Cardio-Sculpting Workout: 21 Days to Loving Your Shape

The 21-Day Plan

Sure, we're suckers for a workout that promises flat abs and a tight butt as much as the next girl. But there's a more important reason to exercise: It makes you feel great. "Good mental health is just as important as good physical health, and exercise is crucial to getting both," says trainer Jeanette Jenkins, author of The Hollywood Trainer Weight-Loss Plan: 21 Days to Make Healthy Living a Lifetime Habit. Her plan celebrates all of the fab stuff that comes with exercise: more energy, better health, and the motivation to keep coming back for more. So while this routine will definitely help you see an improvement in the right-around-the-corner skimpy-outfits season, it'll also help you love the shape you're in, inside and out.

This 21-day plan is designed for all fitness levels, so follow the exercise and cardio variations that are right for you. Lacing up after a long layoff? Use the three weeks to make exercise a lifelong habit. If you're already in the swing of things, there are plenty of challenges here to boost your results.

The program consists of four primary workouts: three strength circuits and a cardio routine. Each circuit focuses on a different set of muscle groups; the cardio plan is designed to blast calories and improve your aerobic fitness. For best results, do the workouts in the order given below.

• A set of light (3- to 5-pound) and medium (8- to 10-pound) dumbbells

Day 1: Cardio, stretch
Day 2: Circuits A & C
Day 3: Cardio, stretch
Day 4: Circuits B & C
Day 5: Circuit A, stretch
Day 6: Circuits B & C
Day 7: Rest and rejuvenate (Repeat for weeks 2 and 3)

1. Push-Up/Plank Combo

Chest, Triceps, and Rear
Do this circuit 4 times through (advanced, do it 6 times)

Targets shoulders, triceps, chest, abs

• Begin in a modified push-up position, hands on ground slightly wider than shoulders and knees down. Keep a straight line from the top of your head through your legs, abs tight. Bend elbows 90 degrees, then push back up to start.
• Do 20 to 25 reps. (Not shown.)
• After your last rep, lift your knees off the ground so you're in a full push-up position with legs extended. Keeping abs tight and back straight, hold for 30 seconds.

Challenge yourself: Do full push-ups; hold plank 60 seconds.

2. Chest Flye

Targets shoulders, chest

• Lie faceup on the ground with knees bent, holding heavier dumbbells with arms extended, palms facing each other.
• Slowly open arms out to sides, keeping elbows slightly bent; stop when weights are about an inch above the ground.
• Push weights back to starting position. Do 15 reps.
• Immediately pick up the lighter set of weights and repeat; do 10 more reps.

Challenge yourself: Do 25 reps with the 8- to 10-pound weights.

3. Reverse Lunge

Targets glutes, hamstrings, quads

• Stand with feet hip-width apart, holding lighter set of dumbbells with arms at sides, palms in.
• Lunge right foot behind you, lowering right knee toward ground; bend left knee 90 degrees, keeping it aligned over ankle.
• Return to start, driving body weight through your left heel; bring right knee to hip level (not shown).
• Repeat. Do 15 reps; switch legs.

Challenge yourself: Hold heavier dumbbells and/or do 25 reps per side.

4. Squat/Chair Pose

Targets glutes, hamstrings, quads

• Stand with feet shoulder-width apart, holding lighter dumbbells on shoulders.
• Squat down, pushing butt behind you; keep body weight over heels.
• Push through heels to return to start, squeezing glutes. Do 20 to 25 reps.
• After last rep, drop weights and bring feet together. Resume squat position, keeping knees behind toes and extending arms in front at chest level; hold for 30 seconds.

Challenge yourself: Use heavier dumbbells and hold chair pose for 60 seconds.

1. Plie Squat

Back, Biceps, and Thighs
Do this circuit 4 times through (advanced, do it 6 times)

Targets glutes, quads, inner thighs

• Stand with feet slightly wider than shoulder-width apart with toes turned out, holding lighter dumbbells vertically in front of thighs.
• Keeping abs tight and torso tall, bend knees 90 degrees; keep knees aligned between second and third toes and weight in heels.
• Press back to start; squeeze your glutes. Do 15 reps.

Challenge yourself: Use heavier weights and/or do 25 reps.

2. Biceps Curl

Targets biceps

• Stand tall with feet together, knees slightly bent. Hold a heavy dumbbell in each hand with palms facing up.
• Slowly curl the weights toward your shoulders, contracting your biceps.
• Slowly lower the weights to start and repeat. Do 15 reps.
• Immediately pick up the lighter set of weights and repeat; do 10 more reps.

Challenge yourself: Do 25 reps with the heavier weights.

