Why you should roll your Rectus Femoris
If you suffer from patellar tendonitis, foam rolling your rectus femoris can take some load off your patellar tendon. Rolling your rectus femoris also helps with improving your posture, as the RF is a hip flexor and can pull you into anterior pelvic tilt, which places more stress on your back.
How to do it
Lie down on your stomach and place the roller on the front of your thighs. Roll your thigh muscles in short strokes, starting near your hip and remember to bend your knees to hit all parts of the muscle.
You can also roll your rectus femoris with a stick.