1. Knee forward flexion
(1) Practice method: Sit at the front of a chair, straighten your knees and put a book of appropriate weight on your ankles. First, straighten your knees and lift them off the ground while keeping the books from falling. Hold for 10 seconds and then slowly bend your knees so that your heels lightly touch the ground and then slowly lift them up. Keep your knees straight for another 10 seconds. Repeat this, 6 to 10 times per group, 3 to 4 groups.
(2) Practice essentials: During practice, the muscles of the front thighs should be kept tense at all times and cannot be relaxed even when the knees are bent and the heels touch the ground lightly. The height of the chair must be no less than 60 cm, otherwise the knee joint flexion angle will not be enough to achieve the purpose of training.
2. Single-leg half squat
(1) Practice method: stand on a flat ground with one leg, bend the knee joint of the standing leg to 120 degrees as much as possible, and then straighten it knee joint. When straightening the knee joint, it is enough to be close to 180 degrees, not completely straight or hyperextended. Repeat this, 10 times per group, 3 to 4 groups.
(2) Practice essentials: During practice, the muscles of the front thighs remain tense at all times and cannot be relaxed even when the knee joint is straightened. When bending, the knee joint cannot be buckled inwards, otherwise tight outer thigh muscles may cause low back pain and other sports injuries. At no time should the knee joint go forward past the toes, otherwise excessive pressure on the patella may cause knee joint pain.
3. Lunge and Squat
(1) Practice method: Open your legs front and back, with the distance slightly larger than the normal stride length. Keep your upper body tall, chest up, abdomen in, and back tight, then slowly bend your knees to 90 degrees while maintaining balance, and then stand up slowly. Alternate legs, 40 steps per group, 3 to 4 groups a day.
(2) Practice essentials: Keep your upper body vertical and upward at all times, and do not lean forward or backward. The stride length should be moderate, too large or too small will affect the exercise effect.