Read the Article here, and discuss it below.
ELITETRACK Founder
Newtonian Model of an Elite Sprinter: How Much Force do Athletes Need to Produce Each Step to be World Class?
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Keymaster -
Keymaster
Just wanted to point out that this article was written by board member Jeremy Richmond.
ELITETRACK Founder
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Participant
A couple of glaring weaknesses, especially if this model is to find an application either you need to assess superiority over current models or make refinements to current models and I didn’t find this to be true. It’s not that I could have done better, I have been trying for 3 or 4 years now to do what you just did and obviously I haven’t come close. I am still collecting papers and having trouble expressing the thoughts into written words.
You have 3 Mero and Komi references which are not balanced by the majority of research papers in existence regarding Newtonian physics aka Classical Mechanics and sprinting.
No James Hay references, Hay has a great review article discussing step length and stride rate of acceleration. You did reference an article of his understudies I believe.
No Blickhahn, Farley, Hegland, Taylor, or McMahon references, you did reference Weyand, but even Weyand’s work has plenty of background from the aforementioned authors of what I would term as necessary and classical references concerning classical mechanics, modeling, and sprinting. If you are going to reference Weyand then you need to reference one of these giants as they are the link from Cavagna and Alexander to Weyand.
In no way does this invalidate your article, but I believe to apply your model to sprinting you need to show greater account of the existing models which describe movement already and not just the originators of said of models.
lastly, application of the model to other data, Coh’s subject and Johnson’s 1987 WR or Greene’s 1999 WR is fine, but apply the model to other existing sets of data and provide how well the model fits and if it doesn’t fit some data from differing data sets where does it fall apart. I would have tried to fit it to as much data as humanly possible.
Overall its a great paper and provides a ton of insight, the Di Prampero and Hunter references are something I liked seeing.
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Participant
A couple of glaring weaknesses, especially if this model is to find an application either you need to assess superiority over current models or make refinements to current models and I didn’t find this to be true. It’s not that I could have done better, I have been trying for 3 or 4 years now to do what you just did and obviously I haven’t come close. I am still collecting papers and having trouble expressing the thoughts into written words.
You have 3 Mero and Komi references which are not balanced by the majority of research papers in existence regarding Newtonian physics aka Classical Mechanics and sprinting.
No James Hay references, Hay has a great review article discussing step length and stride rate of acceleration. You did reference an article of his understudies I believe.
No Blickhahn, Farley, Hegland, Taylor, or McMahon references, you did reference Weyand, but even Weyand’s work has plenty of background from the aforementioned authors of what I would term as necessary and classical references concerning classical mechanics, modeling, and sprinting. If you are going to reference Weyand then you need to reference one of these giants as they are the link from Cavagna and Alexander to Weyand.
In no way does this invalidate your article, but I believe to apply your model to sprinting you need to show greater account of the existing models which describe movement already and not just the originators of said of models.
lastly, application of the model to other data, Coh’s subject and Johnson’s 1987 WR or Greene’s 1999 WR is fine, but apply the model to other existing sets of data and provide how well the model fits and if it doesn’t fit some data from differing data sets where does it fall apart. I would have tried to fit it to as much data as humanly possible.
Overall its a great paper and provides a ton of insight, the Di Prampero and Hunter references are something I liked seeing.
Firstly, the article is not intended to be superior to other models because I haven’t yet found a model that attempts to convey how much resistance to train against when training for sprinting. Whilst various researchers show the force produced during the start, first step, second step, 14-16m mark and top speed of approx 9.5 m/s I felt the need to know how much force is produced during the entire acceleration. In this way, training methods could be modified or developed in order to be more velocity or movement specific. For example, when nearing maximum speed only between 10 and 15 kg of horizontal force needs to be produced although it must be realised at great angular velocity. Therefore, when doing an exercise such as cable-kickbacks one only needs to lift this amount and move the leg at a practical speed. Strength training with this specificity would allow an adaptation in the prime moving muscles that could be progressed over time.
