Questions & Answers on Peter Weyand’s Research

This is part 3 of the Freelap Friday Five Series, Season Three. To review the past 34 interviews, click here.

Part 1 was Jeff Cubos, Chiropractor and Performance Therapist

Part 2 was John Godina, World Athletics Center founder & Elite Shot Putter

Let’s get right to the point: You want to get faster, so what can we learn from Sport Science?

For starters, Dr. Peter Weyand is widely recognized as one of the world’s leading scholars on the scientific basis of human performance. His research on the mechanical and physiological basis of sprint exercise performance continues to advance scientific understanding and shape contemporary training practices.

Dr. Weyand is an Associate Professor of Applied Physiology & Biomechanics and Director of the Locomotor Performance Laboratory at Southern University in Dallas, Texas. Their unique testing facilities at the Locomotor Performance Laboratory have made the performance lab a draw for world-class speed athletes from across the globe. 

You can check out their YouTube channel at http://www.youtube.com/user/LocomotorLabSMU

Instead of asking Dr. Weyand the questions, I approached this FFF article by researching his answers from sourcing previous lectures, videos & journals.  I started with 5 questions, but soon expanded to 7.

Feel free to comment below.

Peter Weyand Rice Speed Symposium

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7 Scientific Answers to Common Coaching Questions

Freelap Friday Five

Q1. Is sprint running primarily an acquired skill or innate ability?  Are sprinters born, and not made?

Answer:  Sprint running is a complex skill whose execution depends directly on the musculoskeletal biology of the athlete. The ability of sprinters applying ground forces of 4-5 times the body’s weight in less than one-tenth of a second without losing their balance, while reversing the vertical direction of the center of mass, and with negligible fluctuations horizontal velocity during each stance phase requires both great skill and high-level musculoskeletal function.

The critical question for coaches and athletes is to what extent both the skill and musculoskeletal function aspects of speed are trainable. Clearly, training can improve speed, but despite the fundamental importance of speed for athletic performance broadly, the data available for quantifying and understanding training-induced improvements in speed is surprisingly limited.

Researchers can begin to document and better understand the extent of the gains in speed that are possible through:

  1. regular high-speed running
  2. strength training
  3. improved motor control

Q2. What are the mechanical requirements for achieving fast running speeds?

Answer:  The key to human speed is simple: applying large mass-specific forces to the ground quickly.

One of the most appealing aspects of the state of knowledge in this area is how available this essential information is to coaches and athletes. The biological basis of movement and performance is extraordinarily complex when one considers all the events that occur from neural activation to muscular force production to the musculoskeletal transmission of force to the running surface. However, as complex as the details of motor control, force production and delivery are during sprinting, a simple, informative and valuable take-home message exists for coaches – speed is all about hitting the ground hard and fast.

Q3. Which muscles or muscle actions should a coach focus on while training away from the track?

Answer:   The lower limb extensors: ankle, knee and hip; i.e., the muscles that straighten and extend the limb into the running surface and support the body’s weight against gravity during the stance phase.

Techniques that enhance ground force application, but do not increase the body’s mass are likely to be most effective.

The specific exercises can take several books or blog articles to explain.

Q4. What is the relative importance of stride frequency vs. stride length for top speed running?

Answer:   Speed is often considered as the product of stride length and stride frequency, which, of course is fully accurate, mathematically.

However, from the standpoint of the relevant science, both physics and musculoskeletal biology, we have found that conceptualizing speed in terms of forces applied to the ground facilitates greater understanding.  This is true for several reasons:

  1. First, applying large, mass-specific forces to the ground quickly is the athletic attribute that determines how fast athletes can run. Nearly all of the difference in speed between different individuals is attributable to what occurs during the contact or ground force application phase.
  2. Second, ground force application can be directly related to muscle, tendons and bone function whereas stride lengths and stride frequencies cannot be.
  3. Third, as detailed in Weyand’s 2000 paper on sprint mechanics5, existing data indicate that both the greater stride lengths and frequencies of faster runners result from the application of greater mass-specific ground forces in shorter periods of time.
  4. Fourth, stride lengths and frequencies are not fixed fitness or performance characteristics per se, but rather are co-selected in accordance with the duration of the aerial and contact phases of the stride for different runners and in different gaits6.

Q5. Is dorsiflexion of the ankle joint prior to ground contact beneficial and if so, why?

