America's Hardest Workout Classes

Warrior Workout

Try It At: Pow! Krav Maga Martial Arts and Fitness Training Center, Chicago

The Benefit: You'll supersculpt your lower body and learn to fight like a pro.

Calories Burned: 400 to 600

Instructor Katalin Rodriguez-Ogren warms up the class with six to eight minutes of jump rope mixed with leg lifts, half squats, and skipping with knees high. Next comes a series of knee strikes, kicks, and jab combos, and then they hit the heavy bag. Afterward, students run up and down seven flights of stairs.

Signature Move: Roundhouse Drill

Stand with feet hip-distance apart and fists protecting your face. First, perform roundhouse kicks continuously for 30 seconds with your right leg, kicking in an arc from right to left, keeping knee bent between each kick. Next, hold your right knee to hip height and pulse leg up and down for 30 seconds. Then kick with an extended leg for 30 seconds. Finish by holding the extended right leg out to the side and pulsing for 30 seconds. Switch legs and repeat.

At Home: Try G.I. Jabb Warrior Workout DVD, $29.95 at exercisedvds.com.