The causes of muscle expansion and enlargement are divided into physiological and pathological causes. Physiological causes are due to the influence of genetic factors, nutritional intake in diet, habitual movements in life, study and work, and exercise habits as we grow older, so that the muscle shape grows and expands, thus adapting to our usual limb activities and body development needs. The pathological reasons are mostly caused by muscle damage or muscle lesions, when we accidentally hit or strain the muscle tissue in a certain location, the force is relatively large, the damage is more serious, it will cause a large local muscle tear, resulting in injury bleeding, exuding fluid. When the amount of exudate is relatively large, it will cause the expansion of the muscle to become larger, there will also be local pain symptoms, limb movement is restricted symptoms.