1. Isometric Balance Half-Squat: Stand upright, chest out and head up, feet shoulder-width apart with toes pointing forward. Slowly squat until you feel a slight soreness or tightness in the knee joint (the standard angle is 135 degrees between the back of the thighs, but adjust according to your own condition), then hold the position without moving until you feel obvious trembling from the soreness in both legs. After standing up, walk slowly to relax. Perform 3 repetitions per set, with a 1-minute interval between sets.
2. Isometric Back-Leaning Half-Squat: Stand upright with your back against a wall (or any stable surface), chest out and head up, feet shoulder-width apart with toes pointing forward. Slowly squat while keeping your back in contact with the wall — do not let it come away. Stop when you feel a slight soreness or tightness in the knee joint (the angle behind the thighs should not be less than 90 degrees, but adjust according to your own condition), and hold until you feel obvious trembling from the soreness in both legs. After standing up, walk slowly to relax. Perform 3 repetitions per set, with a 1-minute interval between sets.
Important Note: This exercise helps to unblock and regulate the overall function of the knee joints and specifically strengthens the quadriceps muscles around the knees. It is very effective in rehabilitating injuries to the knee joints as well as surrounding muscles and ligaments. Stay focused during the movements, keep your actions natural, relaxed, and precise. Perform one set each in the morning, afternoon, and evening every day — the benefits will become evident over time.