The amount of time your muscles are working against a load is known as time under tension. This is a powerful and effective tool that encourages muscle building, according to the International Sports Sciences Association.
One way to build muscle is with the 21 training method, which uses partial reps and a long time under tension. The goal is to complete 21 reps of each exercise by breaking them down into 3 parts consisting of 7 reps each at different angles during each rep set.
If you were doing biceps curls, for example, you would do 7 reps of top-range partial biceps curls where you only lower your dumbbell halfway, 7 reps of lower-range partial curls stopping halfway up, and then finish with the full range of motion for 7 reps.
Start by doing 3 reps of each exercise, then move on to 7 reps, and finish with 20 reps. Are you ready to get started? Grab a pair of dumbbells and get ready to build some muscle with the 3-7-20 workout! This workout involves doing 3 reps of each exercise, then 7 reps, and finishing with 20 reps.
Try This 20-Minute Full-Body Dumbbell Workout
Do: Perform 21 reps of each exercise following this pattern:
- 7 reps of the bottom half of the exercise
- 7 reps of the top half of the exercise
- 7 reps of the full range of motion
Rest one minute before moving onto the next exercise.
Repeat the walk 2-3 times to hit the 20-minute mark.
Tip
- Hold a dumbbell in each hand with your palms facing each other and hold them in front of each shoulder with the elbows close to the body.
- Push back into the hips and keep your back straight as you lower into a squat, continuing to hold the weights on the front of the shoulders.
- Press both feet into the ground to stand up.
- Repeat this squat for 7 reps.
- On the last rep, as you stand, press the dumbbells overhead by straightening your arms.
- Slowly return the weights to your shoulders.
- Repeat the press for 7 reps.
- Now repeat the full range of motion with squat and press for 7 reps.
Move 2: Stiff-Leg Deadlift to Hammer Curl
- Hold your dumbbells with an overhand grip (palms facing you) and in front of your thighs
- Stand with your feet hip-width apart and your knees slightly bent. Brace your core throughout the movement.
- Without changing the bend in your knees, press your hips back until your torso is almost parallel to the floor.
- Pause, then shoot your hips forward, squeezing your glutes tightly to return to the starting position.
- Repeat for 7 total reps.
- On the last rep, once standing, rotate your dumbbells so that your palms are facing inward.
- Curl the weights upward by bending at the elbows, keeping the palms facing in.
- Lower the dumbbells slowly and repeat the exercise for another 7 reps.
- Then do the combo move of the deadlift and the curl for another 7 reps.
Tip
Do not go lower than your level of flexibility and mobility allows and do not round your back; keep it straight for the entire movement.
Move 3: Dumbbell Reverse Fly
If your form is not correct, lower the weight until you can do the exercise with proper form.
Move 1: Squat Press
- With a dumbbell in each hands, bend forward at your hips until your torso is nearly parallel to the floor.
- Set your feet shoulder-width apart. Let the dumbbells hang straight down from your shoulders, your palms facing each other, with your arms slightly bent.
- Keeping your back flat, raise your arms halfway up (about a 45-degree angle to the floor).
- Lower back down and repeat for 7 reps total.
- Next, start with your arms in the 45-degree position, then raise them up so that your elbows are even with your shoulders.
- Lower halfway back down for 7 reps total.
- Finally, repeat the full range of motion — from arms straight down to arms parallel to the floor — for 7 reps.
Move 4: Upright Row
- Hold a dumbbells in each hand in front of your thighs with your palms facing your body. Your hands should be slightly less than shoulder-width apart.
- Slowly raise the dumbbells along the front of your body.
- Pause when the weights reach your waist.
- Lower back down and repeat for 7 reps total.
- On the last rep, when you reach your waist, perform the top half of the move, raising your weights to shoulder height. Your elbows should be higher than your forearms at the end.
- Once the dumbbells are level with your collarbone (nearly touching your chin), pause for a second, then slowly lower the dumbbells to the starting position.
- Repeat for 7 reps.
- Now go through the full range of motion — from weights hanging straight down to weights at your shoulders — for 7 reps.
Move 5: Overhead Dumbbell Triceps Extension
- Stand with your feet shoulder-width apart and one heavy dumbbell held in front of you.
- Raise the dumbbell above your head until your arms are stretched out straight overhead.
- Slowly lower the weights back behind your head, being careful not to flare your elbows out too much. Stop when your elbows are a 90 degrees.
