Sets: 3 / Reps: 8

Target: abs, core

Why it works: Your abs work across a plane of motion that includes the point where your torso is arched back slightly. Doing weighted crunches on a Swiss ball rather than the floor allows you to exhaust the abs across their whole range for increased muscle growth potential.

• Sit on a Swiss ball holding a weight plate or medicine ball with both hands across your chest.
• Lower yourself all the way back.
• Crunch up by contracting your abs as if you were trying to curl your body around a ball.