This is part 1 of a 2 part chapter on anaerobic training. Anaerobic training is important for mid-life athletes to combat muscle loss, strength loss, and loss of power as they age. It involves high-intensity, intermittent bouts of exercise that require the regeneration of ATP at a much faster rate than aerobic exercise. Anaerobic training uses the phosphagen and glycolytic system, while the aerobic system is involved in the recovery of energy stores and the expulsion of metabolic wastes dur...