2) Arm Action. Remember the previous debate forum?
3) Femur velocity of elite runners compared to Chrissy from Bedford Massachusetts in the harvard study.
4) Stride frequency of maximal speeds of both elite sprinters and average runners.
I have no fear of change. In fact I am the root of it!
These issues have a 20 year trail in the scientific literature that most have no familiarity with b/c it is outside the sport science literature. It would be unfair for me to try to give it justice with out the background that Peter has.
I don't know of any studies that looked directly at arms in sprinting at max velocity. There are lots of numbers for mechanical work done by the arms, but these are not very informative regarding functional importance to sprinting or speed? If you have some post them. I want to see them.
From a purely mechanical perspective, steady-speed walking or running on an adequate motorized treadmill is identical to overground walking and running; the only difference is the frame of reference for each situation (23). Locomotion on a treadmill with inadequate power or momentum (i.e., no flywheel) does indeed differ from overground locomotion. However, on a treadmill with an adequate motor and flywheel, where the belt speed does not vary, the kinematics (21), ground-reaction forces (19), and metabolic cost (2) of locomotion are nearly indistinguishable from overground locomotion. As detailed above, our motor and flywheel appear to be adequate in maintaining a constant tread speed
This is very nice...
"The problem, said Rodger Kram, now in the Department of Kinesiology and Applied Physiology at the University of Colorado, Boulder, is that treadmills in use today are not very effective, primarily because they rely upon awkward and uncomfortable rubber bands to pull astronauts down onto the treadmill as they run..."
"I have said this before. You dont want to
teach a pawing of the leg cause it disrupts the spring model and also forces an abbreviated ground contact time which hinders the impulse
(vertical force X contact length).
Increased Knee flexion, ( when angles shorten at the knee joint), during recovery phase allows for improved knee lift or hip flexion, this sets up the leg for higher force during the down action of sprint due to pre stretch of gluts( length-force relationship).
This action is distinctly different from pawing or pulling, the leg down.
The Harvard study is limited, like other studies in sprinting, force plates can measure GRF, but they cannot measure force contributions of specific muscle groups prior to or during contact, currrently technology does not allow us to measure forces of specfic muscles to during the sprinting.
Science can hypothesize muscle contributions based on known action and Laws of physics.
Extreme Dorsi-flexion of the foot, increases microtrauma in the achillies tendon due to increased eccentric load.
Could you give your view on dorsi flexion of the foot?
RememberI run on a treadmill. Why,it is NEARLY indistinguishable.
Why is this forum? Let's look at this by reading the study with great care. Remember that the graduate student walked and ran on the treadmill.
Running is not sprinting.
Sprinting increases newtons to point were a AMTI force platform would have no use when the motor (in the study)is only able to go to 7.0 meters per second! When the speeds are at 9 m/s the belt pull will cause an artificial gait change. (Davis 1997) Why friction at top speed is slightly less on a treadmill and each stride is not uniform. Even Charlie knows that(too bad he only attended Stanford)
From a real and practical angle, look at the USATF indoor nationals in 2000. The men's 60m final an athlete (save face here) fell at 50m! This was not at top speed. The demands of the ground contact are so high, even a 100% is tough for the body, never mind a 1-2 cm difference (Kram et all.
This why fat Joe can run on a treadmill at 28 miles per hour when a person has support behind them...
Dan The speed was at 1.25 mps and 3.0 mps. The frequency was almost perfectly equal.What about 11.5 meters per second? No research has been done on this because you need an elite sprinter to be able to jump on a treadmill at 27 miles per hour? Even Neo from the Matrix would have a hard time doing this.
"Woooh" - Keanu Reeves
Page 6 was funny when they tried to put two treadmills side by side to measure each foot independently, but the student look like a cowboy because they couldn't squeeze the treadmills together close enough.
Dan, I respect Rodger greatly. He got his PHD from Harvard in Organismic and Evolutionary Biology. His penguin research and outer space stuff was interesting, but we are sprint coaches, not walking grannies.
Hmmm, every sprinter I have come into contact with will do whatever is takes to avoid running on a treadmill.
I think there's a message in that for all of us
Too bad Harvard(the Stanford of the East)doesn't have the weather to conduct research outside. Surely, this must be the reason they restrict themselves to a treadmill deep in the bowels of the University. Kinda like research into sex- they've heard of it but never done it- want to know more about it -so they've created computer models for study. (More relevent research might justify staying inside)
Dan writes
"Know the tredmill results came out within in 1% accuaracy of the flat ground testing. "
It's only 1%.
If this was ok, then talk to all the blind people from lasix surgery!
10,000 babies given to the wrong parents a year? 99% is not good enough.
99% off of 10.05, 9.94 is close enough for me.
Still the treadmills have a fatal flaw. They are perfect! The human body is not perfect. Take a look at the research done on Merlene Ottey. She slows down during meters 38-40. Why? Perhaps what charlie states in Speed Trap is true about breathing patterns and accleration. So if she is running on a treadmill what do you think would happen if she slowed down slightly at top speed Dan?
This is why the treadmill needs a laser tracking device for the athletes to monitor the COG during sprints so they don't trip or stumble at 27 mph.
