Calf pain, swelling and weakness may be related to trauma, lower extremity vascular lesions, knee joint lesions and other reasons. 1. Trauma: trauma causes soft tissue damage to the calf, capillary rupture and bleeding, there will be soreness and swelling of the calf, subcutaneous bruising and other symptoms. 2. Lower extremity vascular lesions: varicose veins and venous thrombosis in the lower extremities cause obstruction of venous return, which can also lead to symptoms of soreness and swelling of the calves. 3. Severe knee osteoarthritis: osteoarthritis, rheumatoid arthritis, excessive swelling of the joints with fluid accumulation will also cause symptoms of soreness, swelling and weakness of the calves. In addition to the above reasons, walking for too long, some internal diseases such as heart failure, chronic nephritis, etc. will also appear symptoms of calf swelling and weakness. If you have soreness, swelling and weakness of the calves, it is recommended to go to the hospital for medical examination and receive regular treatment.