Calf muscle swelling and hardness consider muscle injury, lower extremity venous thrombosis, calcium deficiency, cold and other reasons. 1. Muscle injury: when the lower extremity calf injury will appear after the calf muscle swelling and hardness, need to rest for a few days, local cold compresses, external Yunnan Baiyao aerosol. 2. Lower extremity venous thrombosis: the formation of blood clots in the lower extremity blood vessels will cause local blood flow is not good, swelling, hardness, do lower extremity vascular ultrasound can be a clear diagnosis. 3. Calcium deficiency: leg cramps occur when there is a calcium deficiency, the calf will be swollen and hard, and the symptoms can be improved by calcium supplementation. 4. Cold: when the lower limbs after the cold will cause muscle spasms appear localized swelling and hardness, hot compresses after the symptoms can be reduced. There are many possible causes of calf muscle swelling and hardness, it is recommended to go to the hospital for further examination to clarify the cause of treatment.