Knowing the area:
There are two main muscles in the thigh: the hamstrings, located at the back of the thigh, and its opposing muscle, the quadriceps which are located on the front.

Common Problems:
The most common complaint in this area is a hamstring pull. Occasionally, the quadriceps can tear or pull as well.

Common Cause:
Pushing the body too hard especially during sports that involve a lot of running and jumping or athletics. The hamstrings can pull or rip when the body is tight and unyielding before exercise.