Hard tight calves may be caused by overwork, but also may be caused by calf muscle spasm, lumbar disc herniation and other diseases. 1. Overwork: activities such as standing for a long time, running for a long time, playing soccer, working out, etc., can cause the muscles in the calf area to become strained, which can lead to hard and tight calves. 2. Calf muscle spasm: it is a kind of spontaneous tonic contraction of muscles, mostly caused by calcium deficiency, local neurovascular pressure, etc. It is mainly manifested as spontaneous tonic contraction of muscles, which can be accompanied by severe pain, and it can also lead to hard tightness of calves. 3. Lumbar intervertebral disc herniation: a common clinical disease, mainly manifested as lumbar pain, if the compression of the nerve, can cause radiating pain in the lower limbs, pain radiating from the lumbar region to the posterior part of the buttocks, the posterior lateral thighs, calves to the feet, can be accompanied by numbness, incontinence, etc., may also lead to the calf hard tightness. There are many other causes of hard tightness in the calves, which should be taken seriously, timely consultation, identification of the cause of the disease, and follow the doctor’s instructions for further treatment or therapy.