21 Questions for JB Morin on the Topic of Speed

Several weeks ago I wrote a post reviewing a study on Christophe Lemiatre and what makes him so darn fast. The study was conducted by French professor JB Morin; an incredible researcher in the field of sprint biomechanics and speed development. JB was kind enough to sit down and answer 21 questions I threw at him. Understanding sprint biomechanics is not easy, and there are many different theories out there; some more evidence-based than others. Luckily we are learning more over time with excellent studies emerging on a monthly basis. This interview should help improve your understanding and confidence in sprint mechanics and the determinants of speed.

1. Hi JB, first off let me congratulate you for undertaking one of the most amazing studies I’ve ever read. You guys are coming out with some really great research! What is your background in sports and academics?

Thanks Bret. In academics I’m a Sports Science MSc, and I did a PhD thesis in Sports Science as well. In sports, I was a 400m hurdler. At age 22 I tried trail running for a while, but then I had knee-trouble, so I switched to mountain biking and now I’m a MTB and road cyclist. Interestingly, cycling research regarding mechanical effectiveness and the ratio of forces has been around for over 30 years, which gave me some of the ideas for my recent research.

2. Interesting! Now let’s get right to it. Based on your findings, what makes Lemaitre so damn fast?

From what we measured on the specialized treadmill (there could be other things we didn’t measure…maybe he has a huge amount of fast-fibers but we don’t know this yet), he has a better ability to orient the total force vector with a forward incline (he doesn’t have more total force production than his peers, or even specialists from other sports than athletics), and he has the ability to produce the highest horizontal force amongst his peers, and especially at faster velocities.

3. Can you please explain this in Laymen’s terms? Maybe you can provide an analogy?

At 6m/s on the treadmill, he’s producing more horizontal force than the National sprinters. Some of the non-specialist sprinters couldn’t produce any net horizontal force at that speed on that treadmill.

For the analogy, say that if he were pushing a big car, at the beginning he wouldn’t be that much better than his peers. But as the car built up speed, he’d keep getting better than his peers due to his ability to produce more horizontal force at higher velocities. Eventually he’d be the only person amongst his peers who could produce force as the car sped up sufficiently. This is what makes Lemaitre superior in this regard.

4. Brilliant analogy! I think that effectively sums it up. This study was performed using your special torque treadmill. How does the treadmill affect the force and power measurements compared to overground sprinting?

First, the treadmill allows for the measurement of force and power. It affects velocity in that the treadmill sprinting is slower than what’s seen overground (although these two velocities are very well correlated, as we’ve observed and recently reported in a recent study published in the same Journal). We’ve recently completed a study to determine how the forces are affected, but the values are within the range of what’s seen with overground force plates in terms of Newtons. For sure, the locomotion is indeed different since you’re tethered at the hips, you’re not moving forward, and you’re spinning the torque treadmill with your feet (which is not the same as overground running).

But the fastest sprinters overground were also the fastest sprinters on the treadmill, so the treadmill still allows for some interesting comparisons. And all of our studies with this treadmill share the same design, in which we compare the mechanics of subjects from various sprint levels on the same device.

5. Some experts might doubt the study you conducted based on the premise that the treadmill can’t possibly produce accurate data. Is there any merit to these folk’s concerts, and if you were to reproduce the study using a hypothetical 100m track of continuous force-plates, how do you think the results would differ?

The treadmill doesn’t allow for the same top speed velocities to be reached. For this reason, I won’t publish any data on “top speed” – in fact if I were a peer-reviewer for my own data I wouldn’t allow it to be published since the forces and velocities are different.

So we can’t answer the question about forces right now for top speed as we don’t know enough. But I think we’ll duplicate Weyand’s data – faster sprinters put more force into the ground. Part of our results from the “Lemaitre study” confirms this. But we’ll learn more since Weyand’s study only reported and discussed vertical forces; we’ll be able to look at all of the forces (vertical, braking, propulsive, and resultant).

Last, but not least, we are about to send for publication new and interesting results, this time obtained during real overground accelerated runs. Part of these results clearly confirms the treadmill ones, hopefully they will be published soon. If so, then the discussion will revolve around sprint biomechanics, rather than (or in addition to) treadmill vs. field measurements.

6. What’s the deal with braking forces, can we eliminate them completely during maximum speed running, and is some level of braking forces ideal to allow for more time for force development?

Until we have more clear data, my thought is that a certain amount of braking is necessary. At maximum velocity (which is constant speed), horizontal braking forces and propulsive forces cancel each other out (horizontal net ground reaction force is null at constant speed). You can have large braking and large propulsive forces, or you can have small braking forces and small propulsive forces. As long as they cancel each other out during max and constant speed then that speed is maintained and you won’t decelerate.

But I don’t think it’s wise to try to completely eliminate braking forces, especially during the acceleration phase of a sprint; I think there is an ideal amount of braking force needed to “stall” the neuromuscular system and allow for enough time for the build-up of sufficient force from the muscles. The latter resulting in greater amounts of propulsive force produced. There’s probably an optimal window, with too little or too much braking being less efficient. Furthermore, the center of mass “falls” down during the braking phase, and should this braking phase be too short, the overall orientation of the ground reaction force during the propulsive phase might be too vertically-oriented (and thus not enough horizontally-oriented).

