Pain in the patellofemoral joint or patella is common and can be caused by a variety of factors, but the most common is an abnormality in the patella’s gliding path. Abnormal patellar glide trajectory can often be caused by a tight lateral patellar support band or an abnormal knee force line, which makes it difficult for the medial femoral muscles to maintain the patella in its normal position. The following exercises can be performed regularly to strengthen your medial femoral muscles and restore the patella to its normal position. Sitting training Thigh flexion 45 degrees of external rotation position (with a pillow or towel roll pad again behind the knee), put enough weight on the ankle joint (such as sandbags), force contraction of the inner thigh muscles, overcome the weight of the ankle joint to extend the knee, but do not lift the foot. Put your hand on the inner thigh to feel the muscle contraction, but relax the other thigh muscles. Contraction held for 10 seconds, relax for a few seconds, repeat the training content for 10 minutes. 3 to 4 times a day. Concentrate on training and do not do other things at the same time (such as watching TV). Standing training Keep your feet one foot wide, do a lunge so that the second toe, heel and patella are on the same vertical line, contract the inner thigh muscles with force, but relax the outer and rear thigh muscles. Contraction is held for 10 seconds, relax for a few seconds, and repeat the training content for 10 minutes. 3 to 4 times a day. Walking training Walk with the affected limb in front, shift the weight to the affected limb, make the medial femoral muscle contract, slightly externally rotate the knee joint, and shift the weight to the lateral side of the affected foot, keep the contracted medial femoral muscle of the affected limb to step out of the lower limb on the healthy side, repeat the training. Step training Use a small bench as a step, the affected foot stands on the step, the center of gravity is located slightly lateral to the affected foot, the knee joint is located directly above the affected foot, ascend the step, the medial femoral muscle contraction to maintain the smooth movement of the knee joint, and then cross the step while maintaining tension in the medial femoral muscle. Gradually increase the step as the exercise progresses.