Bursae are positioned between bones throughout your body. They act as cushions between soft tissue and bone to reduce friction, and are small, jelly-like sacs that contain a small amount of fluid. Bursitis is inflammation of the bursa.
Many experience a sharp sudden pain near the back of the thigh during a fast stretching movement or sprint. The semitendinosus, semimembranosus and biceps femoris are the 3 separate muscles that make up the hamstring group. The strain occurs when there is a pull or overstretch and many can often hear a “pop” when the muscle becomes damaged.
Quadriceps muscles are important for bending the hip and straightening the knee. A quadriceps strain is a tear in the muscle or tendon on the front of the thigh.