Ever ask yourself why a gym is stocked with weights?
There is a very good reason for it and when you fully understand the reason your training takes on new clarity. We lift weights to build muscles – but why are the weights even necessary? Well, suppose you want to build up your biceps. Why not just sit watching TV and flex your empty arm up and down a thousand times while watching Boardwalk Empire? Hey, a thousand reps has to build some muscle, right? Nope. It probably won’t add a gram of mass to your biceps.
The way muscle is stimulated to grow is by being forced to work at or near the limits of its ability. We have to load the muscle with work. We no longer roll giant boulders away from our doorway or drag a heavy deer back to the cave to naturally build our muscles throughout our lives. We drive cars with power steering and drop our food into a shopping cart, so we need an artificial means to create heavy, strenuous work. A gym is filled with artificial loads to make that possible.
Ever since 1687 and our friend Isaac Newton we’ve known that the quantities involved in lifting can be exactly measure. In our case we want to know the amount of weight lifted per unit of time; say, lbs per minute, or kilos per second. The guy watching TV lifts a very small weight and it takes him hours to complete his exercise to exhaustion. A man in a gym can pick up a very heavy dumbbell and in seconds his biceps is completely exhausted.
But Wait, There’s More . . .
The problem is that gyms have a variety of weights and it can lead to thinking that one is basically as good as another since lifting something is better than lifting nothing. But not only are the weights not equal, the loads they deliver are wildly unequal!
Let me ask you this, if you lift 50% of your maximum weight do you think it will deliver 50% of your maximum intensity? Sounds logical, right?
We tested this.
We measured a group of men on the bench press. We tested how heavy a weight they could hold statically for five seconds. Then we tested how long they could hold lighter weights. See that chart below? When the weight was about half their maximum they could hold that weight 12 times longer! Do you know what that does to the weight/time calculation of intensity? It delivers 5% of the maximum. Five percent!
Even a cave man didn’t get stronger when he dragged home a rabbit instead of a deer. The same goes for us. Working at a small fraction of peak output will not stimulate new muscle growth.
So why are the lighter weights in the gym? Well, they are there for someone who isn’t you. The ‘light’ weights are there for the 90-lb woman or the young teenager for whom your ‘light’ weight is the absolute max they can lift.
One Final Note
Never listen to the old bromide about ‘light weights for definition, heavy weights for mass.’ A muscle can do three things: get bigger, get smaller or stay the same size. If you can’t see a muscle (low definition) that muscle needs to be bigger or the fat around it needs to go away and likely a bit of both. There are no ‘definition’ exercises or special weights for increasing muscle definition. Bigger, smaller or same size, which do you want? If you want bigger muscles you have to force them to grow and that means making them perform a great amount of work per unit of time. So do you want 100% intensity or 5% intensity?
The saying should be, ‘heavy weights for bigger muscles, light weights to waste time.’