Virabhadrasana
Warrior I, Virabhadrasana I
The detail to copy here is the back foot: flat on the mat and turned out, while the front knee bends over the ankle and both arms reach straight up. The pose is named for Virabhadra, a warrior of Hindu legend. It strengthens the legs and stretches the hip flexors of the back leg.
If the back heel keeps lifting, shorten your stance or widen your feet a little, as if standing on two train tracks, so the hips can face forward.
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