knee stability) are associated with higher performances (Mahmoud, 2010; Moriss et al., 1997).

The front leg should be planted as fast as KIRBY LEE IMAGE OF SPORT

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Figure 1. Back lean and javelin carry of three different athletes at right foot contact during the final stride. From left to right, least to most optimum (adapted from Bartonietz, 2005).

Figure 2. Clockwise rotation (c) of the thrower + javelin system about its own center of gravity (cross inside yellow circle) shortly after the left foot planting. Also shown, backward ground reaction force (a) and upward ground reaction force (b).

possible while the thrower should strive to limit any constraints in regards to the velocity of the system, the position of the front leg at the moment the back leg touches down, along with the action of the right foot itself. Time values as low as 0.14 sec. have been recorded (Morris et al., 1997) between right foot and left foot landing during the throwing stride.

A firm front leg will allow for a short translation of the of the c.m during the final effort. Experimental data (e.g., Morriss et al., 1997) have shown the “firmness” of the front leg to be a reliable criterion for performance improvement. Another factor determining the effectiveness of the front leg is the length of the throwing stride itself.

High caliber throwers tend to employ a longer throwing stride, whereas throwers of lesser abilities employ shorter 44

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strides which are also characterized by steeper ground reaction forces. From a mechanical point of view, as the front leg touches down, the ground force which is created at that moment passes through the c.m and in turn results in the creation of a counterclockwise angular momentum of the upper body.

At this moment, the direction of the force is at a high angle (see figure 3).

This provides the foundation for the creation of the desired muscular tension and the “arch” position, which is created by the combination of an inert shoulder and arm, coupled with the aforementioned angular momentum.

As the movement continues, the ground force will quickly change its direction and size. As far as the direction, that will act along the front leg, whereas the size of it will reach its

maximum. The direction of the angular momentum changes to clockwise (figure 2) and as it occurs, it further enhances the thrusting of both the chest and the throwing arm, culminating with the projection of the javelin.

This way there is a transfer of angular momentum from the body to the throwing arm (LeBlank & Dapena, 1998). The angular momentum and its direction will affect the performance outcome particularly as it relates to the influence the front leg has upon it. As that leg flexes, there is a reduction in the size of the ground reaction force as well as a change in its direction.

There is an observed strong dependence between kinematic parameters (like joint angles and velocities), and performance levels — so much so that it is thought that differences in the for-

Figure 3. Schematic representation of the magnitude and direction of ground forces on the left foot, during the delivery of the javelin (adapted from Bartonietz, 2005).

Figure 4. Ground reaction forces following final left foot contact (adapted from Bartonietz, 2005).

mer can explain differences in the latter.

From a technical point of view, those differences manifest themselves as, a) a smaller size ground reaction forces at right foot touch down after the impulse step, b) a more dynamic landing of that same foot with less backwards tilting of the torso, c) a maintenance or even increase of the system’s velocity due to that dynamic activity of the back leg, d) a very dynamic activity of the front leg which generates high ground reaction forces and results in a rapid deceleration of the system and a dramatic energy

transfer from the body to the javelin (Bartonietz, 2005).

The high demand placed on the front leg may limit the number of throws which can be attained during practice.

In top athletes, the greatest amount of deceleration occurs during the first third of the delivery phase as revealed by ground reaction force data (figure 4). A controlled throw in practice with a relatively low body speed of say 4m/sec., may eventually decelerate to 2 m/sec. in about 0.14 seconds as the left foot plants.

This change in energy is approximately

three and a half times smaller than that experienced in competition (Bartonietz, 2005). Therefore, as the run up speed increases during competition throwing, the energy demands also increase.

On the other hand, the time to transfer the energy remains virtually constant, and this way the overall power required on the part of the thrower is fourfold because of the square influence of the velocity of the body on the energy and, in turn, on the power. From a mechanical point of view, this explains why less powerful athletes, who demonstrate may 2019 techniques

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Figure 5. Velocities over time of the center of mass of the forearm, the upper arm, the trunk and the whole body between the instance of left foot planting and release (adapted from Bartonietz, 2005).

an acceptable throwing pattern during practice and at lower speeds, fail to do the same during a full approach.

