Lower extremity pain is considered to be caused by excessive exercise, lumbar spine disease, pyriformis syndrome, osteoporosis and other reasons. 1. Excessive exercise: after excessive exercise or overwork of the lower limbs, lactic acid accumulates in the muscles of the lower limbs, causing physiological soreness of the lower limbs, which can be relieved after resting. 2. Lumbar spine diseases: such as lumbar disc herniation, lumbar spinal stenosis, etc., when these lesions for the nerve root caused by compression, will cause lumbar pain and lower extremity radiating pain, numbness and other symptoms. 3. Piriformis syndrome: the sciatic nerve passes under the piriformis muscle, and the damage and inflammation of the piriformis muscle will cause compression and stimulation of the sciatic nerve, which will cause lower limb pain and numbness. 4. Osteoporosis: mostly seen in the elderly, there will be a decrease in the amount of bone and bone tissue microstructure damage, which will cause low back pain, and in severe cases, it will also involve a number of joints in the body, and lower limb pain. There are other causes of lower limb pain, such as trauma, arthritis, necrosis of the femoral head, etc. If the symptoms are serious or can not be relieved after resting, you can go to the hospital to further find out the cause of the disease, and then comply with the doctor’s instructions for targeted treatment, so as to avoid delaying the condition.