Any treamills do that? NO.
Fact.
Kinetics and Kinematics are not the same.
Force plates yes.
Treadmill no.
I am in favor of treadmill testing for lactate threshold and VO2 max testing. But even that work is limited.
As for reaserch on arms use medline for the last name, and date of publishing.
Dorsi Flexion,
The question is does this happen, and if so, how much, when, and why.
This was always a mystery to me. How do you run on the balls of your foot and toe off when you are suppose to dorsi flex? So instead of reading I went outside and ran my sophmore year in High School.
The results and observations I did were clear. The body dorsi flexes the foot before
contact.(McGinnis 1998) It hyperextends the gastroc from the suport phase then plantar flexes later. This should be natural, but other external problems may cause a temporary loss of some of that function.
As for pawing action lets look of cats. This seems logical. Humans have spikes to increase friction while a claw is better then we can design for various reasons.
www.cs.caltech.edu/~klavins/papers/NBR.pdf.
While much of the forces generated by the brain are vertical in nature. There is a tiny pull. This is insignificant for training purposes. At high speeds the ground is passing through at 26 miles per hour, causing much of the illusion that we see.
But be warned because there is only a brief explosion, doesn't mean the body is simply bounding from step to step. Because much of our evolution is based off of simple mammals, the hamstring pulls by it's insertion and origin.
In closing. Don't try to pull your way through!
Naturally Dorsi flexion, precedes planter flexion,
However the question is , what angle should the foot dorsi flex prior to ground contact and during support for max velocity,?
To maximise force generated by the agonist during support, it is necessary to minimize amount of co-activation of antagonist and agonist muscles.
( Sports Med, Neuromuscular junction)
Trying to "slap" more force down on the track, will do the opposite, relaxation assists in minizing co-activation, not tension like slaping or pulling.
Most strength gains come from this neural change rather then hypertrophy during the first 8 weeks of training.( J. applied physiology, Hagerman).
Charlie, hi I am new to the board. I was wondering if in fact you feel there is a need for doing skipping and hurdle drills. I see a lot of coaches implement them into warmups...but what purpose are they serving, looks to me like they just waste a lot of energy that could be spent on sprinting. I mean a lot of high school kids need coordination and flexibility to even get them to understand timing and rhythm, but is it necessary to do them when you are very proficient at them?
For the 100m sprinting, how important is the Anareobic threshold, ( also known as lactate threshold, and Onset of Blood lactate), do 100m
sprinters need to develop there lactate system, and at what intensity should they train there lactate system?
For the best book on lactate training read the Science of Winning. by the great Jan Olbrecht.
www.lactate.com/bkolbr.html
The solution is simple and I agree with Charlie on 92% of all of his tempo programs. Except for doing two weeks of inter-special endurance runs for 400m runners. Sprint the special enudrance runs at near maximal speed. The distance and intensity of those runs plus the tempo work will overlap all of the needs for a 100m athlete.
If anyone can recall the talk about the 1-1.5 second addtion of alactate work Charlie was talking about (his seminar or the thread about fall training) was spine chilling.
I like this Quote I found in a T&FN from Charles Foster of he said "To run on natural talent is one thing. If you align some of those misaligned motions and then apply the same forces, the clock seems to tick slower"
To maximize force generated by the agonist during support, it is necessary to minimize amount of co-activation of antagonist and agonist muscles.
I don't agree with the minimize part, isn't it maximize during support, then minimize during the elastic phase?
Please break down your thoughts on the support phase in great detail to make sure we are on the same page.
"To maximize force generated by the agonist during support, it is necessary to minimize amount of co-activation of antagonist and agonist muscles."
"I don't agree with the minimize part, isn't it maximize during support, then minimize during the elastic phase?"
Ok, my above statement can be misleading; during support, the aim is to maximize contraction of agonist, and minimise contraction of antagonist. If both where to have equal force, agonist (shortening) and antagonist (lengthening) then a breaking force would be applied, like when you trying to decelerate.
So by reducing eccentric forces within the Hamstrings ( antagonist) and maximizing forces in the quad extensors (agonist), GRF will be higher since the leg is not working against itself,
Co-activation is when high forces in concentric and eccentric muscles occur simultaneously.
However the question is , what angle should the foot dorsi flex prior to ground contact and during support for max velocity,?
Let’s try this again; the limb is "pre-tensed". This happens with muscles and nerves in almost every situtation beofre a force is applied to any object - there must be 5,000 or more published EMG and other measurements that show
this... The friggin dorsiflexion muscles pre-tense in the wrong direction - running forces are applied down into the ground, not up toward the head as the dorsiflexors would cause to occur.
Besides, the dorsiflexors also are ridiculously small and weak....
Landing in plantar flexion is not going to hurt the spring. Remember it is a quite natural thing (the spring model). The body, depending on the ground support forces will take care of that.
The force and energy loaded into the achilles by dorsiflexing is a ~ linear function of the distance the achillles is stretched. The force the body's weight exerts on the ground is > 2 times body weight; the force the achilles experiences is probably 5 times body weight and roughly 10 times that the ankle flexors can generate while dorsiflexing the ankle in mid-air. Thus, any dorsiflexion achieved is completely swamped out by the ground forces during the contact phase.(Weyand) I attatched this part on a different forum...
