There are very large muscle groups that make up the thigh. Four muscles, known as the quadriceps, work together on the front of the thigh to extend the knee. Three muscles, known as the hamstring, work together on the back of the thigh to bend the knee. Without proper warm-up, or if overused, any number of these muscles in the thigh can become strained or torn. BioSkin Compression Sleeves and Shorts provide pain-relieving compression to the area, promoting blood flow to speed recovery and enhance performance.