What You'll Need
A set of dumbbells (a pair of 3- or 5-pound weights if you're a beginner; if you're more experienced, try 5- or 8-pound weights); a mat or carpet; and a jump rope.

Your Strategy
When you're performing the strength moves, choose a weight light enough for you to complete 15 repetitions, but heavy enough to make the last three reps challenging.

The Workout
After the warm-up, the routine features a four-part circuit. Do the moves in order, with no more than 15 seconds rest in between to keep your heart rate elevated. Perform the circuit three times, then move on to the cooldown and stretches. Do this workout three to four days a week, waiting a day in between to let your muscles recover.

1. Cardio: Jumping Jacks | Sky Reaches

Do one set of 20 jumping jacks to raise your heart rate.

Follow with 20 sky reaches: Stand with feet hip-width apart, knees slightly bent, abs in, and back straight. Reach both hands to the ceiling, then bend knees and lower body in one swift motion so hands touch the floor. Keep your eyes focused ahead to prevent dizziness. If you find it difficult to reach the floor, touch your knees instead.

Do another set of 20 jumping jacks.

2. Strength: Reverse Lunge | Bicep Curls (works the buttocks, hamstrings, calves, and biceps)

Stand with feet shoulder-width apart, arms at your sides. Hold a dumbbell in each hand, palms forward. Take a large step back with your right foot, and lower hips so your front and back thighs form 90-degree angles with your knees. As you step back, bring the dumbbells to your shoulders (keep your elbows at your sides). Your weight should stay in the heel of your front foot; don’t let your knees go past the toes. Push off with your back leg while lowering the weights, returning to start. Do 15 repetitions with your right leg, then the left.

3. Cardio: Jump Rope | Side Jumps

Stand with feet together, and jump rope for 30 seconds. Jumping high or fast isn't important—just try to find a rhythm.

Next, set the rope on the floor in a vertical line, and jump over it, from side to side, for 30 seconds. Keep your feet together.

Jump rope again for 30 seconds.

4. Strength: Bent-Over Dumbbell Rows | Straight-Arm Triceps Extensions (works back, shoulders, and triceps)

Stand with feet shoulder-width apart and knees bent, holding a heavy dumbbell in each hand, palms facing your legs. Lean forward as far as it's comfortable (you're aiming for your torso to be parallel to the floor) while keeping your back flat. Check your form in a mirror if you can; try pulling in your stomach to help straighten your back. Bend your elbows, and lift your upper arms, keeping them close to your body, until the weights almost reach the level of your torso. Slowly lower and repeat. Do 15 repetitions.

Choose a lighter weight, and start in the same position as the dumbbell rows, with your back flat and arms hanging. Keeping your arms straight, lift them backward until they're parallel with your body. Lower, and repeat 15 times.

Do another set of both dumbbell rows and triceps extensions.
Repeat the entire circuit two more times.

Cooldown
March or jog in place, or do any light cardio exercise for three to five minutes.

Stretches

Glute | Hamstring Stretch: Lie on your back with legs extended. Bend your right leg into your chest, and clasp hands around your knee. Hold for 30 seconds. Next, extend your right leg to the ceiling, placing one hand behind your thigh for support. Hold for 30 seconds. Repeat with the left leg.

Hip Stretch: Sit on the edge of a chair with feet flat on the floor, and cross your right ankle over your left knee. Place your right hand on your right knee, lean forward, and gently press for 30 seconds. Switch legs, and repeat.

Shoulder Stretch: Stand with feet shoulder-width apart, and bring your right arm across your body at shoulder level. Using your left hand, gently push your upper arm toward your chest. Hold for 30 seconds, release, and switch arms.

Calf Stretch: Stand with hands flat against a wall. Flex your left foot, and place your left heel on the floor a few inches from the wall. Press the ball of your left foot into the wall, feeling the stretch in your calf. Your knee should be slightly bent. Hold for 30 seconds, then switch legs.