Sore legs can be caused by a variety of reasons, such as: strain injury to the muscles of the lower limbs, poor blood flow, neurogenic diseases of the lumbar spine, vascular diseases of the lower limbs and osteoporosis. 1. Lower extremity muscle strain injury: this aspect of the factors are mainly related to the accumulation of lactic acid caused by excessive exercise, high-intensity aerobic exercise will be insufficient intake of oxygen, lactic acid can not be decomposed into water and carbon dioxide in time, but in the muscle accumulation, the accumulation of lactic acid for a long time will cause localized soreness. 2. Poor blood flow: Commonly found in sedentary or standing people, poor blood circulation in the lower limbs or incomplete closure of the lower limb vascular valves, resulting in blood stagnation caused by leg pain. 3. Neurogenic diseases of the lumbar spine: such as lumbar spinal stenosis, lumbar intervertebral disc herniation, lumbar spondylolisthesis, etc., which can easily lead to stimulation or damage of the nerves innervating the lower limbs, thus inducing the soreness of the lower limbs. 4. Diseases of vascular origin of lower limbs: due to varicose veins of saphenous veins of legs, thrombosis of deep veins and other factors, the venous return of legs is obstructed, and the function of muscles and nerves of lower limbs is abnormal, thus causing leg soreness. 5. Osteoporosis: Commonly found in middle-aged and old people, the lack of calcium in the body causes osteoporosis, leading to muscle relaxation, which cannot support normal walking, and the load on the legs is increased, resulting in weakness, leg soreness and other symptoms. In addition, including such diseases as vasculitis, hyperlipidemia and other diseases can also lead to leg soreness, and it is recommended that patients go to the hospital for examination in time.