Crunches aren’t the only way to tighten up that tummy. This move will whittle your waistline, strengthen your back—and build your balance, to boot.
A. Kneel on all fours, making sure your knees are directly under your hips and hands under your shoulders.
B. Keeping your abdominals tight and your back long, extend your left arm and right leg. Hold for three to five breaths and then return to tabletop position. Repeat on the opposite side for one set. Do three to five sets, slowly increasing the length of time you hold the pose.