This model is described as Newtonian simply because we use Newton’s equations of motion. It is intended to be simple enough to be able to supplement a coaches plan. The classical work of researchers such as Blickhan, Farley, McMahon (spring mass) or research work on energy systems are difficult to relate to training methods for most coaches. The tools readily available to coaches are resistance training, plyometrics, ballistic jump squats, Olympic lifts, hill running etc. for which I’m hopeful the Newtonian model can provide some guidelines (on horizontal force). The work of the respected aforementioned researchers on the contribution of elastic recoil of muscle-tendon complexes is appreciated in the calculation of forces produced per stride as the forces are as a result of such mechanisms. Instead of focusing on internal mechanisms that are rather complex, the sprinter just needs to know that they should produce a horizontal force of the order of 79 kg from a split stance that would replicate the stance in a starting block, in 300 milliseconds. If they can’t then why not? A coaching strategy could be to focus on speed of movement if the sprinter can lift this load already, and a reasonable guide is to be able to take a first step length of 1.23 metres as a result. From there the step length should increase gradually as this could make efficient use of fuel sources within the muscle. The Newtonian model is a guide, a point of reference to help coaches who I’m sure would not take the information as the gold standard and take into account the various individual differences in their sprinters.
Apologies for the long explanation here. I tried to keep the Newtonian model article as short as possible as well.
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Participant
I hope this is a valid question as I am looking for ways and means to translate some of your (and others) ideas into day to day sprint work.
I think I understand the time element but the question I have revolves around if when the “ground” contact is made in the running cycle makes any difference? Or is it strictly a matter of the length of contact time?
So for example relatively speaking if you are towing a sled during an acceleration the ground contact should happen in relatively the same body position as during an acceleration without resistance.
If you are doing step-ups, does the fact that your foot contacts the box (functioning as the “ground”) relatively “earlier” in the running cycle than “normal” make any difference? Since from observation I would say the “ground” contact on step-ups is longer than average since it takes more time for the athlete to be in a “completed” state. And if I can train the athletes to reduce that “ground” contact time on step ups, are the percentages good it will translate to reduced contact times during runs as well? -
Participant
Firstly, the article is not intended to be superior to other models because I haven’t yet found a model that attempts to convey how much resistance to train against when training for sprinting. Whilst various researchers show the force produced during the start, first step, second step, 14-16m mark and top speed of approx 9.5 m/s I felt the need to know how much force is produced during the entire acceleration. In this way, training methods could be modified or developed in order to be more velocity or movement specific. For example, when nearing maximum speed only between 10 and 15 kg of horizontal force needs to be produced although it must be realised at great angular velocity. Therefore, when doing an exercise such as cable-kickbacks one only needs to lift this amount and move the leg at a practical speed. Strength training with this specificity would allow an adaptation in the prime moving muscles that could be progressed over time.
This model is described as Newtonian simply because we use Newton’s equations of motion. It is intended to be simple enough to be able to supplement a coaches plan. The classical work of researchers such as Blickhan, Farley, McMahon (spring mass) or research work on energy systems are difficult to relate to training methods for most coaches. The tools readily available to coaches are resistance training, plyometrics, ballistic jump squats, Olympic lifts, hill running etc. for which I’m hopeful the Newtonian model can provide some guidelines (on horizontal force). The work of the respected aforementioned researchers on the contribution of elastic recoil of muscle-tendon complexes is appreciated in the calculation of forces produced per stride as the forces are as a result of such mechanisms. Instead of focusing on internal mechanisms that are rather complex, the sprinter just needs to know that they should produce a horizontal force of the order of 79 kg from a split stance that would replicate the stance in a starting block, in 300 milliseconds. If they can’t then why not? A coaching strategy could be to focus on speed of movement if the sprinter can lift this load already, and a reasonable guide is to be able to take a first step length of 1.23 metres as a result. From there the step length should increase gradually as this could make efficient use of fuel sources within the muscle. The Newtonian model is a guide, a point of reference to help coaches who I’m sure would not take the information as the gold standard and take into account the various individual differences in their sprinters.
Apologies for the long explanation here. I tried to keep the Newtonian model article as short as possible as well.
No need for apologies (i actually had to remove my quote to fit mine in here)
Your model still seems to lack or understate the elastic contribution to force, impulse, and power in acceleration. The percentage of elastic/eccentric/ssc force contribution to acceleration gets larger as time in acceleration grows larger while the percentage of concentric force contribution grows smaller as time in acceleration grows larger. There are two distinct phases of acceleration, three if you consider block clearance, a fast component which is the part of acceleration which is the first part of the velocity curve where the greatest amount of acceleration occurs, then the second part is the slow component which is the transition phase. The biggest difference between the two is stride rate drops and stride length increases, but speed still increases. In essence the legs work as adjustable springs and pistons in tandem during acceleration the former adjusting leg stiffness to compensate for the latter’s inability to produce force from concentric sources because of decreased contact times. The elastic recoil contribution to sprinting cannot be understated and it seems the Newtonian model you present doesn’t account for this.
