There are three steps to achieving muscle growth. The first step is you going to the gym and you train which breaks the muscle down.
Once you’ve broken down the muscle, your body is depleted of nutrients. So the second step, right after training, is to get in your protein shake or a meal so the recovery process can begin.
The last step is rest. Your muscles don’t grow in the gym they break down. So once you’ve done that and you’ve eaten the last step is to rest. It is during the rest process that your muscles think to themselves that they must grow back stronger and bigger so they can avoid being broken down in the gym next time.
Sam Johnson, NASM CPT