An oldie from John Smith on getting the back foot on the pedals.
2:20 or so https://www.youtube.com/watch?v=j8f5RKY9NCs
excellent, I do hate getting to meets with thos fixed one angle blocks, and then not having a chance to find a setting
Jimson Lee at speedendurance.com talking about stretch reflex in the blocks (at about 6:00):
http://speedendurance.com/2011/12/13/how-to-use-starting-blocks-analysis/
Carl Valle about stretch reflex overcoming inertia:
http://elitetrack.com/blogs-details-6787/
The action is really Newton’s Third Law: The heel goes back, causing more explosive force forward. To do this, the block must allow the heel to go back–which the high blocks in pro meets do not allow in most cases–but if there is too much gap, you get a lag effect.
This is Jeter, who is coached by John Smith, in a slow motion start. Notice that the rear heel is not literally “on” the pedal, and that’s for the stretch reflex to work:
https://www.youtube.com/watch?v=BWdy6mBSxIY
The sport does progress over time. What Smith teaches now is not exactly what he taught 15-20 years ago, just like if you look at Asafa or Fraser-Pryce in slow motion, you will not see them flicking the lead wrist like Ben (you will see them pulling the trail arm more).
Also notice in the video with John Smith that Stikki posted that the rear block was on minimum angle and what John Smith was actually doing. You do not move the rear pad angle up: You move the foot angle (almost) down to the block.
I always appreciate your posts and thanks for sharing the links.
I am very curious what JS was teaching in 2012 regarding the arms at the start. Any changes or interference from an outside party that year close to the games. Again…just curious.
If you look at the Torpedo during his start in the 12 Final one will notice his left/leading arm goes way too high.
Also, Jeter what was she focusing on in practice before those games? Her 4th stride…
There are some interesting papers written by couple of guys (Cousins and Dyson (2004) and couple other when I find in the library I’ll post it, actually some info you can find in this article Biomechanical investigations of sprint start technique and performance,
http://community.charliefrancis.com/showthread.php?22587-Interesting-articles-websites-researches-etc� ) who were testing stretch reflex in blocks and application of forces.
The researchs found that the lower the angle of the pad on the back block the higher the levels of force. From what I remember highest application was at 30 degrees. Lol. 30 is where most manufactured blocks won’t go.
I saw some guys experimenting with putting mid foot on the upper edge of the block to create even greater stretch reflex. It worked for them.
The Gill Fusion blocks (the adjustable ones) have a minimum angle of 30 degrees. The problem with them (besides the $400+ cost) tends to be reliability with frequent use. They work great at championship meets, though. I never understood why they make fixed pads for high school with high angles–every piece of research I’ve seen says that the lower the angle the better.
James,
Any chance you can expand on the straight arm longer lever creating asymmetrical thoracic rotation? Looking to get better handle on causes and solutions.
Thanks
Hello Ollie, it’s actual quite simple. Consider the factors associated with moment arms, lever lengths, horizontal distances from axis of rotation, resultant angular velocities and so on.
One arm, in which the elbow is relatively fixed at 90 degrees (less in front and more in back) is a much shorter lever arm throughout than the opposing arm that fully extends during the backside action.
Given that both arms behave similarly during front side action, then differently during backside action, would suggest that the longer lever arm (the elbow that fully extends during backside action) generates greater momentum and, by association, greater torque against the rotating axis (shoulder and thoracic spine).
Thus, my suggestion to have a look a high speed/high resolution film from the front is rooted in my interest to see if there is an outwardly visually observable asymmetry between the amplitude of thoracic rotation to the right and left. This would be made evident by observing the scapular plane (clearly most so by way of an arial/axial view).
If there is a marked asymmetry occurring, this would also likely effect hip rotation and, by further association, stride length. As to whether all of this would result in measurable differences in sprint time is the ultimate question.