BodyPump—Resistance Training to Music. This is by far the fastest way to get your muscles lean and in shape with that "cut" look/without getting bulky. And the music makes you move!
And, here's probably the most important piece of information: you choose the amount of weight you want to use. Your instructor will only give you options and suggestions for the amount of weight you use. The decision is totally up to you. And the results are fast!