The Killer Body Workout For Summer

Too many studies to ignore have shown that high-intensity interval training (HIIT) can boost muscular and cardiovascular fitness as effectively as steady-state cardio--in half the time. This HIIT routine was created for Oprah.com by Jessica Matthews, an exercise physiologist for the American Council on Exercise (ACE), and includes strengthening exercises that target the parts of you soon to be exposed in a swimsuit (i.e., almost all of your parts). Matthews recommends doing each move for 30 seconds, followed by 30 seconds of walking in circles to bring your heart rate down. After completing all seven exercises, rest for one minute. Repeat the circuit two to three times. Warm UpMatthews is a big fan of a dynamic warm-up to get the muscles psyched to work (remember, this is going to get intense). She suggests doing 5 minutes of arm circles, Frankenstein walks, half squats and any other moves that cause you to bend and stretch your arms and legs. *That includes a warm-up!

"This move really challenges the core without hurting the spine, and also works the hips, glutes and upper body, giving you a lot of bang for your buck," says Matthews.1. Start in a high plank position, with palms on the ground underneath the shoulders (not slightly out to the side, as in a push-up position), arms straight, toes tucked under, quads and abs engaged and head aligned with your spine. Bend your left knee and bring your left foot up toward the outside of your left hand. (Don't worry if you can only get it halfway up there.) 2. Step the left foot back to meet the right foot. You should be in plank position again. 3. Repeat the move with your right foot.

After mastering this cardio-and-strength combo, you'll feel as body-confident in your shorts as professional sprinters are in their racing briefs. 1. Begin in a half-kneeling position with your right foot forward and left leg back, and bend both elbows. 2. Keeping your abs engaged, draw your left arm forward and your right arm back, like you're about to take off in a race. 3. Exhale as you drive your left knee and right arm forward and up.4. Hold this position briefly before returning to your starting position.5. Repeat on the same side for 15 seconds, then switch to the other arm and leg. 6. Not hard enough for you? Matthews suggests kicking up the intensity by rising up onto the toes of the standing leg.

Like classic push-ups, these work the chest, shoulders and core, but they also strengthen the triceps (and firm up jiggly under-arms) more effectively than almost any other exercise, found an ACE-funded research study. 1. Begin in a kneeling position. Place your thumbs and forefingers together in a triangle shape directly underneath your chest. 2. Now straighten your legs (or keep your legs bent with knees on the ground) so that you're in a push-up position. Engage your abdominals and slowly bend your elbows, allowing them to flare slightly outward. Lower your chest toward the floor. 3. To come up, push through the outside surface and heel of your palms until your arms are fully extended.

This fitness-inspired twist on a yoga boat pose, or navasana, works the entire core as well as the hard-to-target hip flexors, says Matthews, who also teaches yoga. 1. Begin in a seated position with knees bent and feet flat on the floor. Cross your arms in front of your chest.2. Slowly pick both feet up, keeping knees bent at 90 degrees. Recline the torso back slightly as you keep the core engaged and the spine long. This is the high-boat pose.3. As you inhale, lower back with control. Extend the legs out in front of you and recline your torso closer to the floor. This is the low-boat pose. 4. As you exhale, rise back up with control into high-boat pose.

Matthews promises that these Apolo Ohnostyle side lunges will get your heart rate up and work the entire lower body. 1. Stand with feet hip-width apart. 2. Leap out to the right with the right foot, crossing the left leg back behind the right, and touch the toes to the ground. 3. Repeat to the opposite side, leaping out with the left foot as you cross the right leg behind the left. 4. Alternate sides in a rhythmic swish that works the glutes, hamstrings, quads and calves (i.e., the areas that will inevitably be captured on film by someone trying to get a shot of their kids frolicking in the surf).

You may have heard of burpees, often considered to be the perfect (and perfectly dreadful) total-body exercise . Matthews says tuck jumps are the first half of a burpee -- and they can feel just as intense.1. Start in a high plank position on a mat (if you have one). Using the strength of your entire body, jump both feet between your hands, coming to a low squatting position at the top of the mat. 2. When youre ready, jump both feet towards the back of the mat. Return to the high plank position.3. Too challenging? No worries. Instead of jumping, step one foot up at a time to meet the hands. Then step one foot back at a time to the back edge of the mat. "This low-impact version is more friendly to the joints but still provides a total-body challenge," says Matthews.

Take the core-strengthening plank up a notch with this move that also involves the obliques and upper back.1. Lie on your stomach and fold both forearms in front of your chest so that they are parallel with the top edge of the mat. 2. Lift your body into a plank position (like you did for toe taps), but keep your forearms on the mat.3. Shift your weight onto your left forearm as you open your body toward the right side of the mat. Your right foot should come slightly in front of the left as you drive the right elbow up and back. 4. Slowly come back to center with both forearms on the ground.5. Repeat the movement on the opposite side.