Knee quadriceps exercise method: 1, sitting will be straight knee relaxed, toes up; 2, tense knee, raise the entire lower limb, to and seat parallel instantly, maintain 10 seconds; 3, relax, rest five seconds; 4, repeat the above actions, each time do more than 10 movements; 5, 20 times a day, adhere to a week. During this week, walk less on the ground, do not go up and down stairs, do not do squatting movements. Objective: To maintain the patella on the normal patellar trajectory and make the patellofemoral joint more compatible. Suitable patients: elderly patellofemoral arthritis (mainly manifested as inability to squat, go up and down stairs, knee swelling), patellofemoral joint disorder (pain, swelling and femoral condyle cartilage damage after climbing in young people), rheumatoid knee arthritis attack period.