TRUE - Our body uses rest as a way of repairing any damage. For example, when someone goes on a 10km run, plenty of muscle fibres throughout the body have torn and become damaged. While this is nothing to be concerned about, it is a natural process, one must also give their bodies adequate rest in order for the muscle to repair. Not only does the muscle repair itself, but it adds a preventative measure to ensure that it does not tear as easily again, it then adds more muscle fibres. This is why we see people become more muscular, it is though a repetition of tear muscle fibre, eat and sleep and repair then repeat. Hope this helps!