Gregg D'Andrea, 48: The Rock Star

Height/weight/body fat percentage: 5-6/160 pounds/7 percent

Longest spinning class ever taught: Eight hours, for charity

How he'll work you out: Strengthening your core, lifting weights, and definitely one of his signature spinning classes

You'll like him when: he contorts your frame into perfect posture mid-exercise, giving you a glimpse of what your body would look like if you didn't treat it like a garbage scow.

You'll dislike him when: he insists on having you do every exercise on a stability ball, serving to remind you that you're both out of shape and uncoordinated.

You'll do a double take when: he tells you how much water you should be drinking a day to look lean and fit. I started drinking more than a gallon a day on his recommendation, and my kidneys have never had more definition.

Perfect fit: Between his up-to-the-minute jeans and cut physique, D'Andrea is just right for those folks who want some style with their sweat.