Do you think the propulsive mechanism in maximum velocity sprinting is more of a push (where knee extensors are primarily responsible for force) or a pull (where leg extensors are primarily responsible for force)?
ELITETRACK Founder
Sprinting: a push or a pull?
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Keymaster -
Participant
I think its both, it all depends upon how you look at it. If you have taken a physics course you know that its a pull but logically its a push. The reason its a pull is because you are trying to pull your leg forward but the frictional force is acting in the opposite direction. It is also a push because logically you are pushing off your feet and toes applying a force to the ground and it applies a normal force (as its called in physics) on you pushing you in the opposite direction you applied the force (every action has an equal but opposite reaction). 🙂
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Keymaster
Daa-
I'm not following what you're saying here, please explain:[i]Originally posted by Daa20[/i]
If you have taken a physics course you know that its a pull but logically its a push. The reason its a pull is because you are trying to pull your leg forward but the frictional force is acting in the opposite direction.ELITETRACK Founder
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ParticipantThe action of the movement is a push, muscles are pulling the levers, but any efforts of pulling back is a injury waiting to happen.
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Participant
phoenix,
is that link,, http://www.regenerationlab.com your new site? when will it be up? -
Participant
There will always be some pull when sprinting because the foot touches down infront the com.
True, the touchdown occurs slightly ahead of COM, but don't forget about momentum…the COM will still be moving forward at touchdown…Proper sprint technique at touchdown involves the stabilzation of the COM over the touchdown foot (amortization phase, hopefully as short as possible) followed by the forceful extension of the hip via the hamstrings in order to project the COM "up and forward" to maintain the forward motion.
(note: my comment refers to maximum velocity, not acceleration)
I think it's a pushing action. I'm not too dogmatic on most stuff, but any cue about pulling or clawing is bad news IMHO…
😉
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Participant
[i]Originally posted by JJ[/i]
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I think it's a pushing action. I'm not too dogmatic on most stuff, but any cue about pulling or clawing is bad news IMHO…😉
ok… i'll play devil's advocate here…. why is the cue bad news if it gets the athlete to do what **you** want. i mean i tell kids who overstride to "be quick at the end" all the time. maybe they just don't feel it as a "push" but as a pull w/a certain part of their body…
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Participant
Ok, Mr. Devil, errr Satan, errr Mephistopheles…
You know why I don't use the pull cues…take a look at one of your Tellez "lecture tapes"…
Seriously, though, I don't use any cues involving pulling, b/c so many of the kids that come to me at the DIII level have already mastered that skill unfortunately… Still too many coaches teaching them to drive their knees high and reach out with their strides…I spend the majority of my time during an athlete's first year with me fixing that…
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Participant
I think what we are debating is the physical actions of the body, not perceptions of the athlete. Like what Kebba said earlier, any drill that helps the athlete do the right thing might be good…..my question is when this cue ages does it cause harm later on. If someone stops overstriding and then starts to actually pull back after progressing then the cues should be changed to something even more subtle, then perhaps all cues would be dropped when at WC level.
Quick,
My site should be up in a few weeks. It is not going to be another forum, it will be just a blog site with great products, articles, interviews with world class experts in sports training, and reviews. I wish to thank Mike for his understanding with my shameless act of self promotion!
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Member
"To minimize the touchdown distance, and get the most out of this action, the sprinter must be very strong in the hamstrings and gluteal muscle since these are needed to pull the body over the touchdown point during the initial portion of ground contact. More than any other factor the strength of these muscles dictate the success of a sprinter. Pulling the body over the touchdown leg in the first 20-30% of ground contact is the only way to produce the needed vertical forces economicaly"( Ralph Mann)
Thoughts?
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Participant
this might take the conversation in a different direction …but….
I would second the comment about being ahead of the COM and pulling back, and I would add that if you look at most muscle strains that occur….its at the hamstring…which come from the extension of the hip, not the flexion of the knee. So I feel that more time should be spent on strengthening the hamstrings this way. Its more applicable to the training and technique of the sprintsthe first few steps in the hundred however should be seen as push…..as they are more piston like…..once you get rotary….its a pull.
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Participant
once you get rotary….its a pull
at first id agree, but at maxV the the power applied is vertical, not horizontal (if i aint mixing things up here!?), as mike writes in the FAQs or classics, dunno. so landing in front of the com, the leg is being mostly pulled back by the gluteus etc.(=hip extensors?= pull), then it goes over into a push as you straighten the leg, however not to push yourself forward. the push being behind the com at this point is just an adaption to the high speed. probably the most interesting phase here is the part right under the com which gives you the most vertical thrust to create more hang time.
so its the phase under the com being relevant, and if thats equal to the transitional phase between push and pull (which i dont know) we have a combination of the two being important for maxv running. the pull however being the initiator of the movement up to this point should be more releveant, as the push phase is gradually loosing its ability for upward thrust going behind the com. -
Participant
yes it's center of mass
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Participant
One thing to keep in mind is the time lag between a muscle group's contraction and the resulting limb action. For instance, even though the glutes and hams do contribute to "pulling" the COM over the point of contact, most of their work is probably finished during preparation for ground contact as they generate negative foot speed. At contact, vastus medialis and hip flexors are already beginning their elastic contractions as "pushes" which keep the hips high enough to allow for an early toe off. In other words, a muslce's action is sometimes out of phase with the effect you see on the track.
