These double-duty moves turn your local pool into a giant exercise machine. Not only do they simultaneously tone and strengthen your major muscle groups, they also work the upper and lower body in tandem for maximum cardio fat frying. This workout was created by Mary E. Sanders, an exercise scientist at the University of Nevada, Reno. It burns about 100 calories in only 10 minutes. Perform each exercise for 3 minutes (resting your upper body if needed), then jog for 30 seconds between exercises. Repeat to burn even more calories. Perform this workout 2 or 3 times a week. Look for water exercising accessories in sporting goods stores and pool stores. (Short on time? In just 10 minutes a day, you can transform your body with Prevention’s Fit In 10 DVD. Seriously, just 10 minutes a day. Check it out.) When exercising in the water, don’t forget these pool rules: 

Exercise in navel- to chest-deep water.Wear water shoes.Add equipment if the work’s too easy.Maintain form while increasing your speed to intensify resistance.Begin by practicing the upper- and lower-body moves separately. 

Jump & Dig Lower-body move  Assume a wide stance, then jump like a frog, bringing your knees to the surface and back down, landing on the pool floor. Your abs will love this one!Upper-body move At surface level, place your hands together so they form a scoop. Reach down, then scoop back up without breaking the surface, moving first left, then right. A killer move for your obliques, the muscles that wrap around your torso.Make it harder with water gloves; for maximum resistance, use water paddles.  Stomp & Push Lower-body move Striking a wide stance, pump your legs, alternately lifting each knee in front of you as if you were stomping grapes. Touch the pool bottom with every step. This is a great exercise for your thighs and butt.Upper-body move Hold your arms out wide and in front of you, bending them slightly. Alternately push each arm down hard to your hips, then back up again. Works your upper back and the back of your arms on the way down, your shoulders and the front of your arms on the way up.Make it harder with water gloves. MORE: Your 5-Minute Routine For Killer, Ageless Arms Scissor Press Lower-body move Place one leg behind the other in a lunge position. Flex your knees, jump, and switch legs (like you’re cross-country skiing). An awesome challenge to your legs and butt!Upper-body move Extend your arms out to the sides at the water’s surface. Keep your shoulders down and back and your elbows slightly bent. Press your arms down to your sides, then back up to the surface. Works your back and shoulders.Make it harder with water gloves, water paddles, or aquatic hand buoys.