May 25, 2016
Determinants of Strength Performance Part 1
In a long-ago written article (that was written while I was doing a lot of endurance training, go figure) I wrote about the primary determinants of endurance performance and today I want to do sort of the equivalent article to that for strength production (of no surprise, I’m doing mostly lifting now).
Now, if you want to get technical, you can define different kinds of strength. What is often measured in the lab is isometric strength using some kind of tensiometer (that will give you force output in Newtons, not the Fig kind, or whatever the units are) but in practical sense most will be more concerned with how much weight they are lifting in some gym movement. Even that can be subdivided and some folks might really get up their butts by worrying about concentric strength (how much weight can be lifted), isometric strength (how much weight can be held at some position in a movement) and eccentric strength (how much weight can be lowered under control).
The weights would go up from concentric to isometric to eccentric (i.e. you can lift less than you can hold and hold less than you can lower) but for the purposes of this article, I’m only going to worry about concentric strength. Most of what I will write still applies but there are some slight differences that I can’t be bothered to talk about. So concentric strength, how much weight can be lifted through the range of motion for some exercise is how I will define strength here.
Muscles, Bones and Force Production
Without getting into a big physics wank about the forces acting on the body let me talk briefly about how muscles generate force. Muscles are simply bundles of individual fibers that, when they contract, attempt to move the bones that they are attached to. By doing so they translate what is linear movement (muscles contract linearly) into rotational motion (all joints move in a rotational fashion).
So when the biceps contract in a straight line, they cause the forearm to curl upwards as it rotates around the elbow (I’m not getting here into torque, axis of rotation or lever arms here; at some point I want to do an overwritten series on that topic alone but this is not that time).