Get down on all fours,
with your knees under your hips and wrists
under your shoulders. Pull in your abs, draw
your shoulder blades back and down, and
lengthen your spine. Keeping your right knee
bent, lift that leg behind you, keeping your
thigh and knee in line with your shoulder. Flex
your foot and squeeze your right buttock.
Press your foot up to the ceiling, giving your
buttock an extra tight squeeze at the top of
the movement [shown]. Do 15-20 reps on one
side, then switch legs.