To take this further into the application realm. I think trying to apply such a model would lead to what already occurs in European training, and to some extent Australia, and in many American HS’s and some colleges and universities. I see little cross-over possibilities with an unsupported movement such as cable kickbacks in enhancing sprint capabilities you get away from the specific needs involved in sprinting and sprint acceleration especially the latter portions of acceleration.
I feel the weightroom provides both general and specific benefits to sprinting in both max velocity and acceleration, but they are a bit different. Max. Strength increases force output potential and power work increases power output potential, both help in the creation of rate of force development, but there is little elastic benefit and any elastic benefit that can be attained in the weightroom would be considered by most as dangerous such as ballastic lifts which are not through full ranges of motion, but something I believe in.
Plyometrics seem to focus on reaction/contact times, but reaction/contact times are very activity specific. Plyometric training should be done to achieve greater stiffness and this seems to be landing specific which need to draw into and account for elastic feedback loops and how they affect the elastic structures.
For proper and enhanced applications of force to be attained the coach must be informed of the motor learning along with motor control and biomechanical aspects of sprinting first before trying to develop those qualities. The end product of many sprint training applications tend to produce either an athlete who can produce force extremely well, but has underdeveloped elastic capabilities who cannot maximize such force production at the latter stages of acceleration or it produces the athlete who has well developed elastic capabilities, but lack the force producing capabilities to maximize their elastic capabilities in acceleration.
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Participant
I hope this is a valid question as I am looking for ways and means to translate some of your (and others) ideas into day to day sprint work.
I think I understand the time element but the question I have revolves around if when the “ground” contact is made in the running cycle makes any difference? Or is it strictly a matter of the length of contact time?
So for example relatively speaking if you are towing a sled during an acceleration the ground contact should happen in relatively the same body position as during an acceleration without resistance.
If you are doing step-ups, does the fact that your foot contacts the box (functioning as the “ground”) relatively “earlier” in the running cycle than “normal” make any difference? Since from observation I would say the “ground” contact on step-ups is longer than average since it takes more time for the athlete to be in a “completed” state. And if I can train the athletes to reduce that “ground” contact time on step ups, are the percentages good it will translate to reduced contact times during runs as well?Never thought of this before but I think towing a sled would work best on a slight downslope. In this way you would get the extra resistance with good movement specificity to actual early acceleration phase in a way that may not adversely affect ground force production time. Has anyone tried this? As for step ups, the force production time would be too different to try to influence ground contact time and so any benefit to sprinting may need to incorporate a transfer method like plyometrics. I’m sure rapid step ups alone won’t make a difference you could feel but step up with a clean/snatch would encourage rapid hip extension that could well make a difference.
As for your question on whether it is the time of the ground contact in the running cycle or the length of contact time, I think that it is both. Time in the running cycle is best explained by Mann or Mike on foot placement relative to COM but no data could be provided that would allow me to analyse this for the Newtonian model. Clearly from other studies it can be seen that the ability to run fast demands that ground contact time reduces to below 100 and 90ms (with respect to the leg length of the sprinter). However, ground contact time is due to a few factors such as the ability of the muscle to contract quickly, the amount of force produced during the contraction, and the momentum of the leg prior to impact to name a few. Add to this the fact that the analysis revealed similarity in time between each ground contact which made me think of one word called resonance. I’m yet to develop a relationship for that yet (it’s very hard). I think dbandre knows a lot more than me about resonance because it refers to the behaviour of springs.
Hope that helps you enough.
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Participant
I hope this is a valid question as I am looking for ways and means to translate some of your (and others) ideas into day to day sprint work.
I think I understand the time element but the question I have revolves around if when the “ground” contact is made in the running cycle makes any difference? Or is it strictly a matter of the length of contact time?
So for example relatively speaking if you are towing a sled during an acceleration the ground contact should happen in relatively the same body position as during an acceleration without resistance.
If you are doing step-ups, does the fact that your foot contacts the box (functioning as the “ground”) relatively “earlier” in the running cycle than “normal” make any difference? Since from observation I would say the “ground” contact on step-ups is longer than average since it takes more time for the athlete to be in a “completed” state. And if I can train the athletes to reduce that “ground” contact time on step ups, are the percentages good it will translate to reduced contact times during runs as well?Thought I better pre-empt and clarify myself. Ground contact times are essentially determined by the rate at which one can move the centre of mass from when the foot touches the ground to when the foot can no longer touch the ground because of the fixed length of a leg. The rate at which one can move the centre of mass depends on one’s ability to co-ordinate the recruitment of muscles with the objective of moving the COM at the greatest speed. For this speed to be maximised, a compromise may have to be made between the force generated at each joint and the angular velocity of the hip, knee and ankle joints. That is why I think the step up with a clean/snatch would work better because one is encouraging the hip to extend as early as possible whilst the knee extends.