I’m excited to very soon test this hypothesis with the data we collected during overground 40-m sprints. Last week, a paper published in the Journal of Strength and Conditioning Research (Kawamori et al.) revealed that the 10-m performance was positively correlated with the net horizontal impulse measured at the 8-m mark (this is mechanically logical), and that propulsive but not braking impulse was correlated to this performance. In addition, similar results were put forward in a classic paper by Joseph Hunter a few years ago, at the 16-m mark. This contradicts the idea I propose here, but my reasoning considers the entire acceleration phase, and although very interesting, Kawamori et al.’s data only focus on the first step and the step at 8m, in team sports players. Their study is also interesting in that neither vertical nor resultant impulses were correlated to 10-m sprint performance, only horizontal impulse was…As Hunter wrote: “the possibility of braking having some advantages could not be ruled out.” This is what we will test very soon with force data collected all over 40-m accelerations.

All this shows us that efficient sprint biomechanics research forces one to be humble since getting “ideal data”, i.e. overground measurements plus over several steps plus in top level athletes plus in competition conditions is a very tough work! Each study should therefore be considered as a little contribution bringing us one step closer to this “holy grail”.

7. What about vertical forces, should we try to maximize them during maximum speed running?

I agree with the hypotheses and conclusions of Weyand on that, I think you must be able to produce high vertical forces to run at high top speed, but you reach a limit. And as you speed up, you have shorter and shorter ground contact times. So you must be able to produce great vertical forces in exceedingly shorter times. But I don’t think that the fastest sprinter automatically produces the greatest maximum forces during sprinting; you want to produce sufficient vertical force rapidly in order to raise the COM but not too much as that would negatively impact speed. Because it has applications in many other sports than athletics only, I’m much more interested in the determinants of maximal acceleration rather than maximal speed.

8. And what about horizontal propulsive forces, these forces are most correlated with maximum speed, correct?

Again, we can’t say for certain; we don’t have the data yet for maximum speed. My guess would be yes. Net horizontal forces are probably more highly correlated with maximum sprint speed, and maybe more with maximum acceleration than vertical forces. But again, we don’t clearly know this yet.

9. Many sprint experts believe that since net horizontal force is zero at maximal speed (since braking forces are equal to propulsive forces), that they’re not critical and vertical force now becomes the more important factor since it helps get the sprinter off the ground quicker. What’s the problem with this line of thinking?

At top speed, you need to produce sufficient vertical force. You’re not accelerating anymore. However, since you can’t get rid of braking forces, you must have the ability to apply great propulsive forces while your leg is moving very fast to prevent deceleration. So if you want to improve top speed, you need to be able to produce greater horizontal propulsive forces. In fact, mechanically-speaking, there are two possibilities: either you are able (at top speed) to produce small amounts of horizontal braking impulse, and then the propulsive impulse needed to maintain a constant speed will be small, or you produce a larger braking impulse, and then…you’ll need a high propulsive impulse to “compensate” and maintain constant speed. If your propulsive impulse does not match your braking one, you’ll decelerate.

Thus, I really consider the acceleration phase and the top speed phase different from this point of view. Although I hypothesize (our data might soon prove me wrong…or not) that you need a certain amount of braking impulse during the acceleration, I think it should be reduced at top speed. At this moment, the distance your center of mass goes forward during the contact, and the net impulse you can produce, becomes critical. Furthermore, at this moment, I think that the backward push of the (almost totally extended) leg is crucial. And I also hypothesize that the role of hip extensors is underestimated. Although it appears from former studies that these muscles “shut down” around mid-contact, their action before contact (during the “pawing action”) and during the braking phase might be determinant.

10. Do you think that we can cue sprinters to affect their force production on the ground, or is the ground contact time too short to do so?

The idea is to be able to produce the most force while on the ground. I think you can indeed affect force production while on the ground through cueing, but the goal is not to try to stay on the ground for longer times just so the sprinter has more time to produce force. I’m not sure if cuing for pawing-back or popping off the ground rapidly would lead to better sprint times – the athletes probably figure out the optimal blend all on their own. I must say here that “pawing-back” the leg while in the air just before contact or while on the ground might be two different actions, maybe two different abilities, and maybe not equally efficient in leading to a high amount of horizontal impulse. This is another hypothesis I’d like to test.

11. Assuming that two elite sprinters weight the same and have identical ground-contact times and vertical forces, does the sprinter with the greater horizontal force per stride run faster?

My guess would be yes; he would accelerate more during the initial portions of the sprint and reach a higher top speed.

12. Usain Bolt and Christophe Lemaitre have the insane ability to continue accelerating through a substantial portion of the 100m sprint. What do you attribute this to?

If I remember correctly, if you take the speed-time curve of Bolt, he accelerates up to something like 80m. For Lemaitre it’s more like 65m, and he does indeed decelerate. Everyone decelerates, but he decelerates less than his competitors. Bolt and LeMaitre have excellent “endurance” for net horizontal force production. Each of them is amazing at the 200m sprint. If Bolt wanted to, he could probably break the 400m record. They have an uncanny ability to transmit forces, and I bet they have great foot/ankle properties that allow for optimal transfer of power from the glutes and hamstrings down into the ground. I like the approach of “producing AND transmitting force effectively to the supporting ground”. Sprint training should focus on both.

