Target: hamstrings

Why it works: This move specifically isolates your hamstrings to maximise muscle exhaustion at the end of the set and improve strength gains. Because the Swiss ball is an unstable surface, your core will also have to work hard to control the movement.

• Lie on your back as shown with a Swiss ball by your feet.
• Place your heels on the ball and raise your hips so that your body forms a straight line from shoulders to ankles.
• Brace your core and roll the ball towards you.
• Squeeze your hams at the top and lower under control.