People with bad knees should not do deep squats because the load on the knee joint is very heavy, including the extrusion of bone, cartilage, wear and tear, as well as the stretching of the joint capsule and ligaments, and the force and load is very high, which can be several times the normal amount of load when standing and walking. Deep squat training for patients with bad knees can aggravate the damage to the knee joint and cause aggravation of the original knee joint disease. Patients with bad knee joints can perform functional exercises without weight on the knee joint, including swimming or lying on the bed or floor to perform the corresponding functional exercises of the knee joint, the main principle is to keep the knee joint without weight. The main principle is to keep the knee joint free of weight. Before performing the corresponding exercises, it is important to improve the diagnosis, to clarify what the knee joint disease is, to take the corresponding treatment measures to prevent further progress of the disease, and to take the corresponding functional training of the knee joint after the diagnosis is clear and the treatment is good.