Answer:  Active dorsflexion by the runner using the ankle flexors before foot-ground contact may not be harmful to performance, however, queuing athletes to dorsiflex as a strategy to improve performance makes little sense for the following reasons:

Upon landing, and throughout the earlier portions of the stance phase, the weight of the body weight loads the ankle extensors and Achilles tendon with enormous forces, forcibly dorsiflexing the ankle. The gravitational forces that load the calf muscles and Achilles tendon during the stance phase are at least 10 times greater than the forces the flexor muscles can generate to dorsiflex the ankle prior to foot-ground contact. Accordingly, while actively dorsiflexing the ankle via flexor contraction before landing may not impair performance, any flexion accomplished in this manner is almost certainly functionally and mechanically irrelevant given the extent of gravitational loading that occurs subsequently in the stance phase.

Q6. What is the importance of arm swinging in sprinting?

Answer:  Once a runner is up to speed, the arms swing largely like passive pendulums, providing balance, minimizing center of mass energy losses and conserving the body’s momentum3. While arm movements are coordinated with torso and leg movements to achieve the energy transfers that minimize center of mass energy losses, they certainly do not control leg movements and have very little effect on the all-important ground reaction forces.

Arms do play a more important role during the brief acceleration phase at the start of a race than during steady-speed running, but precisely how they do so is not well understood.

Q7. Does the action of sprinting involve more of a pushing action or a pulling action against the ground?

Answer:  Conceptualizing steady-speed sprint running as either a push or a pull is not scientifically sound. Furthermore, this conceptualization could easily lead coaches in unproductive and potentially nonsensical directions. This follows from the negligible contribution of the pulling and pushing forces (i.e. horizontal) to the total external force requirement for sprinting. Once a runner is up to speed, nearly all of the ground force required is vertical in orientation while very little is required in the horizontal direction. This somewhat non-intuitive observation is a direct result of how well runners conserve their momentum and forward velocity from step to step once they are past the acceleration phase of a race.

Our precise measurements of the ground reaction forces applied both in the horizontal and vertical directions on our treadmill in the laboratory that agree well with force plate data from over-ground running illustrate this. These measurements show that during sprint running at near-constant velocities, the horizontal (i.e. pushing and pulling forces) ground reaction forces comprise very small portion (i.e. 2-10%) of the total ground reaction force required6. This percentage may be slightly greater when speed is more variable, when running into a head wind and in truly elite sprinters who have to push against slightly more air resistance. However, regardless of what the small variations from these values might be, the essential conclusion is unchanged – steady-speed sprint running requires the application of large forces downward and directly into the running surface.

This critical concept has come out of the classic work of Giovanni Cavagna and Dick Taylor1, 2, 4 published in the 1960s, 70s and 80s that nicely demonstrated that the net requirement for mechanical work and forward propulsion once a runner gets up to speed is negligible. Because runners maintain their forward momentum so effectively, they do not need to either push or pull horizontally while on the ground. They simply need to hit the ground hard enough in relation to their body weight during brief foot-ground contact periods to get back up into the air.

References

1. Cavagna, GA, Sabiene, FP, and Margaria, R. (1964). Mechanical work in running. J. Appl. Physiol. 19, 249-256.

2. Cavagna, GA, Heglund, NC and Taylor, CR (1977). Mechanical work in terrestrial locomotion: two basic mechanisms for minimizing energy expenditure. Am. J. Physiol. 233, R243-R261.

3. Mann R, Sprague P. (1980) A kinetic analysis of the ground leg during sprint running.  Res Q Exerc Sport. 51(2):334-48.

4. Taylor, C. R (1994). Relating mechanics and energetics during exercise. In: Comparative Vertebrate Exercise Physiology: Unifying Physiological Principles, edited by J. Jones. San Diego, CA: Academic, pp. 181-215.

5. Weyand PG, Sternlight DB, Bellizzi MJ, Wright S. (2000). Faster top running speeds are achieved with greater ground forces not more rapid leg movements. J Appl Physiol. 89(5):1991-9.

6. Weyand PG, Sandell, RF, Prime, DNL, Bundle MW. (2010). The biological limits to running speed are imposed from the ground up. J Appl Physiol. 108: 950-961.

  • “While arm movements are coordinated with torso and leg movements to achieve the energy transfers that minimize center of mass energy losses, they certainly do not control leg movements and have very little effect on the all-important ground reaction forces.”

    Why then is it so difficult to run with straight arms? And conversely with fully flexed elbow?

