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Just Fly Performance Podcast Episode #39: Dr. Ken Clark

This week’s guest is Dr. Ken Clark, professor of kinesiology at West Chester University, PA.   Ken is one of the top experts on speed in the world today, both from a research and practical perspective.

Ken is not only a researcher, but is also a coach and consultant in the world of speed, so he is able to apply this work in a practical setting.   I’ve heard Ken on a number of performance related podcasts, so I was excited to get him on mine and answer a number of questions I had in the world of building speed in both the context of track and field, and team sport.

Based on the number of times I’ve heard him on these shows, I can really say that Ken Clark might be the most in demand speed expert in the world.

On the podcast today, we’ll cover a variety of topics, including sprint cues, relationships between top-end speed and acceleration, individualizing speed training, sprint drills, resisted and assisted sprint training, and more.   Of particular interest is the in-depth approach Ken takes to addressing speed development in team sport through the compete-technique-compete model, mirror and reaction drills, and more.

This talk is an amazing addition to the already incredible lineup of guests in the world of speed and power development we’ve had thus far.

Today’s episode is brought to you by SimpliFaster, supplier of high-end athletic development tools, such as the Freelap timing system, kBox, Sprint 1080, and more.

Just Fly Performance Podcast Episode #39: Dr. Ken Clark


Key Points:

  • Ken’s athletic background and transition into coaching and research
  • The “two-mass” model of sprinting and related applications in training
  • Relationships and similarities between acceleration and top end speed
  • Using “punch” as an acceleration cue
  • Simple ways to approach individualizing speed training
  • Common sprint drills that coaches cue that are counterproductive
  • Cues to avoid in top-end speed
  • Thoughts on resisted and assisted sprint training
  • Ideas of sprinting being built around the attractor length of the hamstring
  • Team and field sport applications for speed development
  • Mirror and reactive speed drills for team sport athletes
  • The Compete-Technique-Compete ideal


“Competitive sprinters have better upright posture, they have a higher knee lift, more aggressive down-stroke, and they have a stiffer ground contact… we need to train for posture, mechanics and stiffness”

“There is no doubt that the faster sprinters had a greater velocity of the foot and lower limb, both down and back into the ground (negative foot speed)”

“Elite sprinters could not only accelerate the foot down into the ground faster, they could decelerate it once it was on the ground faster”

“The better sprinters would strike the ground on the track spike so to speak… as they loaded their foot their heel would come down a little bit…. I teach runners that you need to strike on the ball of the foot, and you need to strike stiff”

“Developing stiffness at the foot ground contact, at the ankle and all the way up the chain is something that every athlete needs, whether they are a track athlete or a field sport athlete”

“I think that always having the ability to get very explosive hip action, hip flexion-extension is very important both in acceleration and top end speed, it’s just that the type of muscle action differs.  It’s very concentric at acceleration, and it’s much more reactive during ground contact at top speed.  Ankle stiffness and foot ground contact stiffness is going to be important all the way through the race.”

“The best athletes have some unifying strategies from acceleration through top speed (posture, front-side dominant strategy, aggressive scissoring of the thighs)”

“Once a sprinter loses their front-side mechanics from step one, or step two, that it’s hard to regain front-side mechanics further down the track”

“If an athlete can’t demonstrate proper posture, frontside mechanics, or ground contact when they are upright, how are they going to do it at an angle when the demands on posture are harder”

“If “push” isn’t working for you in your toolbox, then go to “punch” (when coaching acceleration)

“The thigh switch (boom-boom) is self-limiting; you can’t have any backside mechanics in that drill or you fall on your face”

“I’ve totally gone away from the wall cycle drill…. In best case it had no transfer at all, and worst case scenario it made my athlete overthink… I’ve replaced most cyclical drills with thigh switch drills or straight leg frontside drills”

“To accelerate effectively, you need to push down and back as hard relative to your bodymass as possible.  If we can load a runner up with a push sled or a pull sled to do that, that makes sense”

“The bugaboo with overspeed training was that you couldn’t dial in precise resistances for it.  The 1080 is going to open up a new world with specific overspeed, and specific velocity profiles in the sprint… mechanicsms like the 1080 are going to be able to elicit that type of drive that you really can’t get in any other situation”

“From a coaching standpoint, I want to see that “whip from the hip” increase over time”

“We start with a competitive drill… we want them going at full speed, that’s the best way to get these field athletes faster.  The we’ll take what these athletes were demonstrating in the compete section, and we’ll work on it in a technique based section… we’re doing a lot of observing, what were the main errors being made?… We’ll take our observations, and then we’ll do closed drills…. Then we’ll go to compete 2, it’s a more progressed version of that original compete drill, were hoping to see some improvements off of that original compete section.”

“Team sport athletes tend to spin their wheels too much and not cover any ground”

“When those plays happen (top speed sprinting) you had better be able to do it, because those are game-breaking plays”

About Ken Clark

Dr Ken ClarkDr. Ken Clark is an Assistant Professor in the Department of Kinesiology at West Chester University. Dr. Clark teaches Biomechanics and Kinetic Anatomy at the undergraduate level, and teaches Motor Learning at both the undergraduate and graduate level.

Dr. Clark’s research interests include the mechanical factors underlying athletic performance and injury mechanisms, as well as the integration of motor learning with biomechanics as it relates to movement skill acquisition. He has peer-reviewed publications in journals such as the Journal of Applied Physiology, Journal of Experimental Biology, Scandinavian Journal of Medicine & Science in Sports, and the Journal of Strength & Conditioning Research.

In addition to teaching and conducting research, Dr. Clark has over a decade of strength & conditioning coaching experience. He has coached in the private sector (Summit Sports and CES Performance), the high school level (Jesuit Prep in Dallas TX), and in the collegiate setting (Dickinson College, Haverford College, Villanova University). Dr. Clark has certifications from the NSCA, USA-Weightlifting, and USA Track & Field.

Dr. Clark received his PhD in Applied Physiology and Biomechanics from Southern Methodist University in Dallas in 2014. He is a Golden Ram alumni, having completed his Master’s Degree in Kinesiology at West Chester University in 2009. Dr. Clark completed his BA degree in Psychology at Swarthmore College in 2003, where he was an All-Conference running back for the football team.

One comment

  1. Fine podcast. I got the idea that a concept of negative foot velocity in the sprint step is not a focus in the two-mass model. More attention is toward a stiff lower leg, with little ankle flexion at toe-off and immediate hip flexion toward major front-side action.

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