When a person starts to run and walk, creatine phosphate, which is ready and toxic, is used as a result, creatine is released and then creatine is excreted out of the body by the kidneys.

When the creatine phosphate substance is depleted, the muscles begin to use glucose. At this time, the motor end plate is stimulated by the acetylcholine substance in the muscle and the sarcoplasmic reticulum gives calcium to the sarcolemma. The calcium circulates around the actin and myosin proteins and they begin to prepare the contraction.

When the muscle contracts, the sarcomere length is shortened, the I band shortens, the H band disappears, The muscle volume does not change, the length of the muscle becomes shorter, the length of the A band does not change. When the contraction ends, the motor end plate is not stimulated by the muscle acetylcholine, and the calcium in the sarcolemma passes back to the sarcoplasmic reticulum and the contraction ceases. It is possible