Oprah.com: 10 New Exercises for Women.

The benefit: It’s one of the simplest, yet most effective ways to tighten your tummy. In fact, you’ll barely have to move a muscle.
How to do it: Assume a pushup position with your arms completely straight, but place your hands on a Swiss ball instead of the floor. Your body should form a straight line from your head to your ankles. Tighten your core and hold it that way for the duration of the exercise. Lift one foot off the floor and slowly raise your knee as close to your chest as you can without changing your lower-back posture. Then repeat with your other leg. Alternate back and forth for 30 seconds. If that’s too hard, place your hands on the floor or a bench.

The benefit: It targets the muscles of your rear end, which can help make your belly flatter. The reason: When your glutes are weak—as they are in most women—the top of your pelvis tilts forward. This not only places stress on your lower back, but it causes your tummy to stick out—even if you don’t have an ounce of fat. Your fix: the hip raise.
How to do it: Lie on your back on the floor with your knees bent and your feet flat on the floor [A]. Now brace your core, squeeze your glutes, and raise your hips so your body forms a straight line from your shoulders to your knees [B]. Pause for 3 to 5 seconds—squeezing your glutes tightly the entire time—then lower back to the start.

The benefit: Holding a weight on just one side of your body increases the demand placed on your core to keep your body stable. The result: Your hips and abs have to work harder, and you’ll also improve your balance. And better yet, you’ll burn tons of calories.
How to do it: Hold a dumbbell in your right hand next to your shoulder, with your arm bent [A]. Step forward with your right leg and lower your body until your right knee is bent at least 90 degrees and your left knee nearly touches the floor [B]. Push yourself back to the starting position. That’s one rep. Do all your reps, then repeat with your left leg, while holding the weight in your left hand.

The benefit: Besides targeting your hamstrings, this exercise works your glutes and core. It also helps eliminate muscle imbalances between your legs, reducing your risk of injury. And as a bonus, it can improve the flexibility of your hamstrings, because it stretches these muscles every time you lower the weight.
How to do it: Grab a pair of dumbbells with an overhand grip and hold them at arm’s length in front of your thighs. Stand with your feet shoulder-width apart and knees slightly bent. Now raise one leg off the floor [A]. Without changing the bend in your knee, keep your back naturally arched, bend at your hips, and lower your torso until it’s almost parallel to the floor [B]. Pause, then squeeze your glutes, thrust your hips forward, and raise your torso back to the starting position.

The benefit: This exercise works your glutes and abs as hard as it works your chest and triceps. So you’ll tighten your hips and core as you tone your upper body.
How to do it: Grab a dumbbell in your left hand and lie on your back on a flat bench. Hold the dumbbell over your chest with your arm straight. Your palm should be facing out, but turned slightly inward. Place your right hand on your abs [B]. Lower the dumbbell to the side of your chest. Pause, then press the weight back to the start. Do all your repetitions, then repeat on your right side.

The benefit: When you raise the dumbbells to start this exercise, you target the front of your shoulders, as well as your rotator cuff. Then comes the shrug. This part of the move helps better balance the muscles that rotate your shoulder blades. The end result: great-looking shoulders and better posture.
How to do it: Stand holding a pair of dumbbells with your feet shoulder-width apart. Let the dumbbells hang at arm’s length next to your sides, your palms facing each other [A]. Without changing the bend in your elbows, raise your arms at an angle to your body (so that they form a ”Y”), until they’re parallel to the floor [B]. At the top of the movement, shrug your shoulders upward [C]. Pause, then reverse the movement to return to the start, and repeat.

The benefit: Lying on a Swiss ball forces your core to work harder to keep you stable. So you work your abs as you shape the backs of your arms.
How to do it: Grab a pair of dumbbells and lie on your back on a Swiss ball that your middle and upper back are on the ball. Raise your hips so your body forms a straight line from your knees to your shoulders. Hold the dumbbells over your forehead, with your arms straight and your palms facing each other [A]. Without moving your upper arms, bend your elbows and lower the dumbbells until your forearms are beyond parallel to the floor [B]. Pause, then lift the weights back to the start.

The benefit: Placing one foot in front of you on a bench forces your hip and core muscles to work harder in order to keep your body stable. That way, you engage more muscles and burn more calories than you would if you did the exercise in a regular standing position.
How to do it: Grab a pair of dumbbells and place one foot in front of you on a bench or step that’s just higher than knee level. Let the dumbbells hang at arm’s length next to your sides, your palms facing forward [A]. Without moving your upper arms, bend your elbows and curl the dumbbells toward your shoulders [B]. Pause, then slowly lower the weights back to the start.

The benefit: This exercise targets your upper back. By working these key muscles, you’ll improve your posture, shape the back of your shoulders, and look great in a backless dress.
How to do it: Lie facedown on top of a Swiss ball so your back is flat and your chest is off the ball. Let your arms hang straight down from your shoulders, your palms facing behind you [A]. Keeping your elbows flared out, lift your upper arms as high as you can by bending your elbows and squeezing your shoulder blades together. Your upper arms should be perpendicular to your torso [B]. Without changing your elbow position, rotate your forearms up and back as far as you can [C]. Pause, then reverse the movement. If you can do more than 12 repetitions, use dumbbells.

The benefit: This exercise works your core while keeping your lower back in its naturally arched position. So it minimizes stress on your spine while increasing the endurance of the muscles, which helps prevent lower-back pain.
How to do it: Lie on your back on the floor with your left leg straight and flat on the floor. Your right knee should be bent and your right foot flat. Place your hands palms-down on the floor underneath the natural arch in your lower back [A]. Slowly raise your head and shoulders off the floor, without bending your lower back or spine, and hold this position for 7 to 8 seconds, breathing deeply [B]. That’s one rep. Do 4 to 5 reps, then switch legs and repeat.

Read more at oprah.com or learn more about the the Women’s Health Big Book of Exercises and where to buy the book.