Cellular matter, much of it combinations of amino acids, slough off into the bloodstream under extreme stress. If not enough replacement protein is supplied through proper diet, the body will go into a catabolic state. In this state, the body literally feeds upon itself- its own protein structure- to meet the energy demand. As a result, the body loses muscle.
Muscle damage is the highest when you do ballistic and eccentric movements with major muscles. In weight training, this relates to the so-called "bounce" or "jerky" movements, and 'negative' (lowering of the weights) movement. These motions and their effects are usually exaggerated during heavy-duty bench press, squat, and pulling motions.
In order to prevent the effects of catabolism from negatively impacting the body, you must ensure proper protein supplementation. For an active adult, this usually equates to 1-1.5 grams of protein for every pound of lean body mass. This means you would figure your body fat percentage, multiply that number by your total weight, and then subtract the product from your total weight. For those who are extremely active, like athletes, the proper protein requirement would be closer to 2 grams per pound of lean body mass.
