To properly stretch the quadriceps, this stretch is performed in two parts.

Part I

To stretch the portion of the quadriceps nearest your hip:

1. Lie on your left side with your left hip flexed and your left thigh pulled as close to your chest as possible. This prevents you from arching your low back.
2. Straighten right hip so the right upper thigh is inline with the rest of the body.
3. Contract the right hamstring muscles to gently stretch the quadriceps.
4. Place your right hand on the top of your right foot and gently apply 1 lb. of additional force, approximating your right ankle to your right buttock.
5. Hold this position for 1.5 - 2 seconds then return to the starting position.

Repeat the above steps for a total of 10 - 15 repetitions on both the right and left legs.

Make sure you do not allow your knee to flare up and away from your body during the stretch.

Part II

To stretch the portion of the quadriceps farthest from your hip:

1. Lie on your left side with your left hip flexed and your left thigh pulled as close to your chest as possible. This prevents you from arching your low back.
2. Place your right hand on the top of your right foot.
3. Contract your right buttock (gluteus maximus) and hamstring muscles to move the right thigh as far backward as possible while approximating your right ankle to your right buttock.
4. Use your right hand to gently apply an additional 1 lb. of force in the direction of the stretch.
5. Hold this position for 1.5 - 2 seconds then return to the starting position.

Repeat the above steps for a total of 1 - 2 sets of 10 repetitions on the right and 10 repetitions on the left.  Alternate legs after each set.

Make sure you do not allow your knee to flare up and away from your body during the stretch.