This concept might be more evident in the starting blocks if you concentrate on extending the hip as the first objective whilst pushing with the legs. See if that improves your 10m time at least.
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Participant
I think dbandre knows a lot more than me about resonance because it refers to the behaviour of springs.
I wish I knew more than you about it. Like I said I have been trying to do this for 3-4 years now after starting with a simpler model and trying to apply to weight room numbers and ultimately I have almost given up on trying to come up with a model that will help analyze deficiencies in a race. Instead my weight room workouts evolved to be shorter and less frequent with an emphasis shifting over the course of a season from larger range of motion in squats to smaller ranges of motion in squats. I also went to lighter but faster Olympic Lifts. I also complex my Squats/Deadlifts with an Olympic Lift following the strength lift about 40% of the time. All of these aforementioned items are something most on this board would disagree with. Another thing I do is drop landings and sticking the landing on drops cueing a stiff as possible landing in my plyometric routines.
On the track the my workouts move from more accel/maxV to more speed/special endurance throughout the season, i do have tempo endurance work throughout the season which keeps them fit enough to race the longer sprints while this transition occurs. My horizontal jumpers do this kind of stuff as well. They go from 4-7 stride approaches back to 6-12 strides as the season progresses.
To sum it up my approach is basically a developmental one in which the sprint training throughout the season mimics how acceleration in a race occurs going from less elastic training to more elastic training. Would this training work with and Elite Sprinters??? Maybe, Maybe not, I don’t really know, but it has been effective for myself and an improvement over former training methods and the methods seem to fit my cueing and feedback instruction to athletes better than approaches, but those too have evolved.
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Participant
[quote author="Jeremy Richmond" date="1222444243"] I think dbandre knows a lot more than me about resonance because it refers to the behaviour of springs.
I wish I knew more than you about it. Like I said I have been trying to do this for 3-4 years now after starting with a simpler model and trying to apply to weight room numbers and ultimately I have almost given up on trying to come up with a model that will help analyze deficiencies in a race. Instead my weight room workouts evolved to be shorter and less frequent with an emphasis shifting over the course of a season from larger range of motion in squats to smaller ranges of motion in squats. I also went to lighter but faster Olympic Lifts. I also complex my Squats/Deadlifts with an Olympic Lift following the strength lift about 40% of the time. All of these aforementioned items are something most on this board would disagree with. Another thing I do is drop landings and sticking the landing on drops cueing a stiff as possible landing in my plyometric routines.
On the track the my workouts move from more accel/maxV to more speed/special endurance throughout the season, i do have tempo endurance work throughout the season which keeps them fit enough to race the longer sprints while this transition occurs. My horizontal jumpers do this kind of stuff as well. They go from 4-7 stride approaches back to 6-12 strides as the season progresses.
To sum it up my approach is basically a developmental one in which the sprint training throughout the season mimics how acceleration in a race occurs going from less elastic training to more elastic training. Would this training work with and Elite Sprinters??? Maybe, Maybe not, I don’t really know, but it has been effective for myself and an improvement over former training methods and the methods seem to fit my cueing and feedback instruction to athletes better than approaches, but those too have evolved.[/quote]
Why would most on this board disagree with these methods? Larger to smaller range of motion in squats sounds exactly like I would do it. It is extremely specific and one can load up and create a response more akin to that encountered in actual sprinting.
Drop landings and sticking has quite a good efficacy on tendon/connective tissue strengthening. My only concern is that it is too much stress on the body which would explain the need to train less often. In terms of efficacy I was reading a thesis on drop jumping where the researcher proposed a method that had terrific results. I’m not disclosing it here but I wish that researcher would publish it.For now my understanding of the strengthening of the tendons and connective tissue has little to do with formulaes (causing massive headaches) and more to do with feel. I think we have all seen footage of the Jamaican’s doing a high knee drill on a road (warning- do not try this at home) that was uphill. I think this would create appropriate elastic resonance strength for sprinting.
By the way, the method you disclosed above about 4-7 to 6-12 strides etc. seems to have a similar concept to that in the thesis I mentioned above. Are you willing to give more detail on that method? Fully respect your decision if you want to retain the secrets.