13. What makes sprinters slow down? As they fatigue, what happens to their forces and power output?

I don’t know. Until we get sound measurements I can’t say. I’d guess that you’re getting neuromuscular fatigue which lowers your vertical and propulsive forces. In addition, the neuromuscular fatigue might reduce the ability of the feet to transmit force into the ground, since the foot/ankle deforms more at the end of the sprint compared to the beginning of the sprint. But until we have sound measurements, these are just hypotheses.

14. What muscles do you feel are most important for speed? Is every muscle in the body equally valuable or are some more important than others?

Speed is vague. You need knee extensors and you need plantarflexors. But I really think you also need powerful hip extensors to accelerate. At full speed, you need stiff ankles and powerful leg extensors. You need it all! Remember that at top speed your lower limb touches the ground in an almost-fully-extended position. Anatomically, the muscle groups generating a backward motion of the limb are rather hip extensors than knee extensors (the knee is almost fully extended). That said, you need it not to “deform” too much, same for the ankle. It is an easy answer to say “everything is necessary”, but I think that as speed increases during a typical acceleration, and at top speed, producing the force, and transmitting it to the ground predominantly relies on different muscle groups. Especially, as speed comes close to maximum, the ability of ankle and knee “stabilizers” to allow these joints not to deform too much during the huge impacts at each step might be a prerequisite for an efficient propulsive action of hip extensors…and a high horizontal impulse production.

15. Now let’s talk applications to training. Do we just need powerful hips or is there more to the equation?

As I just mentioned, you need a strong motor in the hips (and in the knees and ankles, for the early phase of acceleration, from a crouched position). But you also need stiff ankles (and knees as speed increases) to transmit the force with effectiveness. You can have a superior motor (glutes and hamstrings, or even quads) but if you have a flat tire (weak ankles or knees that deform too much at the ground), you won’t move very fast.

16. I know you’re interesting in cycling as well. Does this same principle apply to cycling?

Producing and transmitting force in cycling is paramount. If you have big glutes / quads / calves but your ankle stabilizers are tired, your heel goes down, your foot goes up, and your push is wasted. When I train cyclists, I have them do exercises to work their ankle strength and endurance (just as I would do with basketball players) and they look at me like I’m insane. They say, “But we’re cyclists, why are you giving us track exercises?” I have to educate them about the importance of the ankles.

17. What are some drills and exercises that you recommend for sprinters?

Exercises that put the body at an incline such as sled work, towing, elastic bands, and incline sprinting are great.

Speed, speed, speed is critical. You don’t need to obsess with weight; you need to think “explosion.” You need force, but you need to produce force very quickly. Don’t forget about velocity! Whatever the load you push or draw, focus on doing it as fast as possible.

I also like to train the ankles for endurance. For example, take a 20lb barbell on the shoulders and jump from right foot to left foot while on the balls of your feet, or jump with a high frequency on one foot only for 20 reps, then on the other, and so on, or from right to left over a lane line, etc…. Do this for 3 minutes – they’ll burn like crazy. This will build tremendous ankle endurance. In addition, these muscles are involved in our overall balance while standing, so they have a high endurance, don’t hesitate to “burn” them until you can not stand on your feet, they recover very fast.

18. Are there any drills and exercises that you feel are overrated for sprinters?

Everything is good, but in the right amounts. Deep squats are good. But too much of them and with too much weight is not ideal. Coaches usually employ excellent exercises but the dosages are not always ideal. In general, never stray too far from velocity. But I have to admit, many coaches over-emphasize the squat. For many sports such as soccer, their quads are already strong and they sometimes need to focus more so on their posterior chain, for both performance and injury prevention reasons…

19. Are there any cues that the French sprint coaches are giving to the French sprinters that differ from the norm?

For what I’m aware of, there is no consensus in France and every coach has his own view and practice. For instance, some of them are not too concerned with maximum strength. When we say, “strength training,” all too often people assume “heavy strength training.” But some of the guys in France use lighter loads and work more on the velocity side of things, with very specific strength exercises. Although I don’t know how people train all over the world, I think we also do more work for the foot/ankle complex.

In France, overly muscular athletes have often been perceived as anabolic steroids users, and it is possible that this has refrained coaches from using heavy strength training too much. France has a huge anti-doping stance, and ironically this might have benefited France because we’ve figured out ways to improve our sprinters by improving their power through velocity and/or force application technique, and not so much through force and bigger muscles.

20. Any insight as to how Christophe Lemaitre trains?

Lemaitre has an outstanding ability to transmit the force onto the ground, and I think he is also very “endurant” in doing so. This is his strength. But I feel he could benefit from improving his ability to produce force. He has excellent sprint endurance too. I’m curious to see if he’ll improve his 100m time this year, but I think he’ll definitely improve upon his 200m time. It’s common knowledge here in France that Lemaitre never did any serious strength training prior to breaking the 100m barrier. Maybe a couple sessions per week for a couple months, but never anything very intense or drawn-out. In a newspaper article here in France, his coach stated that Lemaitre’s maximum deep squat was 240 lbs, which many track coaches would believe to be incredibly low. These days he’s doing a little more maximum strength work, but I don’t expect it to have too much of an impact right off the bat as it takes time for training gains to come to fruition.

21. Thank you very much for your time JB! It is much appreciated. Last question: Do you have any exciting research in the woodworks?

We certainly do. We’re doing some testing on acceleration using overground force plates to see if we get the same measurements that we did in the treadmill study. So in essence we’ll be critiquing our own study on the treadmill by comparing to overground sprinting.

