There are 639 muscles in the human body, each comprising around ten million muscle cells. Each of these cells is like a motor containing ten cylinders arranged in a row. The cylinders are tiny boxes that contain fluid and when a muscle contracts, the brain sends a message to these tiny boxes. For a fraction of a second, the fluid in the tiny box congeals , then it becomes fluid again. It is this action that causes the muscle to move.
When a muscle is stimulated into action, it reacts quickly – it may contract in less than one tenth of a second. But before it has time to relax, another message comes along. It contracts again and again. All these contractions take place so quickly that they become fused into one action with the result that the muscle performs one smooth – continuous action.