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Participant
[quote author="dbandre" date="1222465563"][quote author="Jeremy Richmond" date="1222444243"] I think dbandre knows a lot more than me about resonance because it refers to the behaviour of springs.
I wish I knew more than you about it. Like I said I have been trying to do this for 3-4 years now after starting with a simpler model and trying to apply to weight room numbers and ultimately I have almost given up on trying to come up with a model that will help analyze deficiencies in a race. Instead my weight room workouts evolved to be shorter and less frequent with an emphasis shifting over the course of a season from larger range of motion in squats to smaller ranges of motion in squats. I also went to lighter but faster Olympic Lifts. I also complex my Squats/Deadlifts with an Olympic Lift following the strength lift about 40% of the time. All of these aforementioned items are something most on this board would disagree with. Another thing I do is drop landings and sticking the landing on drops cueing a stiff as possible landing in my plyometric routines.
On the track the my workouts move from more accel/maxV to more speed/special endurance throughout the season, i do have tempo endurance work throughout the season which keeps them fit enough to race the longer sprints while this transition occurs. My horizontal jumpers do this kind of stuff as well. They go from 4-7 stride approaches back to 6-12 strides as the season progresses.
To sum it up my approach is basically a developmental one in which the sprint training throughout the season mimics how acceleration in a race occurs going from less elastic training to more elastic training. Would this training work with and Elite Sprinters??? Maybe, Maybe not, I don’t really know, but it has been effective for myself and an improvement over former training methods and the methods seem to fit my cueing and feedback instruction to athletes better than approaches, but those too have evolved.[/quote]
Why would most on this board disagree with these methods? Larger to smaller range of motion in squats sounds exactly like I would do it. It is extremely specific and one can load up and create a response more akin to that encountered in actual sprinting.
Drop landings and sticking has quite a good efficacy on tendon/connective tissue strengthening. My only concern is that it is too much stress on the body which would explain the need to train less often. In terms of efficacy I was reading a thesis on drop jumping where the researcher proposed a method that had terrific results. I’m not disclosing it here but I wish that researcher would publish it.For now my understanding of the strengthening of the tendons and connective tissue has little to do with formulaes (causing massive headaches) and more to do with feel. I think we have all seen footage of the Jamaican’s doing a high knee drill on a road (warning- do not try this at home) that was uphill. I think this would create appropriate elastic resonance strength for sprinting.
By the way, the method you disclosed above about 4-7 to 6-12 strides etc. seems to have a similar concept to that in the thesis I mentioned above. Are you willing to give more detail on that method? Fully respect your decision if you want to retain the secrets.[/quote]
No secret about the short approach to long approach for jumpers. It comes down to their ability to accelerate and jump. What good does a full approach or near full approach work do for someone coming into the season? If I had a HS girl who can jump 14-15 feet starting at 4-6 strides they will end the season jumping 16-19 feet on 7-10 strides depending on their developed abilities and level of skill which was developed. Their competitors start on 7-10 strides and stay on those marks throughout the season, but they do not improve as much, regress, or get looked over because they were trained enough and lacked strength/power and/or acceleration(speed) to jump at such marks.
I see the reason as follows:
It lays a good foundation to work on acceleration pattern development progressively as the season progresses.
The starting distance doesn’t allow for speed generated from acceleration to excessive for early season jumps especially in GPP and SPP.
As the season goes along they will get faster and likely need to move back, and once an original mark moves back around 12-15+ inches it’s time to move them back farther and take more strides in the approach. The consistency on the board is enhanced too it seems, sometimes it gets iffy when I change the strides, but it seems to last a day or two. If a jumper cannot equal or better their previous PR’s when they move back you can scratch the idea.
It also creates a fall back as a jumper who might be struggling with fatigue I’ll allow the go back to their previous stride number and mark. It’s rare, but I have had to do this at the HS level especially at dual,tri, and quad type meets.
I also think it teaches mastery and competence to the athlete who then derives greater self-confidence in their performances. They notice themselves getting faster, stronger, and jumping farther, they get the feel of jumping while still accelerating, they hit the board more frequently than a majority of their competitors, their body and brains start to understand the physics involved and they become better able to relate that feedback back to me and it just seems to snowball from there.
As for the 1/4 and 1/2 squats to deep squat argument. There is a thread floating around this forum somewhere where I believe I was the only who advocated moving from parallel(3/4) to 1/4 squats as the season progressed.
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