This is why cueing is so important. Both push and pull cues can be interpreted badly and prolong contact time, since in order to actually perceive the push or pull sensation you usually have to hold toe contact slightly longer. A more continous cue that relates to the action as a whole I find is better, like "up and down", "step over" or whatever.
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Participant
i just saw coach tellez this spring, we all know this theory. so i do believe in the push theory. after his lecture he spent a good 15-20 minutes with me so i could "feel" the push. it was excellent and probally one of the most exciting moments ive ever had as an athlete.
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Member
its definitely both. while one leg is going through the push motion, the other is going through the pull motion.
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Keymaster
its definitely both. while one leg is going through the push motion, the other is going through the pull motion.
I understand the pull part of your comment but the push??? What is the other leg pushing….the air?
ELITETRACK Founder
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Participant
The ability to produce as much force against the ground in smallest possible time means it has to be a push, because a pull increases ground contact time and increased gct = slower speeds.
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Keymaster
The ability to produce as much force against the ground in smallest possible time means it has to be a push, because a pull increases ground contact time and increased gct = slower speeds.
To be a devil's advocate this isn't necessarily true. In fact, the fastest people are the ones who have negative foot speed at ground contact (maybe indicating a pulling motion) AND the shortest ground contact times.
ELITETRACK Founder
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Participant
What mike and Flow have said is true. The sprint stride is a combination of both a push and a pull, but the whole stride itself i dominated by the actions of the biceps femoris (part of the hamstring group). This is given support by an article that mike posted here on the site, entitled "Kinematic, Kinetic & Electromyographic Characteristics of the Sprinting Stride of Top Female Sprinters." Data from this research states that, based on EMG data collected, the biceps femoris, primarily a hip extensor muscle in this case, is one of the most important muscles involved in sprinting.
At contact, vastus medialis and hip flexors are already beginning their elastic contractions as "pushes" which keep the hips high enough to allow for an early toe off.
I'm not exactly sure where you're going with this. Yes, I agree with the sentiment of the post, saying that the action of the limb is slightly out of sync with the contraction of the muscle fibers themselves, but not by very much. I guess I don't see how you think that the vasti and iliopsoas are contracting to flex the hip at contact. Flexing the hip too close to initial foot contact would yeild a "tip-toeing" type of movement, which I think we can all agree is not the best thing for fast sprint times.
Also, if I'm not mistaken, and mike, please correct me if I am, don't elastic contrations take place AFTER the muscle-tendon unit has been sufficiently stretched. That being the case, an elastic contraction of the hip flexors wouldn't take place until well after foot contact, when runner is completing toe off and the hip flexors are stretched to their fullest.Clarify what you mean for me, because I'm not getting what you're shooting for here.
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Participant
wow so the biceps femoris tends to do more hip extension work than the gluts during sprinting? i remember reading that article, but this info just occured to me now…
btw when i posted first i had a slightly different comprehension of push and pull than i assume would be right today. my thoughts havent changed, however with my new perseption of the words id like to state that in my belief the push is the overwealming part during maxV running. : P
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Participant
from what i understand sprinting is a push and a pull simulaneously. the leg in contact with the ground has to apply force in two dimensions in order to sprint. first, at foot strike, the leg must stabilize and counteract gravity by pushing the ground, but at the same time the leg must pull the body over the point of contact. that is why sprinters have large hip extensors/hams and glutes and hip flexors/quads.
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Participant
i think its definately a push. there is never a time in the sprints when you should feel like you are pulling. biomechanically speaking, it has a pull aspect, but i think the pushing is far more important.
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Keymaster
i think its definately a push. there is never a time in the sprints when you should feel like you are pulling. biomechanically speaking, it has a pull aspect, but i think the pushing is far more important.
I tend to agree. I think that cueing athletes to push and having them feel a push is more important than a pull. I am very much anti-grab / pull for teaching sprint mechanics but that is not to say that it doesn't happen. I think having athletes feel the vertical push helps to set up better leg stiffness at ground contact, facilitates a more efficient contact position, and activates the muscles in a more appropriate sequence.
ELITETRACK Founder
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Participant
[quote author="cockysprinter" date="1153694656"]
i think its definately a push. there is never a time in the sprints when you should feel like you are pulling. biomechanically speaking, it has a pull aspect, but i think the pushing is far more important.I tend to agree. I think that cueing athletes to push and having them feel a push is more important than a pull. I am very much anti-grab / pull for teaching sprint mechanics but that is not to say that it doesn't happen. I think having athletes feel the vertical push helps to set up better leg stiffness at ground contact, facilitates a more efficient contact position, and activates the muscles in a more appropriate sequence.
[/quote]In terms of cueing the athletes, I completely agree with sprinting being a push. I would never want my athletes feeling like they are pulling themselves over the ground during a sprint. That sets them up for way too much injury.
I agree with mike, in that thinking push sets up much better leg stiffness, better contact position, etc, as was said above.That being said, when thinking about the muscles that dominate the action, pulling is definitely what happens, tho again, i'd never cue that.
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