After your workout it is vital to replace the glycogen which gives your muscles their lean mass and energy. According to current research, the protein requirement of athletes is approximately 1.2 - 1.8g/kg body weight, compared with 0.8 - 0.9g/kg body weight for less active individuals. For heavy athletes, this extra requirement is especially important.Studies have shown that the inclusion of protein in sports recovery drinks can improve recovery and reduce post exercise stress after strenuous training. Glycogen is the stored form of glucose which is used as an energy source in muscles. It is also the main component of lean muscle mass. Muscle glycogen can usually provide sufficient energy for about 45 minutes of high intensity exercise. Once these reserves are used up, muscles become fatigued and more sensitive to cramps. You must replace your muscle glycogen immediately after exercise to feel fit and be ready to exercise the following day.The rate of post exercise muscle glycogen synthesis is 40 - 50% faster with carbohydrate / protein mixtures compared with carbohydrate only drinks. The presence of protein appears to enhance insulin secretion primarily influenced by the carbohydrates, producing an increased rate of muscle glycogen synthesis.