Tone and strengthen your arms, abs, back, butt, core, legs and shoulders in a short amount of time. By hitting multiple muscle groups at the same time, you score a total body workout in 30 minutes flat. Plus, since it doesn't dwell on any single muscle for very long, it lets you train harder. All you need is a pair of dumbbells, 5-10 pounds. Trust us, you'll feel sore the next day.
