Whittle your waist with this move, which uses the arms and legs as levers to up the abdominal burn and strengthen your back. Amy Dixon, personal trainer and head of group fitness at Equinox Santa Monica, uses the wood chop with leg swing in her "Give Me 10: Core Cuts" DVD. It's a nice change of pace from the traditional bicycle crunch.
What it does
This exercise sculpts the obliques and back while stretching your legs.
What to do
Lie flat on your mat with your legs bent and feet on the floor. Extend your right leg and clasp your hands, bending them back over your left shoulder. From there, crunch up, swinging your clasped hands across your body out in front of your right hip as your right leg lifts up to the ceiling. Lower your leg without resting it on the floor and bring clasped hands back to the starting position over your left shoulder. Repeat. Beginners can make this less intense by pulling in a bent knee instead of lifting and lowering a straight leg.
Do three sets of 12 repetitions on each side.