Sore leg muscles may be caused by lactic acid buildup, venous lesions, osteoporosis, lumbar spine disease, etc. Lactic acid buildup can be relieved by massage, while disease factors lead to little effect of massage. Sore leg muscles may be caused by the accumulation of lactic acid in the muscles after strenuous exercise and calf muscle strain. By massaging the leg muscles with appropriate strength, the local blood vessels in the leg muscles can be expanded to promote blood circulation and reduce the accumulation of lactic acid. It also relaxes the leg muscles and therefore relieves the symptoms of leg soreness. If leg muscle pain is caused by venous lesions, osteoporosis, lumbar spine disease, etc., it is recommended to go to a regular hospital to find out the cause through the lower limb vascular ultrasound and X-ray film of the lower limbs, etc., and to carry out treatment if necessary.