We’ll also be looking at sprint speeds, isokinetic torques for the quadriceps (knee extension), hamstrings (both knee flexion and hip extension), glutes (hip extension) and foot motion during the sprint cycle to see what correlates best. Data have now been collected, and we’ll discuss the role of hip extensors in the “pawing” action, both in the air and then during contact, and in turn in the horizontal force production during accelerated runs. We synchronized EMG, 2D video and treadmill GRF measurements, to try and see what muscle groups are the most involved and the most efficient in generating horizontal force production.


  • Tom says:

    Deep squat 240lb. That very interesting. Will probably take some of the strength is everything proponents by suprise

    • Bret says:

      Yep; that’s what I would have predicted to be honest. I bet that’s more than Usain Bolt can deep squat…

    • RickP says:

      I also found that very interesting. However, 240 pounds for a deep squat (AKA butt-to-ground or ATG squart) sounds excellent. Sure, that is not impressive for a legs to parallel squat. Am I wrong?

  • Tom says:

    Deep squat 240lb. Thats very interesting. Will probably take some of the strength is everything proponents by suprise

  • OKtav says:

    Thanks again BRET!

  • OKtav says:

    …Well because charging with squats is not may be the key. Is not the only coach from “the old school” who does not really give “more than 5 pennies” on the workout with weights… and I think they are not wrong.

  • OKtav says:

    Well I have to reformulate. Do not have to be a savant to say that strength is needed in all compartments of the triple extension chain. I think that Dr. Balthazar didn’t assume any risk during this chat… As I’m going to do in the next few sentences. What for deep-squats with a heavy bar? Oh I’ve forgot the glutes :). Nothing in a deep squat does look like what is happening during a 100m race – angles are not the same, the pattern is different…and not even one word about the superior part of the body. Next time I’ll ask the doctor to advice coaches to tie sprinters arms, who knows may be they will save some calories and thus being ables to maintain longer their acceleration phase. As about a great number of fast fibers in LM’s body – wow, this might be the reason why he has always the slowest reaction-times and worst departures than the rest of finalist. I’ll ask again, what for deep squats with heavy bars!? I’m trying hard for few years to find out something from people involved in sprint’s biomechanic…never got an answer! Actually I think they do not have to much to say. Thank you BRET for the efforts.

    • Bret says:

      Oktav, you’re preaching to the choir about deep squats. I think the quads are overrated for sprinting. It’s all about hamstrings and glutes to me.

      Now, to argue with you a bit, I don’t feel that the upper body is very important for sprinting. Sure you could tie the arms behind the back and you’d be very slow, but that doesn’t mean that they’re the limiters of speed. For example, if you increase one’s bench press and chin up strength by 30% you probably won’t see much improvement in speed. The arms are not producing very much torque in terms of Newtons when sprinting; they contribute a bit to vertical but not to horizontal, and they’re critical for transferring energy, but they don’t limit speed IMO.

      And I would suspect that LM’s physiology is superior in terms of muscle fibers, but I think his leverages for hip extension is probably superior too.

      Thanks for jotting down your thoughts! – BC

      • RickP says:

        Can you explain what you mean by “leverages for hip extension”? And what does coach JB Morin mean when he says, “you want to produce sufficient vertical force rapidly in order to raise the COM…”? What is COM? Thanks.

        • Eric says:

          RickP… Better leverage in terms of expression of muscle force through the body’s main hip extensors, especially the glutes, but also the hamstrings… COM = center of mass…

          • Bret says:

            I’m just guessing that his moment arms for hip extension at ROMs associated with ground contact are better than his competitors. I’ve never seen this researched, but let’s say his glute max and hamstrings originated and inserted in a manner that gave him a 20% advantage in terms of hip extension leverages in more extended ranges of hip extension, this would be a HUGE advantage.

            Just a theory, I could be WAY off base.

      • OKtav says:

        Hi Bret,
        I have huge problems with my English and probably I didn’t transmit what I’ve wanted to. I’m not the fan of deep squats with heavy bars in sprinter training…I’m totally at the opposite side of what some people are doing – weights (for excessive strength). I do not say that all that has to be banned. I’d use gym workouts in very specific conditions and very carefully (even if daily) – short sessions, high intensity, and never “heavy charges”. I never said that quads are the key. Actually I didn’t say anything;I’ve just noticed that the doctor didn’t enlight me. Well… actually I’ve said something – triple extension (as Mr. Morin did it too, but in a different way). First off all in my opinion the “strength” is not at all the key. But as participant component, I’d consider it at all the levels – glutes, quads, hamstring, ankle and toes flexors 🙂

  • Mat Herold says:

    Bret and JB, great interview. It is interesting to hear the lack of emphasis on weight training once again when it comes to speed. I find that in most cases as strength goes up so does improvement in acceleration. Top speed, different ball game.

    • Bret says:

      This has been my experience too, but I don’t train elite sprinters. With typical male athletes, you emphasize heavy strength training and they drop .2s off their 40yd in 2 months! The same can’t be said of course for the elite. So I’d agree that acceleration improves with hst but I’d assume that top speed would too. I suppose I’ve never seen a study with an elite population of sprinters that showed the effects of a hst intervention on acceleration and max speed. Thanks Mat!

