For a more intense stretch in the backs of your thighs and calves, try elevating your foot on a roller. But it's important to put only your lower ankle and heel on top of the roller; this avoids any pressure on your Achilles tendon.
1. Sit upright on the floor with your left leg straight in front of you and your left heel on top of the roller. Bend your right knee and position your right foot against the inside of your left knee (if your left knee tends to hyperextend, place your right foot directly under your left knee for support). Inhale, sit up tall and reach your arms overhead.