Cramp, also known as tendon, is medically speaking supposed to be a phenomenon of muscle spasm, which is caused by irregular and irregular movement of muscles, and is an extremely common symptom in orthopedic clinics. The causes of cramps in the left leg are considered to be the following possibilities: First, after strenuous exercise, such as running, climbing, swimming, or after super-intensive physical labor, the muscles of the left leg can cause muscle spasm and cramps due to short-time ischemia and hypoxia; second, the left leg may feel wind chill or rheumatism, causing local tissue vascular spasm, resulting in tissue ischemia and hypoxia, thus producing cramps; third Calcium is a good neuroleptic, calcium deficiency causes abnormal nerve impulses in the nervous system, which in turn causes muscle cramps, the possibility of this situation accounts for a large proportion, you can go to the hospital to do blood calcium, free calcium and other aspects of the examination, and then give appropriate calcium supplements.