  • Eric says:

    Great article Bret! Thanks for setting that up and sharing. Not sure if you’ve heard of Barry Ross but, he’s been making very good use of Weyand’s data for quite some time now in designing his sprint training approach. Increase force production in the gym (he’s preferred a concentric-only deadlift over any other exercise; won’t get into the details of it here as to the “whys” but, suffice to say it has to do with efficent training in terms of time spent in the gym AND limiting disruptions in sprint training and of what is ultimately the main goal: running fast) coupled with skill training on the track/field. I’ve used a similar approach myself with young athletes, and to great success. If you can increase strength in the gym and then work on reducing the rate of deceleration from top speed on the track, I think this can be a very sound approach… I think it’s all a game of balance. Too much strength isn’t necessarily correlated with reduced speed on the track as much as it is spending too much time in the gym relative to the track; each athlete as inherent adaptive capacities/energy from which he or she can draw upon. Bringing both speed and strength up at the same time, without sacrificing one over the other, and according to the individual’s given characteristics, is what makes this whole thing “art” just as much as “science” 🙂

    • Bret says:

      I’ve seen Ross’s stuff and I like a lot of it. But some of it makes me wonder. For example, I agree that the deadlift is the best lift if you could only choose one, but he does so on the premise that it activates the most total-body motor units (correct me if I’m wrong). If this is his premise, then I believe he’s leaving room on the table as the hip thrust activates more glute fibers, and muscles should be trained in multiple functions (knee flexors), plantarflexors should be trained, etc. This is just my opinion…I’m sure his system works very well but as a coach I wouldn’t be comfortable with it. I do like his emphasis on time efficiency in the weightroom though. Agree it’s a game of balance and the trick is to bring up strength while maximizing power and coordinating it into the skill (sprinting).

      • Patrick O'Flaherty says:


        In your muscle activation tests using EMG, what % of the gluteus maximus was activated with parallel squats, deadlifts and hip thrusts, etc.?

        Interestingly according to the research data below, full depth squats elicited a relative 26% more (7.4% absolute) glute activation than parallel squats but still only effected just over 1/3 of the fibers.

        Squat Depth Abstract
        The purpose of this study was to measure the relative contributions of 4 hip and thigh muscles while performing squats at 3 depths. Ten experienced lifters performed randomized trials of squats at partial, parallel, and full depths, using 100-125% of body weight as resistance. Electromyographic (EMG) surface electrodes were placed on the vastus medialis (VMO), the vastus lateralis, (VL), the biceps femoris (BF), and the gluteus maximus (GM). EMG data were quantified by integration and expressed as a percentage of the total electrical activity of the 4 muscles. Analysis of variance (ANOVA) and Tukey post hoc tests indicated a significant difference (p < 0.001*, p = 0.056**) in the relative contribution of the GM during the concentric phases among the partial- (16.9%*), parallel- (28.0%**), and full-depth (35.4%*) squats. There were no significant differences between the relative contributions of the BF, the VMO, and the VL at different squatting depths during this phase. The results suggest that the GM, rather than the BF, the VMO, or the VL, becomes more active in concentric contraction as squat depth increases.

        • Bret says:

          Patrick click on this to see the chart: http://www.t-nation.com/testosterone-magazine-623#inside-the-muscles

          The abstract you posted was on the Caterisano study and it used the same load for all depths rather than relative loads. But hip thrusts give highest activation, followed by deadlifts, followed by squats.

          • Patrick O'Flaherty says:


            Thanks for the link. However there’s got to be more to this than EMG being the most valid measure? For example, the Body Weight Russian Leg Curl has got to be the most difficult double-leg lower body exercise EVER with no assistance from a reverse band or dropping into a plyo-push-off with the arms. Plus the EMG reading in the Biceps Femoris (Hamstring) was ranked only mediocre. It would be very hard to accept that one could build a more powerful set of hamstrings doing only weighted bird dogs (Peak EMG 173) versus BW Russian Leg Curls (Peak EMG 94)!

          • Bret says:

            Hi Patrick, I commend you on your critical thinking. I agree that RLC’s are one of the most difficult exercises. I also agree that there’s much more to analyzing exercise efficiency than just examining EMG. Ideally you’d see the EMG throughout the whole lift to see how it corresponds with different ROMs. But you really need to understand other things, such as length-tension relationships, activation-angle curves, and moment arm curves. These are difficult to explain. But an RLC is going to have lower activation simply because the hammies aren’t at an advantageous length while lowering, and the hammies are mostly acting as knee flexors (the hip ext component is not that great as it just involves holding the torso upright). For this reason the weighted bird dog does outperform it. And the weighted bird dog is actually pretty difficult for the hammies at that peak position (fully extended). The fact that you asked this question shows that you’re a critical thinker and are seeking further understanding, so I urge you to continue your learning as you’re a very smart dude! In fact your question reminds me of something that I’d think up and then spend hours upon hours trying to figure out the answer. Cheers! BC

  • Aaron says:

    Great article Bret! How would you train for ankle mobility, yet for maximal stiffness? Isn’t stiffness created by a “tight” muscle that limits movement? Or would it simply be the reactive ability of the muscle to limit the mobility in a joint at ground contact?

    Thanks again!

    • Eric says:

      Stiffness is more a neuromuscular property, and refers to a muscle, when rapidly stretched, having the nervous system trigger a rapid, reactive contraction. Stiffness is dependent on neural characteristics, but also strength development. Stiffness does not mean inflexibility and tightness. Basically, you should think of stiffness as the ability to be non-compliant under high velocity loads. Think golf ball vs tennis ball. Non-compliance means less force being dissipated and thus a higher force production.

