The symptoms of knee and rear tendon pain after fitness, common causes are the following: 1, due to the corresponding overload in the fitness movement, resulting in soft tissue strains, including muscles, fascia, ligaments, joint capsule and other soft tissues, resulting in local bleeding, hematoma compression and congestion, edema and other pathological changes, resulting in the corresponding pain symptoms. This injury requires rest and can be quickly relieved. 2, seen in the fitness time due to the relatively large amount of exercise, local muscles, soft tissues and other increased oxygen consumption, the relative lack of blood supply, easily lead to local anaerobic metabolism, anaerobic metabolism products are mainly lactic acid, creatine, these metabolites will stimulate local pain symptoms. It is recommended that patients can adjust the amount of exercise, time and corresponding rest for observation, if the symptoms are not relieved, promptly go to the hospital for medical consultation.