There is simply not adequate amount of power (Bartonietz, 2005).

Upper Body and Throwing Arm The momentum transfer theory is used to explain the velocities of the various body segments over time and expresses the impulse transmission to the implement. The big picture in applying this theory for a javelin thrower is that initially the thrower+javelin system is accelerated to acquire momentum (mass x velocity) and subsequently, a deceleration occurs which first includes the legs and the lower parts of the torso, resulting in the acceleration of the upper parts of the torso.

In turn, the upper parts of the torso also decelerate while the upper arm, forearm and hand, in that order, also accelerate ending up in a “snapping” projection of the javelin.

The seamless execution of the sequence of the above described movements will result in a smooth, not forced throw, which is “effortless” and is the result of an effective use of momentum transfer. This transfer 46

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occurs from muscles situated nearer to the center of the body (proximal) to those situated away from the center of the body (distal), following an optimal delay in their activation, and based on the mechanical interaction between the proximal and distal muscles involved.

On the other hand, that seamless execution does not depend on the transfer of momentum alone in order to occur.

Although effortless, in terms of lack of unnecessary and disorderly muscular activity, the delivery does require intense and coordinated muscular activity. This implies the development of skills such as the ability to delay the action of the throwing arm (Bartlett et. al., 1996) and generally, develop a “feel” for the javelin. The delaying of the arm in particular has a significant impact for performance as it is central in developing the necessary pretension and stretching just before the javelin release. The maximum of the “bow” phase can be considered the moment in time when the upper arm starts rotating internally or the moment when that arm stops rotating externally and the final acceleration of the javelin begins.

At that exact time, the potential of the stretch-shortening cycle is employed,

and there is an optimal body speed at which this cycle would work most efficiently. It has been hypothesized that a great amount of the difference in distance thrown between low speed approaches and higher speed approaches is due to a compromised efficiency of the musculotendinous system to indeed utilize the stretch — shortening cycle in lower speed conditions.

Energy Flow Considerations During the final effort which follows the planting of the front leg, the traditional model of energy flow as described by Kreighbaum & Barthels (1981), argues about a proximal to distal energy flow, as described above, and it states that the distal limb, the forearm, will accelerate because the proximal limb, upper arm, will decelerate to ensure appropriate momentum transfer. On the other hand, Bartonietz (2005) argued that it is not the proximal limb that decelerates in order to accelerate the distal limb, but it is the other way around. Invoking Newton’s action-reaction law, he stated that the proximal limb decelerates as a reaction to the acceleration action of the distal limb. Therefore it could be that distal

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selected segment limbs affect the proximal limbs more than the other way around (also in Kulig et al., 1983).

This possibility may be essential regarding the overall final effort in javelin throwing and the movement of the upper body in particular. As the front leg plants, the velocity of the torso is virtually constant (figure 5), and will be influenced by the reaction of the arm acceleration. If the thrower, employing the proximal to distal order of energy flow, stops the forward movement of the trunk, in order to provide “proper” energy transfer to the arm, she will fail to work through with the upper body and instead, she will remain in a generally upright position, which will result in a decrease in release velocity, a high angle of release and a lack of a rolling in of the elbow.

Therefore, an observation of the velocity changes of the various limbs may be sufficient in evaluating the individual throwing pattern of a thrower, but may not be sufficient in evaluating the contribution of the various body segments to the throwing movement itself.

Conclusions The javelin thrower needs to be trained to take advantage of the dynamics of her body segments so she can generate the maximum power and energy. A few important technical points to consider avoiding include, a) a low speed run up, or a run up that leads to a passive instead of an accelerating penultimate stride, b) an inactivity of the right leg which is manifested with a marked loss of speed and a lack of pushing the right side forward, c) a planting of the front leg in a flexed position, d) a steep planting angle of the front leg, e) an untimely delivery, or f) a premature movement of the throwing arm with the ensuing deficit in muscular tension.

