If you've been searching high and low for the secret to getting a flat stomach and six-pack absbut haven't had any luckyou're not alone. After years of doing a bazillion crunches during every workout I finally learned that determination only gets you so far when the approach is wrong. Even an entire hour of crunches won't match the body benefits of a 10-minute plank workout. The plank is one of the best exercises for a strong stomach because it works all the muscles in your core.