Standard approach: From the sitting groin stretch position straighten your left leg (but keep a slight flex) and keep your right leg bent, with the bottom of your right foot against the inside of your left thigh. Bend forwards from the hips to feel a slight stretch.

Improved: Don't try to touch your forehead to your leg - this will cause you to round your shoulders. Keep looking straight ahead, keep your left foot pointed up; turning it to the outside will misalign your leg and hip and lessens the effectiveness of the stretch by reducing resistance.