The supine leg raise is not harmful to the lumbar spine, but it is not recommended if the patient is currently suffering from a lumbar spine related condition. The supine leg raise is a very good exercise for lower extremity muscle strength. This exercise is suitable for patients who are currently not able to move down to the ground to bear weight, but need to strengthen the muscles of the lower limbs in preparation for future weight bearing. The supine leg raise requires the patient to straighten the knee joint, then slowly raise the lower extremity and then slowly lower it, which can effectively strengthen the muscles of the lower extremity. But if the patient is currently suffering from lumbar spine related diseases, such as the existence of severe lumbar disc herniation, or compression fractures of the lumbar spine, or a series of lumbar vertebral slippage and so on, then it is not suitable to do such activities. Because in the process of supine leg raising, it may aggravate the instability of the lumbar spine, or induce fatigue of the lumbar abdominal muscles, and therefore is not conducive to the recovery of the above-mentioned diseases. In addition, patients can do such functional exercises under the guidance of a doctor to enhance the muscle strength of the lower limbs.