Background
The thigh is the bulkiest region of the lower limb and comprises the powerful hamstring and quadriceps muscle groups and important nerves such as the sciatic and femoral as they pass down the lower limb.

Common Injuries
Hamstring muscle injuries are especially common in sprinters and those playing sports involving sudden acceleration and sprinting such as football and rugby. Onset is most often sudden causing the individual to immediately stop often clutching the back of the thigh.

Quadriceps injuries generally occur with sports involving kicking a ball such as football or rugby. The mechanism of injury is one of over-stretching or over-contraction of the muscle, but direct trauma (contusion) to the quadriceps in sports such as rugby is not uncommon.

Lumbar spine problems can cause referred pain in both the front and back of thigh due to irritation of the femoral (front of thigh) or sciatic (back of thigh) nerves. Sacroiliac joints problems can also refer pain into the buttock and back of thigh.

Underlying Causes / Treatment
Successful management of thigh injuries lies in identifying and treating the underlying causes of the injury.

Altered gluteal (buttock) muscle activation is commonly associated with hamstring injuries. The gluteal and hamstring should work together to push the thigh backward when we accelerate during running, but often the gluteal muscles fail leading to overload of the hamstrings. This is frequently associated with sway back postures where the trunk is slightly backward of the pelvis. Specific exercises to correct gluteal activation and timing in conjunction with postural correction eliminate this as an underlying cause.

While the lumbar spine can be the primary cause of thigh pain it is also an underlying cause of recurrent hamstring injuries most probably due to chronic irritation of the sciatic nerve which runs from the low back into the back of the thigh. In these cases careful assessment of the lumbar spine is needed to determine appropriate treatment which may involve manual therapy, postural correction, core stability, and other specific exercises.

Other treatment strategies include stretching exercises to restore hamstring and quadriceps flexibility, and various strengthening exercises to ensure the muscle is strong enough to handle the loads placed upon it with a return to normal activity.