The inability to lift the leg may be caused by overwork, varicose veins of the lower limb, nerve compression and other reasons. 1. Excessive exertion: Excessive exertion, such as walking too much in daily life or doing a lot of exercise, leads to excessive fatigue of the quadriceps muscle on the front side of the thigh, resulting in the inability to lift the leg. 2. Varicose veins of the lower limbs: patients with varicose veins of the lower limbs, resulting in obstacles to blood circulation in the lower limbs, which may lead to heavy legs, difficulty in walking, and inability to lift the legs. 3. Nerve compression: the nerves innervating the quadriceps muscle are damaged or compressed, resulting in the loss of innervation of the leg muscles, causing leg muscle weakness with symptoms of leg lifting. Myasthenia gravis, intracranial lesions and other causes can also lead to the emergence of leg lifting, if the leg lifting situation is serious, accompanied by other uncomfortable symptoms, should promptly ask the doctor to diagnose and correct treatment. Avoid over-exertion in daily life, which may cause discomfort.