Holding a medicine ball in your hands, elbows by your sides, take one large step forward into a lunge position.
Watch that your knee is at a 90 degree angle and the weight of your body is toward your front knee.
Hold the lunge position, contract your abs and rotate your torso to the same side as your front leg.
Your arms and medicine ball should turn with your torso until they are in line with your side.
Rotate back to the centre as you stand up and bring your arms back in front of you.