Muscle Hypertrophy
Muscle hypertrophy refers to muscle growth which is an increase in the size of muscle cells, also known as "bulking up" or "gains" (see Diagram 1). This occurs as a result of strength or resistance training that stimulates activity in muscle fibres causing them to grow. Hypertrophy does not occur as a result of aerobic training.
Muscle fibres enlarge after training. Reasons for this increase in size include the higher proportion of myofibrils (the contractile element of the muscles). The fibres also enlarge as a result of increased stores of glycogen and the energy-supplying compounds (ATP and phosphocreatine - PC) needed for the increased muscle size. Anaerobic training is more efficient at increasing muscle size whereas endurance training will not increase muscle size, it just burns fat, which makes the muscle more visible.
Training needs to follow the overload principle (see Diagram 2) to bring about muscle hypertrophy. Muscle hypertrophy occurs when an athlete lifts medium to heavy weights, such as training for strength, power or a lean body mass. Training for muscular endurance (lifting light weights with high repetitions) does not bring about a hypertrophic response. The heavier weights being lifted produce an overload response where the muscles enlarge so that during the following training session they are better prepared for the task.
As with other adaptations that occur as a result of training, the principle of progressive overload sees hypertrophy responses over a period of time. The principle of reversibility can be seen through muscular atrophy, where an athlete looses muscle size due to a lack of training.
Muscle fibres enlarge after training. Reasons for this increase in size include the higher proportion of myofibrils (the contractile element of the muscles). The fibres also enlarge as a result of increased stores of glycogen and the energy-supplying compounds (ATP and phosphocreatine - PC) needed for the increased muscle size. Anaerobic training is more efficient at increasing muscle size whereas endurance training will not increase muscle size, it just burns fat, which makes the muscle more visible.
Training needs to follow the overload principle (see Diagram 2) to bring about muscle hypertrophy. Muscle hypertrophy occurs when an athlete lifts medium to heavy weights, such as training for strength, power or a lean body mass. Training for muscular endurance (lifting light weights with high repetitions) does not bring about a hypertrophic response. The heavier weights being lifted produce an overload response where the muscles enlarge so that during the following training session they are better prepared for the task.
As with other adaptations that occur as a result of training, the principle of progressive overload sees hypertrophy responses over a period of time. The principle of reversibility can be seen through muscular atrophy, where an athlete looses muscle size due to a lack of training.