Since muscles grow when they are resting, has anyone got any tips, supplements or anything at all that will help my muscles grow more effectively during resting period?
Your supplements are called copious sleep, hydration (with milk if it's part of your diet, water if not), and food. You know--eggs, vegetables, olive oil, meat, butter, greens, starches.
Olympic lifting coach Greg Everett recommends walking, massage, self-myofascial release, and hot baths on rest days as well.
Beyond those, supplements are good primarily to make your wallet lighter, and thus easier to carry.
Sleeping over 10 hours a night improved athletic performance. To quote Mah, Mah, Kezirian and Dement:
Sometimes a very light workout is useful during a recovery day, but one's capacity for active rest intensity varies person-to-person, again according to Greg Everett:
If we want to grow muscle, we need to give it a reason to grow.
This reason (ie the stimulus) can be a 185 lb bench press or a 400 lb bench press - it all depends on the person.
If the stimulus is not enough, we will not grow. If it is too much, we will not grow either. If it is just right, however, and we allow for proper recovery (sleep + nutrients), we will grow.
Make sure you are challenging yourself but no over doing it. When in doubt, keep the gas tank filled to 10-20%. Leave the gym stimulated; not annihilated.
Now we can be giving our body the right stimulus (ie right amount of training volume) but still not be growing.
What's up with that?
Well, exercise is stressful for the body. And depending on our overall stress load, it can be good or bad.
When we sleep 5 hours, spend the day drinking coffee, and then decide to do a 1.5 hr training session - this is BAD.
There is just too much stress for our body to develop a positive adaption.
In most cases, when people are not building muscle as fast as they want, they need to learn to manage all the stress outside the weight room so that body can focus on adapting to that one stressor (ie muscle damage).
So how to quiet all the other stress?
1) Provide an acute stressor (exercise)
2) Cut down on all chronic stressors
3) Sit back and grow