Visual detection of unwanted tension

From Biomch-W

1 Hypothesis
2 Rationale
3 Experiment required
4 Further discussion
5 Results
6 More information

Hypothesis

Unwanted tension in a sports action that has an approach-impact-follow through-return sequence, can be determined by visual detection of disruption to the return of body segments from follow through extreme positions back to neutral positions. Disruption includes a reduction in the magnitude of return and/or a pause at the extreme position before the return happens.

Definitions:

Unwanted tension: co-activation of opposing muscles that reduces the performance of an action.
Neutral position: generally mid-point angle around a joint (although potentially altered by circumstance such as gravity)
Extreme position: significant non-neutral angle around a joint such has prontated, flexed, etc...
Approach: movement towards impact, before impact.
Impact: any important impact such as racket/projectile collision.
Follow through: the consequential post-impact movement that is the result of the velocity at impact.
Return: follow through will typically bring some body segements into extreme positions. Because of the elastic nature of the muscles, under low activation conditions the joint should return smoothly to the neutral position (with minor oscillation).

[edit]

Rationale

I came up with this theory while examining the Badminton smash action. It seemed to me (through experiments on myself) that if I was physically tense, the return from extreme positions was severely restricted. If this theory could be validated then it would allow an extremely useful tool for coaches: by visually analysing the return, a judgement could be made on the amount of unwanted tension in the action. This would be useful because the unwanted tension (opposing coactivation) obviously results in a drop in performance such as impact speed.

[edit]

Experiment required

For validation or rejection it would be useful to compare EMG activity with motion data and see if there is a significant correlation with opposing coactivation and disruption to the return motion.

[edit]