Basic Muscle Physiology: A Quick Review
Let’s review a little basic muscle physiology to understand WHY the concept of Time-Under-Load is so important.
And let’s keep it simple, shall we?
The smallest unit of a muscle is a motor unit. Motor units work much like a regular light switch – they are either on, or off. There’s no in-between.
There are very small motor units. And very large motor units. And medium-sized motor units. Your body will only use as many (and as large) as it needs to do work – to perform a certain task.
For example, say you reach down on your desk to pick up a pencil. Being very light, only the smallest motor units will kick on. And not very many of them.
If you squeezed that pencil very hard and tried to break it in half, more of the larger motor units would have to kick in and turn on in order for you to be able to generate more force. And if you continued to squeeze hard for more than a few seconds, eventually those smaller motor units that first turned on would become fatigued. They’d tire out.
So eventually more motor units would have to turn on in order for you to be able to continue to squeeze and generate the force required to break the pencil.
If you squeezed hard and long enough, you’d be getting really tired and your hands and fingers would start to hurt like hell! Even though you’d be feeling like the smaller muscles in your hands and fingers were exploding, the reality would be that they’d be generating less and less force as time went on, due to fatigue. That is, as you are getting increasingly tired and feeling quite a bit of significant discomfort, the actual amount of force you are generating is getting lower and lower. It doesn’t feel that way, I know!
Now imagine, instead of a pencil, you were bending over to pick up a much heavier steel rod. You’d need more of those motor units (and larger ones) to kick in and turn on.
Are you following me here?
Even more motor units and larger ones will have to kick on to contribute!
My friend, exercising doesn’t make us stronger.
What makes us stronger is STRESS to our body, which in turn causes an adaptive response to become stronger.
You get that positive stress that forces adaptation to a higher level of strength more efficiently – more quickly, with time under load. It’s that simple.
And again, not easy mind you. But it is simple.
Bodyweight training is NOT ABOUT using your muscles to move the weight of your body.
Rather, you should think of it as using your body weight to work your muscles harder.
Think about it!