What really happens when we tighten our muscles?

[Skhandelwal]

I play ping pong and I was wondering if it bad for my health if I grip my racket as tight as I can all the time. I was wondering what biologically goes on when I tighten my muscles?

Thx.

 

[jim mcnamara]

To answer your implied question: keeping muscles taut usually does less damage to the muscle than it does to connective tissue - tendons, ligaments, and their friends.

A simple model of muscle contraction( all muscles work by contraction) is
to think of small bundles of fibers that can relax and lengthen when any external force is applied ( like your arm going straight down your side when you relax all the muscles in it. Gravity is the external force in this example).

When the fibers are excited by neurons, they shorten. They resist being stretched. The more fibers that contract, the stronger the pull they extert. To do this the muscle burns energy. If the muscle tissue is used to a lot of exercise the "burning" tends to be more aerobic, more efficient. If the muscle is not used to exercise or is over-exterting, the buring is anaerobic and results in the buildup of byproducts like lactic aicd - one cause of sore muscles after over-exertion.

 

[Danger]

The exact process of muscle contraction is fairly complicated, but it's essentially like a bunch of scales or shingles that slide over each other. You could sort of think of it like a series of linear-induction motors stacked up so that the armature of one carries the field coils for the next. Or, if you prefer, look at how a radio antenna telescopes in and out, then envision it as flat rather than cylindrical.
Gripping something tighter will reduce the length of time that you can hold it, since the lactic acid and other fatigue poisons will accumulate faster. Your wrist might get stronger all of the time, since muscles grow by being damaged and then repairing themselves to be bigger. There's also the possibility, I suppose, of developing carpal tunnel syndrome, but I think that's more caused by repetive motion rather than tension.
I would think, having played the game in my youth, that the worst thing about gripping as hard as you can would be the reduction of flexibility in handling the paddle. You'd probably have better control and speed with a firm, yet moderate, pressure.

edit: Oops; just saw your post, Jim. Good one.