When running, every step, the knee will bear 7 times the weight of the pressure, quadriceps femoris 4 times the weight of the pressure, the sole of the foot bear 3 times the weight of the pressure. Yang Shimiao, associate professor of Rehabilitation Therapy Science at Hong Kong Polytechnic University and vice chairman of Hong Kong Amateur Track and Field Federation, pointed out that knees move forward normally during running, patella and femur contact surface is the largest and strength can be evenly distributed, but if the posture is wrong, especially in pursuit of speed, it will increase joint pressure, even make patella valgus or internal rotation, and accelerate cartilage wear on contact surface. This will not only affect the future running, even walking, up and down stairs are a problem. Error posture: 1. lean backward, more effort when striding forward; 2. heel landing, the whole leg in a straight line, to increase knee impact strength, 2. unable to mobilize thigh muscles to share weight, disguised increase knee pressure; 3. stride, the body center of gravity is far from the supporting foot, quadriceps femoris need to use greater force to maintain body balance, increase patellofemoral joint tension. Correct posture: 1. Body forward tilt, to provide power for forward, more labor-saving; 2. Knee forward bend, facilitate the mobilization of thigh muscles, sharing pressure, and play a buffer role, while increasing patellofemoral joint contact area, conducive to the average distribution of pressure, reduce friction; 3. trot, so that the body's center of gravity closer to the supporting foot, quadriceps femoris can maintain body balance without too much effort. The patellofemoral joint was slightly pulled.