The front leg in particular requires conditioning, both technical and muscular, to be able to bring the system to a quick stop. General and specific power can be developed by strength exercises and by practicing under approach speeds, that match those of competition.

The amount of body speed lost during the delivery phase as a result of a firm block, can serve as a gauge of throwing efficiency, taking into account the initial speed. Because of the lower power demands, the lower the initial speed, the

easier it is to rapidly decelerate, compared to achieving the same deceleration at higher initial body speeds. Generally, but not always, the lower the velocity of the center of gravity at release, the higher the velocity of release, an observation that accentuates the importance of the action of the front leg.

References Bartlett, R., Muller, E, Lindinger, S. Brunner, F., & Morriss, C. (1996). Three dimensional evaluation of the kinematic release parameters for javelin throwers of different skill levels. Journal of Applied Biomechanics, 12, 58-71 Bartonietz, K. (2005). Javelin throwing: An approach to performance development. In Biomechanics in Sport, ed.

Zatsiorsky, V. pp. 401-434.

Best, R., Barteltt, R., Morriss, C. (1993).

A three dimensional analysis of javelin throwing technique. Journal of Sports Science, 11, 315-328.

Dapena, J. (2019). Personal communication.

Kreighbaum, E, & Barthels, K. (1981).

Biomechanics: A Qualitative Approach for Studying Human Movement.

Minneapolis, MN. Kulig, K., Nowacki, Z., Bober, T. (1983). Synchronization of partial impulses as a biomechanical principle.

In: Biomechanics VIII-B. Proceedings of the 8th International Congress of Biomechanics.

Leigh, S. Liy, H, & Yu, B. (2010).

Associations between javelin throwing technique and aerodynamic distance. International Symposium on Biomechanics in Sports. Conference Proceedings Archives, Vol. 28.

Leigh, S. Liy, H, & Yu, B. (2010).

Associations between javelin throwing technique and release speed.

International Symposium on Biomechanics in Sports. Conference Proceedings Archives, Vol. 28.

Mahmud, E. (2010). Movement analysis for javelin throwers in the Quatar 2009 championships. International Symposium on Biomechanics in Sports.

Conference Proceedings Archives.

Morriss C., Bartlett, R., & Fouler, N. (1997). Biomechanical analysis of the men’s javelin throw at the 1995 world championships in athletics. IAAF New Studies in Athletics, 12:2, 31-41.

Morriss C., Bartlett, R. (1994). The height of carry of the Javelin and its rela-

tionship with throwing performance.

Proceedings of the International Congress of Applied Research in Sports. Helsinki, Finland, 133-136.

Sing, R. (1984). The dynamics of the javelin throw. Reynolds publishers, Cherry Hill New Jersey.

Dr. Andreas Maheras is the throws coach at Fort Hays State University in Kansas and a frequent contributor to this publication.

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2019 National Indoor Track & Field NCAA Division I

Lance Harter Arkansas Women’s Head COY

Mike Holloway Florida Men’s Head COY

Bryan Compton Arkansas Women’s Assistant COY

Justin St. Clair North Dakota State Men’s Assistant COY

Kayla White North Carolina A&T Women’s Track AOY

Grant Holloway Florida Men’s Track AOY

Yanis David Florida Women’s Field AOY

Payton Otterdahl North Dakota State Men’s Field AOY

Dustin Imdieke Adams State Women’s Assistant COY

Ray Robinson Tiffin Men’s Assistant COY

Caroline Kurgat Alaska Anchorage Women’s Track AOY

Mobolade Ajomale Academy of Art Men’s Track AOY

Fatim Affessi West Texas A&M Women’s Field AOY

Isaac Grimes Chadron State Men’s Field AOY

Lane Lohr Washington Women’s Assistant COY

Al Carius North Central Men’s Assistant COY

Gabby Noland Loras Women’s Track AOY

Dhruvil Patel North Central Men’s Track AOY

Eka Jose Washington Women’s Field AOY

David Kornack UW-Eau Claire Men’s Field AOY

NCAA Division II

Damon Martin Adams State Women’s Head COY

Jud Logan Ashland Men’s Head COY

NCAA Division III

Nate Hoey Williams Women’s Head COY

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Frank Gramarosso North Central Men’s Head COY