  • Jimson, I wish you had asked him about his article entitled “Sprint Exercise Performance: Does Metabolic Power Matter?” and what the training implications would be. Just because we call something “speed endurance” or “special endurance I” or “special endurance II” and Weyand says the energy systems explanation is inadequate for events under 60 seconds, does that mean the workouts are bad? Are there better workouts generated from the research that produced the article?

    • @Peter. I just wanted to be clear that these are not his DIRECT responses, but rather, answers (from his research) to common coaching questions. Feel free to expand on his research, or add any additional research (please cite the reference)

  • I’m a big fan of Weyand’s work. Not that I agree with everything he says, but that he’s doing work that has real potential application. So many scientific studies are not useful to the coach/athlete. I’ve read so many studies that sound promising in the abstract or summary, but when you get into the meat of the research you realize that the way the study was done makes it questionable for real world application. Weyand’s approach typically has validity…and if nothing else gets you questioning things as a coach/athlete.

    @Peter — That was definitely an interesting study. It hasn’t changed the way I structure training, but it has made me redefine my syntax when discussing workouts. I wrote a post about it last year: http://sprint42.com/2012/09/21/anaerobic-fatigue/

    I’ve also mentioned Weyand in a few other posts, including discussing his Anaerobic Speed Reserve concept. However, I don’t necessarily still believe everything I wrote. :) Maybe you’ll find it interesting.

    @Jimson — Weyand has definitely be an opponent to the dorsiflexion trumpet that many coaches blow. But I believe part of this is just arguing over semantics. The definition Weyand uses for dorsiflexion is actively contracting the shin to create a shin-to-foot angle of less than 90 degrees prior to touchdown. I don’t think all “dorsiflex coaches” are saying that. I personally was very “toey” (maybe touchdown with an shin-to-foot angle of ~150). When I started training under Pfaff, he quickly started harping on this, telling me to pull my toes up. But I don’t recall him ever saying I needed to get them to 90 degrees of less (maybe he did…that was almost 20 years ago). I spoke to Ken Clark last year who assists Weyand at the SMU Locomotor Performance Laboratory and he said a their general viewpoint was:

    1) elite sprinters tend to strike the ground hard and stiff with the ball of the foot (not the toes, and obviously not the heels),
    2) we do indeed see a typical ankle angle at ground contact of around ~100-120 degrees,
    3) successfully transmitting large amount of force to the ground likely requires pre-tensing the leg extensor musculature prior to ground contact and maintaining a stiff ankle complex during ground contact,
    4) Dorsi-flexion (defined as shin-to-foot angle of less than 90 degrees) at either the Touchdown or Takeoff portion of the contact phase is not required for elite sprinting.

    To me, this is more about where you lie on the spectrum of defining dorsiflexion (<=90 or is 120 still called dorsiflexion)…not a True/False answer.

  • Sprint 42: I like what you said about dorsiflexion, bc different athletes have different ankle mobilities and will have different angles at strike down. But, I disagree with Weyand on this point. Dorsiflexion is important prior to landing and it is surprising someone who does so much research would miss it. If you think about it, when the leg is dorsiflexed it is significantly shorter than with the toe out(every few degrees is almost a cm). This means first that it can move a very small amount faster, and more importantly that when it is pulled down and under the body the toe would strike the ground later, and closer to the COM, which is proven by everything else Weyand said to be important because the closer to the center of mass the foot strikes the less breaking forces and the more vertical force. This may seem insignificant, but every little thing matters in sprinting and they all add up. There is a reason sprinters don’t run on their tiptoes like ballerinas and gymnasts.

    It is also probably more important in terms of recovery. It shortens the lever and helps fire the hip flexors to allow for a faster recovery. The key is to dorsiflex the foot as soon as the foot leaves the ground. An easy way to demonstrate this is to try and curl a significant amount of weight while having your wrist cocked back and down towards the ground…it is much more difficult! Try the same weight and curl your wrist up. And finally, something that really hit me recently after reading Ralph Mann’s “The Mechanics of Sprinting and Hurdling”. He talks about how the elite sprinters do not actually reach FULL extension because they are already actively recovering the leg before the foot is actually off the ground. This goes against a lot of what coaches teach, but makes complete sense. Most expert martial artists who are taught to break boards will tell you that you want to strike fast and recover fast. This seems counter intuitive, but it allows the natural elasticity of the muscles to take over and act like a whip. To crack a whip you swing forward, but then stop and pull back to make it snap. The same thing should be done in striking the ground. More force is delivered when the leg is actively recovered and this INCLUDES DORSIFLEXING the ankle immediately after it pushes through the ground.

