In this Yoga Tune Up® Half Happy Baby Minivini pose, the sartorius is highlighted as both the agonist (the worker) and the antagonist (the stretcher). The happy baby leg is dynamically activating the sartorius when the hip is externally rotated, abducted and both the hip and knee are flexed. The leg that is extended on the floor stretches the sartorius passively. Try this Half Happy Baby Minivini exercise for the sartorius:
This pose can be done on its own, or can be a warm up for other Yoga Tune Up® poses where the sartorius is highlighted. In Splat Frog with Internal Rotation, simply being in frog highlights the sartorius, and internally rotating the flexed knee further activates this muscle. Another pose, Setu Bandha (Bridge) creates a yummy release for the sartorius by posteriorly tilting the pelvis and contracting the buttocks.
This hip extension is such a lovely treat for the heavy flexing sartorius! For a more detailed sequence, try the Quick Fix for Hips Video.