Feeling the muscles of the lower limbs are hard and heavy, there are several common reasons: First, the muscles of the lower limbs of the long-term chronic strain or acute injury after poor recovery, resulting in the muscle fibers continue to be congested, edema, or even including inflammatory infiltration, scar contracture and local necrosis, resulting in the tension of the muscle fibers, resulting in the feeling of hardness of the lower limbs. Second, lumbar spine disease, due to lumbar spine disease caused by lower extremity sciatic nerve root compression, resulting in lower extremity neuromuscular function abnormality, resulting in localized hard sensation. Third, muscle hypertrophy of the lower limbs, muscle hypertrophy can be seen in physiological muscle hypertrophy, but also due to other causes of pathological muscle hypertrophy, such as hypothyroidism, local soft tissue infections, tumors, or congenital developmental abnormalities, can cause local muscle hypertrophy, resulting in muscle stiffness and decreased function of the symptoms.