Anaerobic Exercise: Exercise of much higher intensity than
aerobic work, which uses up oxygen more quickly than the body can
replenish it in the working muscles. Anaerobic exercise eventually
builds up a significant oxygen debt that forces an athlete to
terminate the exercise session rather quickly. Anaerobic exercise
(the kind of exercise to which bodybuilding training belongs) burns
up glycogen (muscle sugar) to supply its energy needs. Fast
sprinting is a typical anaerobic form of exercise.