Hip thrust on stability ball - alternate leg lifts - version 3

Sit on a stability ball and walk your feet forwards until the ball is under your shoulder blades.
Lift your hips up high, driving the movement with your buttock muscles.
Holding this position, lift one leg up while bring your hands towards the ceiling.
lower your arms and leg then repeat the movement with the opposite leg.
It is important that you keep your hips up and level throughout this exercise.