Stand up straight with your feet shoulder-width apart and arms straight above your head holding a medicine ball.
Transfer your weight to stand on one leg.
Maintaining your balance, squat down on one leg, pushing your hips back behind you.
Your other leg should hover in front of you with a straight knee.
Lift your arms forwards to help you counterbalance.
Tighten your abdominal, buttock and thigh muscles to return to standing.
Pause briefly, and repeat.