The lack of strength in the left calf may be caused by muscle strain, neurogenic factors, vascular diseases and other reasons. 1. Muscle damage: due to the patient’s long-term exercise in the wrong way or chronic muscle strain and injury, cold and other causes of muscle aseptic inflammation, due to the accumulation of lactic acid, so it will cause muscle soreness and pain, it is recommended that the patient can lie down to rest and in the local hot compresses to increase blood circulation, to ease the pain. 2. Neurogenic factors: patients with lower limb nerve compression or inflammation stimulation and other neurogenic factors, can also be manifested as left calf pain, clinically seen in lumbar spondylolisthesis, disc herniation, spinal stenosis and other lumbar degenerative diseases. 3. Blood-borne diseases: if the patient for vascular muscle soreness, usually may be due to atherosclerotic occlusive vasculitis, arterial occlusive vasculitis, lower extremity saphenous varicose vein disease, this is due to the poor blood return or insufficient blood supply and caused by the pain. There may be other reasons for the pain in the left calf, it is recommended to go to the hospital in time, complete the examination to clarify the cause of the disease, and then give targeted treatment or therapy.