Re: An exercise that illustrates internal power
A necessary hypothetical question to ask: why would one want to do all the work with their abdomen?
Imagine the body standing up. It's a (vertical in this case) line. Look at all the musculature along its length. Now, if you were to pick any muscle along that line, and have it try to move the entire body, then you are pitting the strength of one single muscle (say, the hip flexor) against all the rest of the body. Almost the entirety of your body above some particular muscle is dead, non-functional/non-contributing weight, and anything below it is non-functional/non-contributing as well. If you short-circuit any part of the line, trying to express force through somewhere closer, to the particular muscle you have singled out, then you may remove the non-functional weight, but you also remove any potential assistance from the rest of it too.
Now take that same situation, but start with every major joint in the body bent, and then have it all extend at the same instant back into that line. In that case, you're using the entire power the body can bring to bear to express a force along that line. "If one part moves, all parts move" - the unity of movement in the body is so ingrained that all parts are moving in any given movement - there are no breaks in the movement at any part of the body.
Taking your example. Rest one your other forearm on top of the fingers. Now straighten the wrist... Fingers collapse.
Try it again with fingers tensed into a straight line. You now have a solid lever to lift your other forearm with.
Now, start this time with fingers relaxed again. But straighten both the fingers and the wrists at the same time.
Or to make the effect more obvious: extend your arm from shoulder to finger tips into a straight line. Again rest your other forearm on top of the fingers. Now try to lift your other forearm by merely extending that unit at the shoulder. A lot of work for the shoulder.
Try it again but this time lifting with all the other joints to (bending the elbow joint, extending the fingers and wrist).
Or to make this even more obvious (with two different lever arms, but different amount of muscle participation):
Start with the elbow joint entirely bent, so you can rest your other arm directly on top of the elbow. Now lift that arm by merely lifting the elbow up with the shoulder.
Extend that arm out again (elbow joint no longer bent) so you now have a huge lever again, and rest your other arm on top of the wrist joint. Now lift at the shoulder AND bend the elbow joint. It's still easier.
Last edited by Lee Salzman : 10-24-2007 at 12:36 PM.