  • I’ve heard these arguments before and I’m not sure what to think. I assume Weyand would say that it’s not the “limiting factor”…that the heel recovery is more than adequate…and is really a result of the force being applied forcefully and quickly.

    As for me, I’d love to see more recent EMG data on someone like Usain Bolt! I’ve read Loren Seagrave where he quotes EMG studies (which I’ve read too) and illustrates it via photos of Asafa Powell. However, Powell’s biomechanics are very different from Bolt’s. The most striking difference to me is their dorsiflexion during heal recovery. The slow motion of Monoco 2011 is a good example:
    http://www.youtube.com/watch?v=4QrlPmK4B94&list=PLC692BB9EA1FDFEF0 — here you can clearly see Bolt’s ankle does not “seem” to be dorsiflexing until it’s recovered under the gluts. Moreover, his shin angle goes way above parallel during recovery…whereas Powell typically stops around parallel.

    Without EMG data, we can’t be absolutely sure when muscle are activating…but the video is not what you would expect from Mann’s interpretations.

  • Ya, I have watched that video of Usain bolt a lot. He ran 9.88 in that race and I wish there was video with the same slow motion angle in his 9.58 & 9.63 and to see how they were different technically. I think in Bolt’s case his long legs make it more difficult for him to recover as quickly. I think according to Mann’s model, which I wouldn’t say is gospel, Bolt’s technique isn’t “ideal”. Even Michael Johnson said there are a lot of things technically that he can improve on. I think that he is a rare outlier and even if you look at the analysis that Jimson just posted about his top 3 races, he spends more time on the ground and has a slower stride rate than all the other top sprinters. He more than makes up for it, clearly, with his stride length. So in that sense, he isn’t what we should be teaching others to do. That’s like teaching a normal HS basketball player to play like Shaq…they can’t because they aren’t that physically dominant. A great race to watch is the Sainsbury games… http://www.youtube.com/watch?v=37KDCSwomH4
    Kim Collins start and technique is so efficient, but he is just too small and just can’t hold off the taller runners at top speed. Look at how quickly he recovers and how frontside he is! That’s how he is still able to hang with people and still run fast at his age.

    I agree 100% about wanting to see EMG of Bolt when he runs, as well as Gay, & Blake. There is a lot more that can be done to understand all this.

  • Hi Jimson

    I know Weyand’s work is great and well referred to and accepted by a lot of people (even though it was done on a treadmill, but that’s another story…) but I do take some issue with essentially summising to say that the arms play little role at max velocity (“while arm movements are coordinated with torso and leg movements to achieve the energy transfers that minimize center of mass energy losses, they certainly do not control leg movements and have very little effect on the all-important ground reaction forces.”).

    Ask Pfaff or any sprint coach with some clues and you will see that what happens at the shoulder will affect what happens at the hip (pretty much directly). Therefore if the arm action (at the shoulder) is short/small then stride length will be compromised and stride frequency will increase (and ground reaction forces will change). As max velocity is a measure of these two factors then arm action must play a role in affecting max velocity.

    I don’t have a published paper to support it but I have seen it with 100′s of athletes so my research paper to support this is out in the field…

  • 2 thoughts.. I disagree with running arm mechanics for high school and under athletes not being a factor. Andrew Maclennan makes some valid points as well. For elite sprinters, who #1 are freaks and #2 are already set in their movement patterns(for the most part) I won’t disagree because I haven’t worked with nor have I extensively studied elite sprinters. With the younger athletes who haven’t been exposed to proper running mechanics can’t I stress enough how important both knee drive and arm drive relate. Once I get them from a F- to maybe a D those issues start to arise. I could talk about it for 3,000 words but I will say that they are definitely an issue with for athletes that have “brutal” mechanics and are struggling to find rhythm and suppleness.
    2- I used to think that complete extension of the back leg was necessary for complete acceleration and maximization of force production. A few years back after lightly studying elite sprinters, I couldn’t find a picture that showed a completely extended back leg when running at full speed. I changed my tune. Since I’m in a constant battle trying to keep my athletes at a “B” level with everything “athletic” I haven’t stressed that very fine aspect of sprinting. Wish that I wasn’t, but I’m constantly battling regression in technique after they return to their team sports and our training goes to in season maintenance in addition to survival from the abuse that their team sport coaches put them through.

    If I was a private track club coach and I owned the athletes year round, then that would be a different story.