      • Bret says:

        Yep; muscle activation modulates stiffness (but passive stiffness can be increased as well by strengthening connective tissue). In this case you want stable ankles so the eccentric ankle/foot/toe muscles store energy and then return the energy later in ground contact phase so you’re essentially converting some vertical energy to propulsive energy. Just my two cents…I could be wrong.

  • Rob Panariello says:

    Very nice interview BC. To add to the comments already posted the exercise selection for our athletes should be based upon an evaluation (i.e. noted deficits and the type of strength(s)/physical qualities required by the athlete) for enhancement of their athletic performance, and specific to this discussion, speed. What also should be noted based on the athlete’s sport, position of play, etc… is the type of “speed” required (determined in the evaluation as well) i.e. starting abilities, acceleration capabilities, maximum speed, maximum speed endurance, etc… as this will also have a correlation to the exercise selection and program design of the athlete. Some athletes may never achieve maximal velocities levels in their particular sport of participation.

    After a work capacity is established, specific exercise(s) selection, along with an appropriate training program design of exercise volume (i.e. “Coaches usually employ excellent exercises but the dosages are not always ideal”) and intensity is incorporated in the training program. The exercise(s) selected should be viewed in regard to all of the physical contributions the exercise may provide, as in this discussion the squat has been mentioned. If performed correctly, in addition to lower extremity strength enhancement, the athlete will also improve hip and ankle mobility, muscle and joint stiffness (both mentioned in this thread), CORE strength from bar support upon the shoulders, etc… If further hamstring and glute strength are an emphasis, a safe adjustment may be incorporated during squat exercise performance to further emphasize these muscle groups (I have known a few powerlifters with larger hamstring vs. quadriceps muscle groups) or perhaps a different exercise may be better suited for the athlete.

    A great point was brought out by Eric about spending time in the gym focusing on strength development as once sufficient strength is developed for the physical quality at hand (i.e. how much strength is enough?) and the “deficit” found at the time of the athlete’s evaluation has been resolved, perhaps better time is spent on the enhancement of a different physical quality or different environment i.e. track vs. weightroom to train this particular new physical quality. This is not to insinuate that more than one physical quality may not be trained simultaneously; however, emphasis should only be placed upon a specific physical quality of emphasis and only for a specific period of time to ensure the optimal development of the specific selected physical quality to be trained.

    Since “speed” is at the end of the continuum of the various physical qualities of development, i.e. Strength -> Explosive Strength -> Elastic/Reactive Strength -> Speed, one may view the physical quality of speed as the most important physical quality as speed more often than not encompasses all of the other physical qualities which is necessary to achieve optimal maximal speed performance.

    What to utilize, when to utilize it, how to utilize it, etc…. is the ability to see the big picture. This is the art of coaching.

    Just my opinion

    Rob Panariello

    • Eric says:

      Nice to see you here Rob! Don’t know if you’ll recall but, we corresponded some time ago regarding an ACL/MCL/LCL tear with meniscal tears, initially through an article you had written on Jimson’s blog… Great comment too, of course 🙂

    • Bret says:

      This is an area that I feel needs more research…a battery to determine strengths or weaknesses in particular areas. For example, most coaches wouldn’t know how to assess reactive strength, speed strength, etc. and don’t have optimal technology to measure it. And what are normal ranges so we know when someone has a particular imbalance. I have my ideas, but it would be nice to have good standards. I know the All-Blacks in NZ are big on this – they’re well aware of all of their players’ max strength, high-load speed strength, low-load speed strength, elastic/reactive strength, isometric strength at various positions, etc. However, they’re biased in the vertical plane IMO and they need appropriate assessments in other planes/directions. I believe they’re working to improve this at the moment. But all teams should follow they’re lead and develop standards to determine weaknesses and strengths in these areas. This way players can become more well-rounded.

      And I agree…once certain speed athletes reach certain numbers, it may be more fruitful to focus on increasing velocity at certain submaximal loads.

      Just my two cents…great thoughts as usual!

  • Bret, Great interview, thanks for posting this excellent blog on the latest Sprint research!
    I do think that the arms, however, are more important for sprinting being a sprinter myself. Although I am far from being elite, I do feel that the shoulder and arm action is critical to helping the body deliver the proper forces in both the vertical and horizontal directions upon touchdown.

    I chuckled at the part about the ankles being like flat tires.. that is totally me! I feel like I have pretty good hip extension torque and power, but I have no idea how to teach my feet and ankles/calves how to handle these forces!

    I look forward to see what further research this guy comes up with; great stuff!

    • Bret says:

      Hi Keats, I do agree that the arms are important for these mechanisms, but I’m not sure if they’re “big-rocks” for training sprinters. But I confess to watching certain college football buys run the 40yd and their upper bodies are so powerful it could indeed be aiding in their speed. Some of them have what would be deemed “horrible” mechanics and are swaying all over but are running 4.4’s left and right. So you could indeed be right.

      You’re right – you do have flat tires haha! JB will undoubtedly continue to come out with excellent stuff as he’s a top-notch researcher.

  • Tasher says:

    Thanks Bret! As usual, the information you share with us is stellar and I can’t wait to see the results now that I’m tweaking the current exercise regimen. I’m just wondering how I can develop fatigue resistance for the neuromuscular system with minimizing deceleration in mind? Or will there be some “carry over” from addressing ankle endurance like JB said?