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Athletes and Coaches of the Year NAIA

Doug Edgar Indiana Tech Men’s Head COY

Brian Whitlock Wayland Baptist Women’s Head COY

Ed McLaughlin Concordia Women’s Assistant COY

Malcolm Dias William Carey Men’s Assistant COY

Anna Shields Point Park Women’s Track AOY

Tre Hinds Wayland Baptist Men’s Track AOY

Kamberlynn Lamer Dakota Women’s Field AOY

Jordan Downs Bethel Men’s Field AOY

NJCAA

David Schenek Barton CC Women’s Head COY

Nigel Bigbee Iowa Central CC Men’s Head COY

Mark’Quis Frazier Barton CC Women’s Assistant COY

Drew Mahin Cloud County CC Men’s Assistant COY

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Nehemiah Too Colby CC Men’s Track AOY

Grace Chinonyelum Cloud County CC Women’s Field AOY

Jonathan Ply Central Arizona Men’s Field AOY

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Spring Maintenance of Track & Field Facilities Mary Helen Sprecher - American Sports Builders Association

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he snow and ice have receded and coaches everywhere are taking a look at their tracks — and not liking what they see.

It’s not surprising. Cold weather and freeze/thaw action aren’t known for being kind to outdoor facilities and ultimately, no matter how good a track is, it’s going to need some TLC in the spring. So where do you start?

On the surface: Walk your track several times — without distractions. (We’re looking at you, people with your eyes welded to your phones.) Look at all the lanes, all the lines and all the markings. Check the surface for bubbling, cracking, wearing, loose material or places where markings seem to be wearing out. Are you seeing areas that seem to be higher or lower?

Make a list of all your concerns. Take photos and each out to your track installer and ask them to take a look at the problem area(s). It may be something they can fix easily and inexpensively (or for no charge at all, depending on the newness of the track). The only precaution: don’t try to do it yourself, since that may exacerbate the problem. And don’t ignore it; track sur-

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faces aren’t self-repairing and an aesthetic problem can be corrected before it turns into a tripping hazard that causes injury to an athlete.

On the Fence: Check fencing around fields; look for bulging fabric, sagging rails or places where gates are dragging across the surface of the track. This is an area where a few quick repairs can make a big difference in the overall look of a facility — to say nothing of the safety factor.

In the Field: Next, it’s time to check your field event structures. Vaulting, jumping and throwing structures should all be examined carefully and repairs made (or replacements ordered) if necessary.

Investing the time now can save a lot of embarrassment (and potential injury) in practice or even worse, at a meet. Aesthetic fixes, such as paint touch-ups, can also be performed at this time.

You’ll want to check the level of sand in sand pits and top up if necessary. Sand pits should be secured with locking covers, which keeps them free of debris when they’re not in use — and keeps athletes safer. A periodic sand change is also a good idea, and spring is a good time to do it.

A good spring maintenance plan is simply one part of your annual plan, and good recordkeeping is an enormous part of that. From year to year, being able to track what was done and when and where can help you with planning and budgeting for repairs and replacements. It can also give you an idea of how often certain items need to be reordered or restocked. Should you move on to another position, you’ll want to make sure your successor has these records; it will save him or her the trouble of having to start from the beginning without guidance.

Note: The American Sports Builders Association (ASBA) is a non-profit association helping designers, builders, owners, operators and users understand quality construction of many sports facilities, including sports fields. The ASBA sponsors informative meetings and publishes newsletters, books and technical construction guidelines for athletic facilities including running tracks and sports fields. Available at no charge is a listing of all publications offered by the Association, as well as the ASBA’s Membership Directory. Info: 866501-ASBA (2722) or sportsbuilders.org