10 Tone-Up Tweaks to Get a Better Burn

Back: Kick It Up with a Kettlebell

Kettlebells are so effective because they rely on acceleration as well as deceleration to help tone muscle. "The off-centered weight of a kettlebell will force you to use more stabilizer muscles and work the targeted muscles through a longer range of motion," says celebrity trainer Michelle Lovitt, whose clients include Courteney Cox and Julianne Moore. Since you need your arms to hoist the kettlebell in the air, you're targeting two zones with one area.

Bring out your best back with this kettlebell circuit