T Nation

Maximal Voluntary Contractions


#1

I looked it up and from what I found talking about it is the same as talking about percentages of your 1RM.

Is this correct? I could find a clear explenation of the term and how it applies to training.


#2

You are right. A maximal voluntary contraction is essentially your 1RM. An involuntary contraction makes use of the stretch-shortening cycle and the reflexive properties of your connective tissue (tendons, etc.).

An example of this occurs in sprinting. Elite sprinters absorb impact forces off up to 5 times their body weight (I think I am recalling that fact correctly) on one leg during top speed. Obvioiusly they wouldn't have a chance in hell of 1-legged squatting 1000 pounds!

They are able to absorb this because of their incredible reflexive and elastic abilities. That's the difference between maximal voluntary and maximal involuntary.

I think I read that part of Supertrianing right??


#3

Can you explain the stretch shortening cycle, I would read up on it but I am up to my ears in reading for class that I have to do, so if you could give me a quick low-down that would be great. Thank you.


#4

MVC refers to the max level of force you can produce on your own. Usually this is measured isometrically (pushing against an imovable object). A 1RM is sorta a MVC, but in reality the force exerted by the muscle will change during the movement. An involuntary contraction would be more along the lines of electrical stimulation. Rather than you personally contracting the muscle, you send an electrical current to the muscle which causes it to contract.


#5

The stretch-shortening cycle is the process in which elastic energy is stored and used as output in a subsequent muscle contraction.

Here is an easy way to think about it. Squat down, pause for 3 seconds, then jump up as high as you can. Now do the same thing but descend quickly and don't pause at the bottom. Your jump will be higher because you made use of the stored energy in the countermovement.

Sk- I didn't even think about electrical stimulation, that probably makes more sense than my answer.