Physical education: Physical education is a scientific method to enhance physical fitness and promote physical and mental health by consciously using the human body's own exercise according to the natural laws of human body's adaptation to changes, and it is a cultural and educational activity of society.
Fracture: Fracture refers to a disease in which part or all of the bones are broken due to trauma or pathological reasons.
Sports injuries: injuries that occur during sports are called sports injuries.
Gravity shock: At the end of a long period of strenuous exercise, if you suddenly stop and stay still, due to the disappearance of muscle pump and the effect of gravity, a large amount of venous blood will be deposited in the skeletal muscle of lower limbs, and the amount of blood flowing back to the heart will be reduced, the cardiac output will be correspondingly reduced, and the arterial blood pressure will drop rapidly, so that the brain will temporarily faint due to insufficient blood supply. This phenomenon is called gravity impact.