    Please interview him again in the near future. His focus on the acceleration side is exciting and the results will be fascinating to consider, especially for a soccer coach. Players barely reach top speed with the greater majority of sprints less than 20m, so acceleration is key!

    Aaron, there are some great articles that suggest the use of plyometrics to achieve greater levels of ankle stiffness.

    • Bret says:

      Glad you liked the interview Tasher! Yes ankle endurance should theoretically decrease fatigue/deceleration, and I feel that increasing hip power endurance possibly via slightly higher-rep explosive hip extension exercises could be valuable too. As you can see I have a bunch of untested theories and I wish I trained elite sprinters so I could experiment. I’m sure I’d learn a ton and would end up keeping certain methods and abandoning others.

  • KG says:

    This was cool interview. Thanks Bret! I have always been fascinated with subject, especially because there still seems to be some mystery to it. Ever since I was younger I have never met someone faster and I have been always curious why that is… Even through recent years of an arthritic knee and leg injuries making my legs absolute twigs, I have still been able to stay faster than my peers. I am anxious to here more about the theory of having more fast twitch fibers that the researcher mentioned. I am really not trying to sound conceited here, but probably will come off that way lol.

    • Bret says:

      KG, definitely not conceited. I suspect you have high fast twitch fibers and possibly other things (lots of research showing sprinters tend to have certain characteristics – it’s been a while so I’m probably going to butcher some of these, but if I recall correctly these include: longer fasicles, lower pennation angles, longer toe extensor moment arms, lower lower-limb mass, the ACTN-3 gene, stiffer tendons in certain muscles such as the Achilles, etc.). And I wonder about hip extension moment arms too as mentioned above. Could be way off on that one…just a theory. But I’m sure if a lab analyzed you then you’d realize why you tend to be faster than others even though you don’t possess a lot of muscle. I’m sure your nervous system functions much better than that of others too in regards to speed-related mechanisms.

      • KG says:

        Thanks for the reply Bret. Very interesting stuff. I have finally been able to gain some strength back in my legs thanks to reading your stuff as well some help from Cressey Performance. I’m up to 325 on the floor barbell hip thrusters now! Thank for all the helpful tips.

  • Rob Panariello says:

    I agree with you Keats. The arms are important in re: to running velocity. I always remember an example taught to me by Al Vermeil years ago. Try walking at a normal pace with long extended arms. Now shorten your arms (as in a sprinters arm position) and move your arms rapidly as you start walking once again. What happens to your walking stride rate? Now with this said, the “horses” come from the hips and lower extremities.

  • Sven says:

    Bret, thank you for your explanations concerning hamstring activation during the Russian leg curl and weighted bird dog exercises. I wanted to ask you, how do you explain the high activation levels elicited by the gliding leg curl exercise, where the hamstrings act as both knee flexors and hip extensors, which, I would have thought, means that they aren’t at an advantageous length (please correct me if I’m wrong on this).

  • Sven says:

    Bret, any reason why you seem to never answer my questions?

    • Bret says:

      Sven, it is just my theory…but I’ve notice that straight leg hip ext exercises receive much higher EMG activation than leg curls, so I conclude that they activate better at longer muscle lengths. The gliding leg curl spends the first half of the movement at longer (stretched) lengths before moving into knee flexion.

      • Sven says:

        Thank you! Yes, I understand. What was perplexing to me is thaWhat would be the benefits of performing the gliding leg curls on top of the hanging straight leg bridge? According to your EMG tests, the former would activate more adductor longis…

        • Bret says:

          The gliding leg curl involves a straight leg bridge, followed by a leg curl…it’s a long-duration exercise as first the hips raise and then the legs curl the body forward. See my youtube videos.

          • Sven says:

            Thank you 🙂 Yes, I have seen two videos on it and regularly use it. And the hanging straight leg bridge, as well. Single-leg. They’re great. Thank you very much for these two ideas, and for all the rest. I hope it is a good idea to perform both?

          • Bret says:

            Yes, but you must keep the hips high; don’t let them drop. Single leg is too hard for most.

  • Sven says:

    Sorry, I was trying to write:
    what was perplexing to me is that the knee flexion movement takes place when the hmastrings are already significantly shortened from the hip extension…

  • Sean says:

    Hey Bret,
    Thanks for the interview, it helped clarify some ideas I have on training for speed.
    What books/ resources would reccomend to learn more about sprinting/ trainin/ biomechanics etc?

  • Andy... says:

    “They (Lemaitre/Bolt) have an uncanny ability to transmit forces, and I bet they have GREAT foot/ankle properties that allow for optimal transfer of power from the glutes and hamstrings down into the ground.”

    So when we relate that back to the recent Taylor/Beneke study…

    “Even though Bolt achieved the greatest velocity (12.3 m.s – 1) over the 60-80 m split compared to his competitors, his estimated vertical stiffness (355.8 kN.m – 1) and leg stiffness (21.0 kN.m – 1) were SIGNIFICANTLY lower than his competitors.”

    So potentially Lemaitre has the exact same idea as Bolt with regards to leg stiffness, one major difference is that Bolt’s got far more oomph in the glutes/hammies.

  • Andy... says:

    Bret says, “All this posterior praise is richly deserved. The hamstrings:

    Decelerate: HIP FLEXION and knee extension.”

