However, lets see what bodybuilding authors like Sean Nalewanyj or The Musclehead, by taking those two names I mean those authors who have really good online bodybuilding programs, have to say about it.
In words of Sean Nalewanyj (Quoted From Truth About Building Muscles): "Highly intensive training places very large amounts of stress on your body and if you fail to give the muscles adequate time to recover and heal in between workouts you will end up doing yourself more harm than good.
In words of The Musclehead (Quoted From The Musclehead Guide To Godlike Physique): "your rest period should also be increased to however long you need to be able to lift at full strength again."
I hope that conveys the idea in quite a simple manner. Rest is as vital as workouts or diet, in no case should you neglect it or act as a miser when it comes to giving your body proper rest. Also when we say rest we don't mean the rest between sets or reps. Ideally you should be taking a week off after training for 8 weeks a part of recovery process.
First of all, this rest provides your joints and connective tissues the much-needed break. All of those sets taken to muscular failure will have a negative, cumulative effect on those delicate joints, and if you aren't careful you may end up with an injury. Among all the ways to prevent yourself from getting injured, taking proper rest is one of best ways.
Similarly, your immune system also gets a break.
Also taking a week off in between gives you a much needed mental break.It will not only increase your focus when you return but also help you put in more concentrated efforts.
If you wish to read more of such bodybuilding secrets, you can opt for their bodybuilding programs. You can read more on this musclehead review. Similarly you can use this link for more information on Muscle Gain Truth.
By the way, if you are already following a bodybuilding program then you can also use this free software for bodybuilding programs. It helps you keep track of your progress including "REST".