Pain in the thigh muscle typically occurs the muscle has been strained, according to the American Academy of Orthopaedic Surgeons. Muscles in the thigh are strained when muscle fibers are torn or overstretched. A direct blow to muscles can also cause a strain or thigh pain.
Active individuals with poor conditioning or weak thigh muscles are at risk for a strain or thigh pain, states the AAOS. When thigh muscles are weak, they are less likely to withstand the stress of activity or exercise. Tightness within the thigh muscles can also make people prone to injury, resulting in pain. Fatigue within the thigh muscles makes the quadriceps and hamstring muscles more susceptible to injury, as the lack of energy cannot compete with the capabilities of the muscles.
When a muscle imbalance is present within the body, thigh pain is often a result, explains the AAOS. If a quadricep muscle is stronger than a hamstring, the weaker muscle becomes strained instead of both muscles working together equally.
Symptoms of a muscle strain in the thigh include sudden or severe pain in addition to a snapping or popping sensation, according to the AAOP. If blood vessels break, bruising may be visible on the thigh area.