3. Inner/Outer Leg Lift

Targets glutes, outer and inner thighs

• Stand with feet hip-width apart, arms extended at shoulder height, palms down.
• Lift left leg to side, squeezing outer thigh and glutes. Do 15 reps.
• Without touching floor, bring left leg in front of body, rotating inner thigh to face forward. Press left heel forward; do 15 reps (not shown).
• Switch sides and repeat from beginning.

Challenge yourself: Do 25 reps per leg.

4. Back Flye

Targets upper back, shoulders

• Stand with feet hip-width apart, right leg about 3 feet behind left. Hold heavier dumbbells with palms facing each other.
• Bend forward from waist, extending arms toward ground diagonally just in front of left knee.
• Slowly open arms straight out to sides to shoulder level, contracting the muscles of your upper back. Slowly lower weights and repeat.
• Return to center and repeat; do 15 reps.
• Immediately pick up the lighter set of weights and repeat; do 10 more reps.

Challenge yourself: Do 25 reps with the heavier weights.

1. Roll-Up

Core
Do this circuit 4 times through (advanced, do it 6 times)

Targets deep (transverse) and "six-pack" (rectus) abdominals

• Lie faceup on ground with knees bent, arms extended next to ears, palms facing up.
• Reach your arms straight as you contract your abs and lift your head, neck, and shoulders off the ground. Keep your spine rounded, moving as smoothly as possible.
• When you're all the way up, pull your abs in tight and roll back down one vertebra at a time. Do 8 reps.

Challenge yourself: Keep legs straight.

2. Side Reach

Targets obliques, deep (transverse) abdominals

• Lie on the ground on your right side with legs stacked, right arm on ground and left arm on top of left leg.
• Keeping abs pulled in, reach left hand down as if going to touch ankle (you'll move only slightly off the floor), feeling the contraction along your side.
• Slowly lower back down, using your obliques and abs to provide resistance. Do 8 reps; switch sides and repeat.

Challenge yourself: Lift your legs slightly as you reach toward ankles.

3. Boat Pose

Targets deep (transverse) and "six-pack" (rectus) abdominals

• Sit on the ground with knees bent, feet hip-width apart. Place hands under thighs, inhaling deeply.
• Exhale, lifting feet off the ground (keep knees bent) and pulling abs in tight.
• Lean back slightly, balancing on your tailbone, and open arms wide out to sides. Hold for 8 breaths, return to start, and repeat. Do 3 reps.

Challenge yourself: Straighten legs about 45 degrees to ground.

Calorie-Blasting Cardio Workout

These treadmill workouts are designed to blast 300 to 500+ calories in about 40 to 50 minutes. Choose from one of three levels (beginner, intermediate, advanced) and pick either a high-impact run or a low-impact speed walk on an incline. Don't have access to a treadmill? Do the same program outside on flat or hilly terrain. Follow your cardio workout with 5 to 10 minutes of stretching for your shoulders, chest, hips, glutes and legs.

0:00-5:00: Warm up, 3.5 mph, 0%

5:00-7:00: Speed-walk, 4.0 mph, 0%

7:00-9:00: Run, jog (5.2-6.0 mph, 0%) or speed-walk (3.8 mph, 6%)

9:00-33:00: Repeat minutes 5:00-9:00 six more times, alternating 2 minutes of walking with 2 minutes of running or walking on an incline

33:00-38:00: Cool down, 3.5 mph, 0%

0-5:00: Warm up, 3.5 mph, 0%

5:00-7:00: Speed-walk, 4.0 mph, 0%

7:00-22:00: Run, jog (5.2-6.0 mph, 0%) or speed-walk (3.8 mph, 6%)

9:00-39:00: Repeat minutes 5:00-22:00, alternating 2 minutes of walking with 15 minutes of running or walking on an incline

39:00-45:00: Cool down, 3.5 mph, 0%

0-5:00: Warm up, 3.5 mph, 0%

5:00-10:00: Run, jog (5.2-6-0 mph, 0%) or speed-walk (3.8 mph, 6%)

10:00-12:00: Sprint (6.0-7.0 mph, 0%) or speed-walk (3.8 mph, 10%)

12:00-47:00: Repeat minutes 5:00-12:00 5 more times, alternating 5 minutes of running or walking on an incline

47:00-52:00: Cool down, 3.5 mph, 0%

Adapted from The Hollywood Trainer Weight-Loss Plan by Jeanette Jenkins with permission of G.P. Putnam's Sons, a member of the Penguin Group USA. Copyright 2007 by Jeanette Jenkins.

Originally published in FITNESS magazine, May 2007.

All-New! Motivation Playlist

Great music can actually help you burn more calories and keep you inspired to work harder, says Jenkins. Here are her latest favorite mixes.