Soreness in one calf may be caused by excessive exercise, or it may be caused by lumbar disc herniation, deep vein thrombosis of the lower extremities and other diseases. 1. Excessive exercise: such as standing on one leg for a long time or exercising on one leg for a long time, which can cause accumulation of lactic acid or muscle spasm, thus leading to soreness in one calf. 2. Lumbar disc herniation: refers to degenerative changes in the lumbar intervertebral disc or trauma caused by fibrous ring rupture, the nucleus pulposus prolapses from the rupture. If it presses on the spinal cord, nerves and blood vessels, it can cause lumbar pain, numbness, pain and discomfort in the lower limbs, thus causing a calf soreness. 3. Deep Vein Thrombosis of Lower Extremity: It refers to the formation of blood clot in the deep veins of lower extremity. The main manifestations are swelling and pain in the limbs, pressure and pain in the muscles at the back of the calf, the root of the thigh and the area through which the vein flows, which may be accompanied by elevated skin temperature, erythema and other symptoms. It can also cause soreness in one calf. There are many other causes of soreness and swelling of one calf, which should be taken seriously, and timely consultation should be made to identify the cause of the disease and follow the medical advice for further treatment or therapy.