Bridge with resisted hip abduction on BOSU ball, single leg extension ("Bridge" Core/hip stabilization, with band, straightening leg, feet on BOSU)

Tie a resistance band around both thighs just above your knees.
Lie on your back with your knees bent and legs hips width apart.
There should be tension in the band and your feet should be positioned on the rounded side of the Bosu ball.
Raise your hips up into a bridge, keeping the knees hips width apart.
Maintaining this space, straighten one leg out in front of you.
Bring the leg back to the ground.
Control the movement back down to the start position, maintaining constant tension on the band.