[victorian]

victorian on May 8, 2006 at 6:54 pm #11828

Can anyone enlighten me as to why this is beneficial to max speed sprinting…. the straight leg part , not the under the center of mass part.
Thanks in advance.
Also, if the leg is straight, which muscles are responsible in projecting the hip forward?

[pzale8018]

pzale8018 on May 8, 2006 at 10:36 pm #53315

In a nutshell… having a straight leg under your COM during sprinting allows you to push off a stiff segment.  A bent leg has much more give than a straight leg.  Any give in the leg is only going to slow down the next movement.

Second question…  the muscles responsible for projecting the hips/pelvis forward during sprinting are the hip extensor muscle, gluteus maximus and hamstring group.

[victorian]

victorian on May 9, 2006 at 6:21 am #53316

In your opinion, what are the attributes needed for an athlete to execute this movement (Straight leg landing under the COM) @ v.max? How do you coach this?
it's one of the challenges i have in trying to teach 13- 16 year old kids.
Also,what are some things that you think works in shortening the give "Amortization" phase?

[pzale8018]

pzale8018 on May 9, 2006 at 10:35 pm #53317

To coach a straight leg, cue your kids to "run tall" or "keep the hips high" things like that.  That will get them thinking about being taller, thus a straighter leg.

The same cues should help reduce that give during the stance phase of sprinting.  Also, cuing them to get their feet off the track with stuff like "running on egg shells" or "the track is hot" may help as well.  Just be careful with these that the kids don't start giving up the push to achieve this.  You do NOT want them tip-toe-ing down the track.

[victorian]

victorian on May 10, 2006 at 5:52 am #53318

Thank you PZ8018 for your insights, any thoughts on how to reduce the give, with respect to exercises or drills and do you guys work the specific muscles that "project the hips/pelvis forward during sprinting "? Straight leg bounding?Anyone?

[pzale8018]

pzale8018 on May 12, 2006 at 1:19 am #53319

If you try and cue the kids to "squeeze their butts" under them, this will keep the hips underneath the body, with an anterior tilt, and allow them to lift the knees better throughout the sprint.  A strong core will pay dividends in helping keep the hips under the trunk. 

The wieght room will help with this too.  Anytime you have weight either over your head or on the shoulders, you automatically keep the hips under the body.  So squats, cleans, snatch will all help reinforce an anterior pelvic tilt.

[victorian]

victorian on May 12, 2006 at 10:03 am #53320

Mike said something about high speed amortization strength as being a very important consideration. Any insights on this?

[Mike Young]

Mike Young on May 19, 2006 at 8:57 am #53321

Mike said something about high speed amortization strength as being a very important consideration. Any insights on this?

What I was referring to is the development of fast-eccentric strength. Maintenance of top end running speed is largely dependent on the ability to generate vertical forces. This is a byproduct of both mechanics (especially position of the leg relative to the COM at ground contact) and the capabilities of the athlete. These two factors are inseparable. The latter can be developed by plyos, depth drops, and specific weight lifting exercises.

ELITETRACK Founder

[victorian]

victorian on May 24, 2006 at 8:06 pm #53322

Mike, could you enlighten me which specific weight lifting exercise?

[Mike Young]

Mike Young on June 1, 2006 at 12:57 am #53323

The actual exercise isn't really the important thing so much as the PERFORMANCE of the exercise. That is, heavily loaded fast eccentric strength work or exercises performed to develop reactive strength. Squats, single leg squats, etc. could be used in this manner.

ELITETRACK Founder

[mharris]

mharris on June 20, 2006 at 10:49 pm #53324

so you guys are basically saying that at the start of acceleration, you should keep your feet under the COM to generate power thus generating speed. But somewhere in the top speed phase, in order to maintain your top end speed you should use more of your hamstring and keep your leg staight and in front of the COM?

[jjh999]

jjh999 on July 6, 2006 at 3:39 am #53325

Can anyone enlighten me as to why this is beneficial to max speed sprinting…. the straight leg part , not the under the center of mass part.
Thanks in advance.
Also, if the leg is straight, which muscles are responsible in projecting the hip forward?

I'm not sure if this has been answered, but the key thing is achieve a position where the COM is as high as possible prior to ground contact (i.e. a hips high position, stop the fall as soon as possible).  A straight leg at ground contact is a good indicator of that position.  Relaxation and allowing the ground to come to you are good cues/reminders to help attain that position.  The fact that the leg may be straight at ground contact, however, does not mean that the joint will be stable eccentrically through early, mid, late ground contact and the eventual pushoff.