This is what I call the recovery between sets. As you should be aware of by now, when training in an overload manner, Adenosine Tri-Phosphate (ATP) is our primary energy source. Between each set of maximum intensity, you need to recover for a minimum of 3 minutes. This enables a minimum if 90% ATP replenishment. Any less, and you greatly reduce your energy output. You can see now why training techniques such as drop-sets can be counter articleive.
This is what I call the recovery between training the same body part twice. You hear some people saying that it takes 48 hours for a body part to recover before you can train it again - what nonsense. If you train hard, you are nowhere near recovered by then. Plus, if you are recovered, what about the over-compensation? This is how it works.
When you train hard, after the workout you become sore. There have been a lot of theories behind Delayed Onset Muscle Soreness (DOMS), and the most respected is that during the lowering phase of the rep, tiny microscopic tears in the Sacromeres develop (little muscle tears). Now, you need to wait until these guys heal, and then they get a little stronger and bigger to handle that same stress again. Do you think this can all happen in 48 hours? Nope.
You need to wait a recommended 7 days before training the same body part again. In other words, if you train chest on Monday, wait until next Monday to train it again.
This is what I call it when you need to take an extended leave from the gym. Before you get all edgy over this, listen up. You need to schedule in periodic absences from the gym every 2-3 months to really benefit from all your hard work.
As we all know, intensity governs how hard a workout is. If we keep training day in and day out for months at a time, our intensity will drop, You might not realise it, but it most certainly does. By taking a week off every 10 weeks or so, this lets our body (both physically and mentally) recharge, and when we come back to training we are once again performing at 110%. There is no point training at 90% when it takes a 100% commitment to change your physique. For that week off, kick back and do as little as possible. Let your body take advantage of this time-out period, your goals will be better for it.
There you have it. You can now see how recovery varies, and to appreciate how important recovery is to your physique goals. Don't neglect recovery, because if you do the only person who will be effected is yourself.