Boot-Camp Workout

Fitness boot camps never go out of style for good reason: The military-inspired workouts burn serious calories. "Built on three fundamentals of training—cardio, strength, and agility—boot-camp workouts require little more than your body weight to get results," says Christopher Mohr, Ph.D., R.D., of Mohr Results Adventure Boot Camp for Women in Louisville, Kentucky. "They're more intense than any fitness class and more fun than traditional gym workouts."

Try these expert tips and our "SQUAD FIT Boot-Camp Workout" to kick your body transformation into high gear.

Stick to Basics
Put aside your stability ball: Boot camps are all about bare essentials, starting with the moves. By stringing together exercises like jumping jacks, pushups, and squats into circuits that go from one move to the next with little or no rest in between, these workouts turn your body into an uber-efficient resistance machine. "The moves target muscles throughout your entire body," Mohr says. "They're much more effective than equipment-based exercises that isolate one single muscle group at a time."

Follow the Clock
"Set a time limit for each exercise— think 20 to 60 seconds," says trainer Laurel Blackburn, owner of Boot Camp Fitness and Training in Tallahassee, Florida. It keeps you from pushing too hard and from slacking. "If I told you 'Do squats until I say stop,' you wouldn't give 100 percent. But if I said 'Do squats for 30 seconds,' you'd work harder because you'd see the end in sight."

Take it Outside
Without fancy equipment or complicated moves, you can do a boot-camp workout anywhere—a park, a playground, even a parking lot. And taking your sweat session outside has some serious perks: When researchers compared the mental benefits of an outdoor workout with an indoor one, 71 percent of the fresh-air exercisers felt less tense afterward, while 72 percent of the cooped-up crew felt even more stressed.

Buddy Up
One key to success is camaraderie. "A group makes you accountable to show up, and the support helps you push through an intense workout," Mohr says. When it comes to fitness, the power of your peeps is well documented: One review of 87 studies on nearly 50,000 subjects found a clear link between social support and exercise. Enlist a small group of friends who have similar fitness goals and pick a time and place. If you're a no-show, next time they'll make you drop and do 20.