How to do it…

Place the ball between you and the wall so that the curve of the ball supports the curve in your lower back.  Your feet should be shoulder width apart or slightly wider with your feet turned out, and slightly in front of your hips.

Roll down the ball into the squat or ‘sit’ position, ensuring you push back into the ball and roll around it so that no gap develops between you and the ball. As you do so draw your tummy in and lift your chest.  Ensure that your knees track in line with your toes (not rolling inwards or outwards). When learning the exercise a brief pause at the bottom allows you to check this position.  Then push through your legs and buttocks to come up to the standing position.  Repeat 10-30 times before taking a brief rest. You can perform several sets of the exercise for maximal gains in strength.