How and why our muscles in our body grow can simply be viewed as our body’s way of “adapting” to tension. The general principle is relatively simple thinking about the intricacy of our muscle’s anatomy. When you exercise, for example as you lift weights, jog the mile, or perform any strenuous physical exercise, you will break down muscle tissue in the body. The a lot more you exercise the more muscle tissue will be broken down. When you take a rest after all those physical exercise and weight lifting, your entire body will try to rebuild the broken layers of tissue, but a little stronger than last time so the tissue will not break as easily as compared to before.