There are about 650 muscles in our body, and each one helps us in producing a movement. Physical exercise, training particularly resistance or weight training affects our muscular system to a great extent. They are as follows.
(a) Hypertrophy of the muscle: Due to resistance training the size of muscle fibres increases. Blood supply in the muscles increases. The total amount of proteins increases which is essential for muscle growth.
(b) Biochemical changes in muscles:
(i) Aerobic changes: Myocin content increases. Oxydation of carbohydrates and fats increases. Amount of mitochondria increases thus more muscular force is produced.
(ii) Anaerobic changes: ATP+PC system capacity increases, thereby more energy is released. Glycolytic capacity also increases as a result of training.
(c) Body composition changes: There can be significant losses of relative and absolute body fat. Fat free weight or muscle mass increases significantly. After training flexibility increases which plays an important role in physical activities to enhance the performance and prevent muscular injury.