No exercise but thighs appear sore, the common reasons are the following: First, chronic strain, although there is no acute, strenuous large load of activity, long-term standing, walking or the nature of the work, resulting in chronic muscle strain, will also appear sore symptoms. Second, the sciatic nerve is affected, such as lumbar disc herniation or pear-shaped muscle syndrome leads to compression of the sciatic nerve in the lower extremities, the corresponding innervation area appears sore symptoms. Third, the stimulation of adverse factors, such as cold, moisture and other local muscles, blood circulation is affected, the accumulation of metabolic products appear soreness. Fourth, the presence of digestive system diseases, kidney system diseases, resulting in abnormal water and sodium metabolism or calcium and phosphorus metabolism in the body, the body’s calcium deficiency or water and sodium retention may affect the function of the nerves in the lower limbs, resulting in soreness of the thighs.