Weyand cant see why one would want to dorsi-flex. Again, any force transmitted indirectly (to the achilles and later the ground) from the ankle flexors is trivial in the grand scheme of the ground and extensor muscle-tendons forces that occur in the middle of the stance phase at which time they reach their peak. Furthermore, the force loaded by dorsiflexing in mid-air, if it could be released would be released on touchdown when the horizontal forces are negative and therefore slow the runner down.
This begs the simple question of why one would want to use swing phase muscle action to increase the braking action on landing? The reason the force of dorsiflexing cannot be released in any meaningful way on touchdown is simple and can be observed simply by watching the foot and ankle joint (without any measurements) from a slow-mo video of the stance phase. The ankle continues to dorsiflex through the first half of the stance phase. This indicates that the achilles forces are increasing throughout the first half of contact. In order for dorsiflexion forces and energy loaded in the swing phase to be released, the ankle must move in the opposite direction (i.e. plantarflex) and this does not occur. The force of the body's weight as it loads the leg all the way down to the ground causes progressive dorsiflexion throghout the first half of the contact phase.
As noted above, these body forces exceed the forces the ankle flexor could generate by roughly an order of magnitude and summing does not ocur - i.e. dorsiflexing while loadng cannot increase these forces further. Even if the latter were possible it amounts to madness since it would elevate the force required in the extensors above the outrageous forces they already generate(Weyand).
Does the ankle joint dorsi flex at all during the swing phase?
Naturally, yes I would imagine. But why would it matter. It should be natural.
Furthermore, tibialis anterior is a muscle responsible for approximately 85% of the gait cycle of which 25% is during the stance phase (Mann et al., 1986). These muscles therefore can fatigue easily in high intensity exercise and their true function may be compromised.
See the drawing of the leg in Charlie’s older manual, the CFTS.
"Furthermore, tibialis anterior is a muscle responsible for approximately 85% of the gait cycle of which 25% is during the stance phase (Mann et al., 1986). These muscles therefore can fatigue easily in high intensity exercise and their true function may be compromised."
All Flexor muscles in the body, fatigue before extensors do, they also contract at a faster rate, due to higher Fast twitch a fibres. They have lower force capacities then extensors and have higher incidence of injuries( hamstring strain).
Sprint training should be aimed at balancing the strength gap between extensors and flexors.
Movements should not isolate one muscle group e.g Hamstring curls, exercises involving recruitment of multiple muscle groups, develop greater strength gains.
Strengthening the tibialis anterior by dorsi flexion exercises may assist sprint performance, however accentuating extreme dorsi-flexion during sprinting can lead to injuries by increasing load on achillies tendon.
I don't know of any studies that looked directly at arms in sprinting at max velocity. There are lots of numbers for mechanical work done by the arms, but these are not very
informative regarding functional importance to sprinting or speed?
While not every research study will tell all of the secrets of the sprints, many will give a great piece to the puzzle. On the arms I have listed both the name and year of the study. I sometimes give the page number to books as well. I even do this with Charlies books.
I feel that anyone who posts in this forum has the right to voice his or her opinion. With this right, they are subject to the review from other members. I use some graphic illustrations to make the point sink in.
For example "at top speed the arms are not important."
I responded with a sarcastic remark of "run like a vampire" to use both humor and logic in a clear visual to show that this is foolish.
Even the poor NSCA knows this information! In the speed section Steve Plisk writes:
The role of arm and torso action during sprinting is twofold. One is mechanical, as the axial angular momentum resulting from forward/backward leg movement is offset via contralateral arm action and trunk rotation. The other is neuromuscular and relates to central innervation patterns. In any case, explosive arm action should be approached as means of facilitating leg action.
The references were piggyback (other people not straight journals) so I had to find the direct sources like the my arm section posted in the arm section.
If indeed this is the case, (the faster the pawing/the greater the ground force) then it is difficult to explain how athletes are achieving faster top end speeds when swing times (of which the classic
"pawing action" in conventional sprint training models is definitely a part) are virtually the same for athletes sprinting at their highest possible meters per second, which is what the study clearly shows. If active muscle power were the key, you would see faster swing times for sure!(or for that matter why wouldnt we?)
Claiming that the research team has confused swing time with rate of swing, which is what some appear to be doing is really not a valid arguement. Remember that four years worth of research went into this project, and even though Peter's group had a theory as to how athletes achieve greater speed, they did not know where the data would lead them. It all leads back to the ground support forces time and time again.
In the scientific world, if we disagree with something, we do our own study or find studies which refute the findings.
Well it makes sense about rate of swing - doesn’t it? If, for example, two people do a vertical jump in the same time, but one has longer limb lengths, there is obviously more power in the jump with the longer legs. How can you dispute this?
So it follows that length of stride also has to come into play, as well as limb lengths. To say that everyone, no matter what their limb length and stride length (which can be affected by many
So it follows that length of stride also has to come into play, as well as limb lengths. To say that everyone, no matter what their limb length and stride length (which can be affected by many