Head-to-Toe Strength-Training Routine

Here's a killer core exercise using an exercise ball.

• Kneel down on the floor, and place your forearms on a gym ball.
• Straighten your legs behind you.
• Keeping your core strong and your body still, use your arms to roll the ball in small counter-clockwise circles. Do five circles in this direction and five clockwise.
• This counts as one set. Complete three sets without any breaks if you can.