Starting Position: Lie on your right side on a mat/floor with your legs extended straight away from your body. Bend your left knee and pull your left heel up towards your left glute muscle (buttock), use your left hand to grab a hold of the top of your left foo. Your right (lower) arm should be bent and positioned under your head for support. Your hips and shoulder should be aligned vertically to the floor. Your head should be aligned with your spine.
Stiffen your core and abdominal muscles ("bracing") to position your spine in neutral position and maintain stability through your pelvis, maintain this abdominal contraction throughout the stretch. Exhale and use your left hand to gently pull your left heel and lower leg towards your tailbone while simultaneously keeping the left thigh and knee resting on the inside of the right thigh and pointing straight out from the left hip joint. Hold this position for 30-45 seconds, then straighten the leg and contract (squeeze) the quadriceps (thigh) muscles and repeat for 2-5 repetitions; alternate sides and repeat with the right leg.
Exercise Variation: To increase the intensity of the stretch point your left knee behind your body while continuing to hold on to your left foot. Another option is to hold the stretch for 10-15 seconds, push your left foot into your hand (like trying to straighten your leg), hold for 5-7 seconds, then relax and pull your heel closer to your tailbone, repeat for 3-5 repetitions and alternate sides.
Be sure to keep the spine in a straight line and maintain the abdominal bracing to keep the pelvis stable.