Doing strenuous physical activities like running, playing sports like basketball and football and even just being exposed to a very cold weather can cause an pain in the quadriceps muscles or quads. Here is a simple exercise that you can do to relax the muscles in this area.
For the quads
1. In a prone lying position and put the foam roller on one side of the crease your hip. Use your other leg to support your body. Then, pull yourself all the way down from the front of your leg to the top of your knee. And then back up to the crease of your hip.
2. Be careful not to go high up to the pelvis bone and just roll back up to the crease of your hip. You can also tilt the foot of your leg which is on the foam roller to hit the quads from a different angle.
Check out this video by Missoula Chiropractor on how to properly perform this exercise on your Quadricep muscles.