Severe leg soreness may be caused by strenuous exercise, lumbar disc herniation, varicose veins of the lower extremities and other factors. 1. Strenuous exercise: usually not much exercise, suddenly climbing, long-distance running and other strenuous exercise, may produce a large amount of lactic acid accumulation in the leg muscles, thus appearing in the legs severe soreness of the symptoms, usually rest for 3 to 5 days, can be gradually relieved. 2. Lumbar disc herniation: When lumbar disc herniation occurs, it may compress the nerves that innervate the lower limbs, which may lead to symptoms such as radiating pain, numbness, soreness and swelling in legs. 3. Varicose veins of the lower limbs: the blood flow rate in varicose veins of the lower limbs is slow and the blood vessels of the legs are tortuous, which may lead to the stagnation of blood flow in the parts of the legs, which cannot be well circulated, thus leading to the symptoms of severe soreness and swelling of the legs. If the patient with severe soreness in both legs does not perform strenuous exercise, he should go to the hospital in time for relevant examinations to clarify the cause of the disease before further treatment, so as not to delay the condition.