The frontal muscle soreness of the thigh refers to the soreness of the quadriceps muscle, commonly due to the following reasons: 1, strain, due to long-term standing, walking, jumping or climbing, stairs and other activities that cause fatigue of the thigh muscle, long-term will cause strain, strain produced by aseptic inflammation, resulting in soreness. 2, the degeneration of the thigh muscle, such as long-term sitting in the office people do not exercise, or the natural atrophy of the muscle will increase in age. The quadriceps muscle strength decreases, when a little too much exercise or labor will produce an increase in lactic acid, lactic acid accumulation will produce soreness if not eliminated in a timely manner. 3, viral invasion, such as a cold when the virus invaded the body, resulting in muscle soreness reaction.