My hip flexors are one area of my body that could always use some extra attention. Here's a lunge variation, similar to Warrior 1,
but with your back knee resting on the floor, you can really increase
the stretch for the muscles on the front part of your back thigh.
Arching your spine backward also offers a great stretch for the abs and
shoulders; not to mention it strengthens your core and increases
flexibility in your spine.