Sitting for a long time to get up on the knee pain can be caused by physiological factors, may also be caused by pathological factors, such as meniscus or ligament damage, knee degenerative disease. 1. Physiological factors: the knee joint is in flexion when people sit, long time to keep the state of flexion, the local muscles and nerves for a long time by the external pull, in a state of tension or spasm, change the posture will appear when the knee pain, as well as the feeling of not being able to exert oneself. 2. Meniscus or ligament injury: meniscus and ligaments of the knee joint play a role in stabilizing the knee joint and protecting the joint surface. When trauma causes meniscus and ligament injury of the knee joint, it can cause instability of the joint and friction stimulation of the joint surface, which can lead to pain in the knee when you stand up and can not make strength. 3. Degenerative lesions of the knee joint: such as knee osteoarthritis, osteomalacia of the knee joint and so on. These lesions tend to compress the nerves and blood vessels around the knee joint, so that the surrounding soft tissue is damaged, the joint plane wear and tear, resulting in knee pain when you stand up to make the effort. Sitting for a long time to get up on the knee pain to make strength may have other reasons, if the symptoms continue or aggravated, we recommend that patients go to the hospital in time, clear cause for targeted treatment.