Right here, right now, we're telling you that "I don't have enough time" is no longer an acceptable reason to bail on a workout. Whether your goal is to finally hone a six-pack or to sprint five flights of stairs without losing your lunch, 20 minutes and a pair of dumbbells is all you need. To guide your way, we recruited three of the nation's top-tier trainers to design speedy routines tailored to different goals. Choose the plan that's right for you, then make time. No excuses.