Anabolism - catabolism

Through the time of practice the muscular tissues are overcast maximally. They need energy for its activity which they derive from accessible sources at that moment (carbohydrates, fats) If all sources are slacked, the body produces energy from muscular proteins what causes the loss and deficit of active muscular mass.

This process is called CATABOLISM

A supplementation of amino acids before practicing avoids destruction of muscular mass, muscular cells get a sufficient energy for an active muscular work.
Providing the sufficient amount carbohydrates after the practice, the regeneration of muscular tissue accelerates. A size of muscular cell enhances and grows of muscular mass accelerates.