The common reasons for the appearance of softness and weakness of the foot and neck are degenerative osteoarthritis of the ankle joint and acute sprain of the ankle joint, etc., as follows: First, degenerative osteoarthritis of the ankle joint: it is a chronic accumulative disease, patients usually have pain and weakness of the ankle joint, there will also be swelling of the joint and limited movement, etc. Taking X-ray films will reveal hardening of the joint surface, cystic lesions under the cartilage, and can even be found The joint space is obviously narrowed. Second, acute sprain of ankle joint: acute sprain of ankle joint can easily occur when going down the steps, resulting in swelling, tenderness and weakness of ankle joint, and manifesting as limited movement of ankle joint, even unable to walk and exercise with weight, which can be significantly relieved by cold compress treatment. After the patient has developed ankle joint tenderness and weakness, early diagnosis should be made to determine the cause of the disease, and treatment according to the cause can bring significant relief to the symptoms. In addition, you should pay attention to protecting the ankle joint and do more heel lifting exercises to enhance the stability of the ankle joint.