In the afternoon the calf is very swollen and hard common causes are lumbar intervertebral disc herniation, lower extremity venous valve dysfunction and pear-shaped muscle syndrome. 1. Herniated lumbar intervertebral disc: it may be due to a large number of activities in the morning, resulting in the intervertebral disc to the spinal canal protruding even more, compression of the nerves innervating the lower limbs, causing vasospasm of the lower limbs, resulting in lower limb blood circulation disorders, the phenomenon of swelling and hardness of the calves in the afternoon. 2. Lower extremity venous valve dysfunction: when the lower extremity venous valve dysfunction occurs, the combination between the venous valves will be abnormal. If you stand for a long time during the day, resulting in increased pressure on the blood vessels, the blood will flow backward, which can cause the phenomenon of swollen and hardened calves. 3. Piriformis syndrome: If a patient with piriformis syndrome stands or walks for too long, the sciatic nerve will be more seriously compressed, which will lead to the phenomenon of very swollen and hard calves. Repeated calf is always very swollen and hard patients, should go to the hospital in time to identify the cause, so as not to delay the disease.