Stovepipe method: 1: Stand upright, with right foot in front and left foot behind. The left leg knee is slightly bent. Then do squats, pay attention to keep your balance when squatting. Repeat 3 groups 20 times on each side. Please sit on the floor with your feet together and your knees open. Keep your upper body straight and raise your hands horizontally forward. Then sit back on your hips. Group 3 repeats this action 20 times. 3: Stand straight, legs apart, shoulder width apart. Put a fitness stick on your shoulders with your hands (if not, cross your hands on your chest). Then squat down until your thighs are parallel to the ground. Group 3 repeats this action 20 times. 4: Please stand up straight with your legs together, hold the back of the chair, and then lift your left calf backward and upward to feel the force exerted by the muscles on the back of your thigh. Group 3 repeats this action 20 times.