    Bret, is that a typo, ‘Decelerate’?.

    • Andy... says:

      Can anyone else chime in here too what is being implied?, or is it just me that finds it kind of important, lol.

      Obviously anything that decelerates hip flexion is a negative in sprinting?, particulary during that acceleration phase (Ben Johnson ’88 final).

      Sorry for the thick question, but is the IMPLICATION that doing too much hamstring work severely hampers the power/speed of hip flexion?.

      • Andy... says:

        (Blazevich, Anthony J.; Jenkins, David G., 1998).


        The regression analysis indicated that hip flexor strength at all test velocities was a better predictor of sprint running performance than hip extensor strength.

        (C) 1998 National Strength and Conditioning Association.

        • Bret says:

          Andy, do you think you’re cherry-picking here?

          • Andy... says:

            Well no, I want to be the sprinter I can be?. Can anybody answer my questions please?, then it won’t sound as much like I’m cherry picking. The main one being… If the hamstrings decelerate hip flexion, does that mean placing too much emphasis on them hampers hip flexor (flexion) speed velocity?, in other words, do they decelerate the swing speed of the upper thigh?, ala the (Blazevich, Anthony J.; Jenkins, David G., 1998) study.

            If so, how can “All this posterior praise be richly deserved”?.

  • steve crocker says:

    Wow. This is making me think more than I ever have on the whole topic of sprinting. I have often been baffled as to why some fellow masters sprinters have been able to run me down when I was physically stronger in virtually every exercise ( superficially measured) and trained harder.
    If anything these articles are clueing me as to how much I don’t know.
    Very humbling. Thanks again.
    With work retirement just happening and no debilitating wear and tear to cope with, I hope to work out how to apply forces more efficiently and run fast at 60.

  • This post has a lot of important things to be careful about. I’m a athlete(18 YO) from previous year and my best was 11.33s with a bullshit sprint track training of about 5 months(I wasn’t going to gym). So I realized that how much bad my coach is. (There was a problem with my hip flexor extensibility. So when I was lifting my knee I wasn’t able to get too much force. Shortly, got a hip mobility problem.)

    This year I mostly focused on strength and intensity work but almost no GPP(endurance, work capacity) work. I improved my squat from 300lbs to 370lbs and deadlift about 80lbs. And I increased my box squat from 115cm to 135cm. But my 100m time wasn’t going that well. So after I runned 11.84s in national meeting I finished my season and after rest some started to work with some endurance and work capacity training. There is about 2.5 months of training with high volume, low intensity. And I reduced my time from 11.84s to under 11.5s with no high intensity sprints at all(My RDL dropped about 40lbs, there wasn’t 2 months weight training).

    So the horizontal force is the key. One of the best thing see this from video analysis is to look at the total angle between two femurs. My hip thrust is about 480lbs. I know It’s not great but It’s better than the sprinters those are in my city. But having strong glutes and hammys is not answer. Using them is the key. Because even with my that hip thrust, others getting better hip extension than me. So, be careful about mobility and coordination(biomechanics).

    Also, sprinting is a power event but not like weightlifting. Getting stronger, more powerful doesn’t make you faster in track. So, there is something more about sprinting that weighlifting type sports. All of the parts of sprinting must be training because all of the phases are different.

    In my opinion, as biomechanically It’s happenining in the hip. Bret probably know more about this than any other person.

    Thanks to JB Morin and Bret.. Keep it up!

    • Bret says:

      Totally agree Yusuf. Using them during such rapid actions is key. Strength (max force) is important but is very overestimated by S&C professionals. A good program will blend all the needed components together so that the proper technique, mobility, strength, power, and speed endurance is there. Thanks for the anecdote!

  • Ralph says:

    Groundbreaking research by Morin et al. – thanks for sharing and congrats on your excellent site, Bret!

    Which exercises/drills do you recommend to improve maximum sprinting speed vs. acceleration (in light of increased importance of horizontal force/power and velocity-oriented F-V profiles? Is there any particular research/advice you can point me to? Thanks in advance.

    • Bret says:

      Plenty of sprinting Ralph, and also bounding, hip thrusts, Nordic ham curls, and back extensions. But these methods need to be shown to be effective (and more effective than traditional training) in longitudinal training studies. Until then, it’s just theory. There is no research on this at the moment.

      • Ralph says:

        Thanks Bret! I guess boundings should focus on minimizing ground contact time, rather than length/height? What do you think is most crucial to improve high-speed acceleration/top speed? In my opinion, RFD becomes the more determining the more ground contact times decrease. Plyometrics should be appropriate to train RFD. But how do you rate ballistics (e.g. low-load jump squats) in this regard? Some research indicates that RFD improvement through ballistics is even superior to plyos.
        You’re right – this “new” approach needs to show its effectiveness. Though, fortunately there is more supporting research on this, e.g. from Brughelli et al. For me, Christophe Lemaitre acts as an elite-example of a lean, velocity-oriented (vs. force-oriented) sprinter. Interestingly, a new meta-analysis seems to support the traditional approach: https://twitter.com/laurentbseitz/status/492471999499751424

  • Tom says:

    I was reading some of JB Morin’s sprint acceleration papers for some biomechanics coursework, stumbled upon this. Really rate this interview, good questions and good answers. Squats are definitely overrated for sprinting.

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