Barry???s response to my explanation of the role of the arm swing:
Hmmm, Mike on reply #45
"Perhaps you should explain to Dr. Mann and the numerous other researchers who've produced similar results that they are all wrong."
1: Med Sci Sports Exerc. 1981;13(5):325-8.
The relatively small upper limb muscle moments seem to relegate the arms to the simple role of maintaining balance.
Perhaps you should tell Ralph Mann he is all wrong?
Don't see much about altering leg and pelvic positioning from Mann.
Doesn't seem to say much about the trunk rotating out of control either.
It's a very clear statement about the arms.
So is Mann right or wrong?
You see Barry, one of the main differences between how we look at research is that I look at ALL the research and base my decisions on those researchers who directly examined a subject using the most optimal research methods. In the case of examining leg swing kinematics, Mann has examined over 20 years of kinematic leg swing parameters of elite sprinters and come up with conclusions on leg swing kinematics that I have seen little to dispute. I am not aware of any researcher who has examined the leg swing kinematics of either such a large sample size or such an unbelievable population as Mann. As such, I consider him the foremost authority on the subject.
In the case of ground contact kinetics, Weyand is one of several researchers who I believe have produced some very good research on the role of force application to sprinting. Weyand???s study was indeed very important. He has not however examined kinematics to nearly the same extent as Mann (in fact, he???s not even in the same ball park) and as a result I???d prefer to go with the conclusions of Mann when speaking of leg swing kinematics.
Likewise, Richard Hinrichs is one of the only researchers to extensively examine the role of the arm swing during running and sprinting. Far more so than Mann, Weyand, or any other research I am aware of. Much like leg swing kinematics was the focus of Mann???s research, the role of the arm swing was the focus of Hinrich???s research. As such, when discussing the role of the arm swing I prefer to use the person I consider to be the foremost authority on the subject.
I'm well aware that force is a vector. I'm certainly understand how force plates work. I also know that they don't have a brain so they don't care about what direction force is coming from, they merely measure the force that hits them, regardless of the direction, and show how much the force was.
I don???t know why I keep arguing with you about this as you are indisputably wrong. You can???t register force and ignore the direction it comes from. End of statement. I think your hang up is that the direction is often implicitly assumed. It seems you only care about vertical force production. When an athlete hits the ground they register force in all three directions. Often times, research papers focus on only one or two directions. This does not however mean that force is not registered in the other directions. Nor does it mean that it is unimportant.
This is what a high speed trace looks like:
Oh, you already know this Mike? Then why the schematic? Because you can't account for where force peaks and you didn't want to show something that doesn't fit with your theories?
This only serves to prove your ignorance of force vectors. Why do you only point to the Fz curve? Is it because you only consider force application in the vertical direction? Why ignore the Fy curve? Is it because you don???t understand that the graph is depicting force magnitude in two different directions?
You see, as with many vector quantities, they are often displayed in their various components to simplify discussion. If we were to look at the resultant force curve (the curve created from the sum of Fz and Fy curves??? which is not displayed) we???d see something quite different. A quick look at the two curves and some basic graphical summation would quickly reveal that what you point to as the force peak would be quite different if we were looking at two directions (and even more so if we looked at all three directions). What???s my point? My point is that I can???t argue with someone who doesn???t understand that force application at ground contact occurs in all three planes.
[quote author=mike]I strongly disagree with Coach Ross???s contention that the direction of force application to the ground does not affect sprint performance.
Where did I say that? What was the context?[/quote]You have said it on numerous occasions and also imply it every time you say that technique doesn???t matter. Technique in flight influences ground contact position, which in turn affects the direction and magnitude of force application. The direction and magnitude of force application affects sprint performance.
[quote author=mike]I strongly disagree with Coach Ross???s conclusion that Weyand???s finding of insignificant difference in swing time across running speeds is equivalent to swing phase kinematics not mattering. This is flawed logic as Weyand only examined temporal kinematics and did not actually study the spatial kinematics of his participants.
Exactly what did I say regarding that? Show my quote that says exactly what you've posted. [/quote]
If what I said is wrong, how then do you come to the conclusion that swing phase kinematics are unimportant based on Weyand???s findings? He only looked at temporal parameters yet you say that all kinematics are unimportant???if what I said was untrue please explain how you came to your conclusions.
What I've said is that at ground contact, isometric force to offset gravity comes first, followed by an eccentric contraction. Oh, I also mentioned a "little shortening". I know that bugs you, but it's just taking up some of the slack in the tendon.
Again, Mike you ignore that giant spike in the force tracing. What is it? The eccentric contraction? You're imaginary huge concentric contraction at push off?
Force application is not necessarily indicative of muscle action. PERIOD. I???m not going to argue this one. You???re making ridiculous assumptions that would be laughed at in the research community (of which I am part of).
About you're theory of training altering kinematics, check this out:
THE INDEPENDENT EFFECTS OF GRAVITY AND INERTIA ON RUNNING MECHANICS
YOUNG-HUI CHANG, et al
"Subjects ran at 110, 120 and 130 % of normal weight and mass, at 110, 120 and 130 % of normal mass while maintaining 100 % normal weight, and at 25, 50 and 75% of normal weight while maintaining 100 % normal mass.
Only relatively small changes in running kinematics were observed across the three experimental treatments. Although the force magnitudes varied for each treatment, the orientation of the vectors remained nearly constant."
I???m sorry but I have to point out that you???re once again making conclusions from a research study about something that wasn???t studied. No technical intervention took place in the study. How can you then make comments on it? It???s just like you making wide-sweeping kinematic conclusions from Weyand???s research despite the fact that his group focused on kinetics.