4-Week fitness challenge: Week 2

You’ve made it to week two of the four-week fitness challenge. Now that you’ve built your baseline with the cardio and strength routine, it’s time to get serious.

Related story The 10 Best Functional Exercises for a Full-Body Workout

This week is all about building muscle. Strength training is an incredibly important part of a fitness routine because lean muscle is compact, taking up less space in your body than fat. This means a leaner, 140-pound person will look thinner than the same 140-pound person who carries more fat.

Not to mention, muscle mass is a natural fuel burner. As you build muscle mass, you’ll burn more calories at rest than you would otherwise. As a result, your body will become a lean, toned and strong calorie-burning machine.

Related story The 10 Best Functional Exercises for a Full-Body Workout

How it works

This week, you’ll be performing three workouts. In addition to performing week one’s 30-minute cardio and strength building circuit twice, you’ll add the following strength-building routine once.

• You’ll need: Something to use as weights (dumbbells, water bottles or canned goods all work), something to use as a low platform (thick books work great).
• The workout: Perform the sets and reps for each exercise as detailed below.

1. Narrow-to-wide squat: 3 sets, 15 repetitions per set

1. With your feet together and knees slightly bent, your weight centered on your heels, tip your hips back and begin to squat down as you bend your knees.
2. Go down as low as you can while making sure your knees track with your toes without extending over your toes.
3. Push to standing, then immediately step your legs out to each side, your toes angling outward.
4. Tip your hips back and bend your knees, lowering yourself into a wide-leg squat, again making sure your weight is on your heels, your knees in line with your toes without extending over them.
5. Press back to standing. This is one full repetition.
6. Step back to a narrow-leg position and continue the 15 repetitions.
7. Rest 30 seconds between sets.

2. Staggered push-ups: 2 sets, 12 repetitions per set

1. Place a low platform (like two thick books) on the ground to one side of your body.
2. Place your palms on the ground beneath your shoulders, but slightly wider than shoulder width apart, one palm on the low platform.
3. Step your legs out behind you into a full push-up position, or lower your knees to the ground for a modified push-up. Make sure your body forms a straight line from head to knees or head to toes.
4. Bend your elbows and lower yourself toward the ground, stopping a few inches before your chest touches down. Your elbows should bend back and out at an approximately 45-degree angle.
5. Press yourself back to the starting position and continue the set.
6. Rest 30 seconds between sets, then perform your second set, this time with the opposite hand atop the low platform.

3. Side lunge: 4 sets, 12 repetitions per set

1. Start standing with your feet shoulder-width apart, your knees slightly bent.
2. Step your right leg out and to the right several feet, so your right foot is positioned slightly in front of your body, your toes angled outward.
3. Keeping your left leg straight, bend your right knee, tracking your knee in line with your toes but stopping before your knee extends past your toes.
4. Press through your right heel, and return to standing. This is one repetition.
5. Continue performing all repetitions for the first set on the right side of your body.
6. Rest 30 seconds, then perform the second set, this time focusing on the left side of your body.
7. At the end, you should perform two full sets per leg.

4. Reverse fly: 4 sets, 12 repetitions per set

For this exercise, use canned goods, water bottles or dumbbells as weights.

1. Hold a weighted object in each hand at your sides, your knees slightly bent and your feet together.
2. Keeping your lower body steady, tip forward from the hip, your torso straight. Allow your arms to dangle down naturally from your shoulders, your palms facing each other, your elbows slightly bent.
3. Maintaining this arm position (mostly straight with a slight bend at the elbows), squeeze your shoulder blades together as you draw your arms up toward the ceiling, stopping when the weighted objects reach shoulder-height.
4. In a controlled fashion, lower the weights back to start. This is one repetition.
5. Rest 30 seconds between sets.

5. Plie squat calf raise: 3 sets, 15 repetitions per set

1. Step your feet out wide to each side of your body, your toes angled outward.
2. Keeping your torso upright and centered between your legs, bend both knees and lower your butt toward the floor, making sure your knees track in line with your toes without extending over them.
3. Holding this plie-squat position, press through the balls of your feet and lift your heels from the ground. Hold steady for one second, then lower both heels to the ground. This is a balance challenge, so if it’s too hard, lift one heel, lower it, then lift the other and lower it. This is one repetition.
4. Perform all repetitions for each set, resting 30 seconds between sets.

6. Dive bomb push-ups: 2 sets, 10 repetitions per set

This is a challenging exercise. Feel free to lower your knees to the floor to perform a modified version.

1. To get into the starting downward dog position, situate yourself in a push-up position, palms beneath shoulders, legs extended behind you. Press your hips up to the sky so your body forms an inverted “V.” Your heels do not have to touch the ground — your weight can be on the balls of your feet.
2. Bend your elbows outward and carefully begin lowering your head toward the ground.
3. Before your head touches down, arch your upper back slightly and press your head forward between your palms, as though you were in a low push-up position with your butt pointed up into the air.

4. Carefully continue extending your body forward until your hips are in line with your knees and shoulders, your palms directly under your chest.

5. If your knees aren’t already on the ground, you have the option to lower them now or to keep them lifted a few inches from the ground.

6. Press through your palms and push your chest up and forward as you arch your back until your elbows are fully extended. (If you can’t extend your elbows fully, just press up as high as you can.)

7. From this position you can return to downward dog by lifting your hips and pressing them back up toward the ceiling. This is one full repetition.

8. Perform one set, then rest a minute before performing the second set.

7. Triceps kickbacks: 4 sets, 15 repetitions per set

For this exercise, use canned goods, water bottles or dumbbells as weights.

1. Hold the weighted object in your right hand.
2. Stagger your legs, your left in front of your right, hip-distance apart. Bend your left knee, keeping your right knee straight, and lean forward at the hips, placing your left elbow on your left thigh for support.
3. Hold your upper right arm directly next to your right side, with your elbow bent at 90 degrees, your palm facing inward.
4. Keeping your upper arm fixed to your side, extend your elbow behind you, tightening your triceps as you extend.
5. Bend your elbow to return to start. Complete the first set, then switch immediately to perform the second set with the left arm.
6. Rest 30 seconds after the second set, then perform the third and fourth sets in succession.

8. Biceps curls

For this exercise, use canned goods, water bottles or dumbbells as weights.

1. Stand with your feet together, your knees slightly bent, a weighted object in each hand.
2. Allow your arms to extend at your sides, your upper arms fixed to your body, your palms facing away from you.
3. Keeping your upper arms steady, bend your elbows and draw the weighted objects all the way to your shoulders. Reverse the movement and lower the weights.
4. Rest 30 seconds between sets.

More four-week fitness challenge workouts

Week 1: The baseline workout
Week 3: Enhance endurance
Week 4: Improve flexibility