Muscle training: physiology and practical applications of training for strength versus endurance.

An understanding of the physiology of muscle training can help the athlete, trainer, or therapist make specific improvements in athletic performance. Different metabolic pathways of muscle contraction predominate depending upon the type of work performed. Two anaerobic pathways provide energy for fast, powerful contractions while aerobic metabolism fuels sustained muscular endurance activities. Two types of human muscle fibers have been identified. Selective training of the different muscle fiber types can enhance performance in a particular sport.