- Press the weight back up over your head and repeat for 7 reps total.
- On the last rep, when your elbows reach 90 degrees, continue to lower the weight toward your middle back.
- Press to the halfway point and repeat for 7 reps.
- The complete the full range of motion for the last 7 reps.
Try This 20-Minute Dumbbell Workout for Rock-Solid Glutes
If you're looking to increase your strength, pyramid training is a great option. This workout technique involves decreasing the number of reps you do while increasing the amount of weight you lift.
If you were performing a dumbbell squat, you would start by doing 10 reps with 5-pound dumbbells. Your next set would be 9 reps with 7.5-pound dumbbells. You would continue until you were doing 1 rep with the heaviest weight you could manage with good form.
For the first part of the routine, do 10 reps of each exercise, then take a 30 to 60 second break. Next, increase the weight you're using and do all the exercises for 8 reps, then 6, then 4, then 2. Finally, finish up with 2 minutes of jumping rope.
Move 1: Goblet Squat
- Hold a dumbbell vertically in front of your chest with both hands cupping the dumbbell head. Stand with your feet wider than hip-width apart.
- Push your hips back and lower your butt into a squat until your thighs are at least parallel to the floor. Keep your back straight, chin forward, and weight tight to the chest.
- Pause, then stand back up to the starting position.
Move 2: Stiff-Leg Deadlift
- Stand up straight with feet hip-width apart and knees slightly bent.
- Hold the dumbbells in front of your body with palms facing away from you.
- Push your hips back and bend forward, keeping your back flat and knees slightly bent, lowering the dumbbells to ankle height.
- Slowly return to the beginning position.
Move 3: Forward Lunge
- Stand tall with feet hip-width apart, holding the dumbbells at your sides.
- Take a big step forward with your right leg. Start to shift your weight forward so your heel hits the floor first.
- Lower your body until the right thigh is parallel to the floor and the right shin is vertical. Both knees should be at 90 degrees.
- Press into the right heel to drive back up to the starting position.
- Do all your reps on one side before switching legs.
Move 4: Basic Deadlift
- Hold the dumbbells at your sides with an overhand grip (palms facing the body).
- Hinge forward at your hips, bending the knees slightly, lowering the dumbbells to the ground without allowing your back to round.
- Brace your core and lift back to the starting position.
Move 5: Front Squat
- Stand with your feet shoulder-width apart and your toes pointed out 10 to 30 degrees. Place one end of the dumbbells on your shoulders.
- Keeping your body upright and your upper arms parallel to the floor, brace your abs and lower your body until the crease of the hip drops below the level of the knee by pushing your hips back and bending your knees.
- Pause at the bottom, then drive your heels into the floor to return to the starting position.
Tip
Keep your heels on the ground throughout the entire movement.
Move 6: Reverse Lunge
- Stand up straight with feet hip-width apart while holding a dumbbell in each hand.
- With your right leg, step backward approximately two feet from your left foot. Lower your body, keeping your torso upright and taking care to keep your balance.
- Drive through your back foot and return to the starting position.
Move 7: Jump Rope
- Start with the rope behind you.
- Swing it up over your head and bring it back down to your feet.
- Jump before it hits your feet and repeat.
Here's The Breakdown
Time: 20 minutes
Equipment: Mat
Good for: Full body-toning
Complete as many reps as possible during the prescribed time while maintaining proper form. Rest where noted before continuing on to the next exercise.
1. High Knees
Start with your feet on the mat and your right knee lifted to hip height. Bring your left elbow forward and your right elbow back. Return to the starting position, then repeat on the other side. Continue alternating sides and speed up for an added challenge. Complete as many reps as possible in 30 seconds.
2. Butt Kicks
To do this exercise, start by standing with your core engaged. Then, bring your right heel up to touch your right glute. After that, bring your right foot back down to the ground and repeat the process on your left side. Continue alternating sides until you have completed as many reps as possible in 30 seconds. If you want an added challenge, you can speed up the process.
3. Jumping Jacks
Stand up straight with your hands at your sides and jump forward so your legs are slightly wider than hip-distance apart while bringing your hands up overhead. Jump back so your legs are together again and your arms are at your sides, then repeat. Do as many reps as possible in 30 seconds, then move on to the next exercise.
4. Inchworm Walkouts
To begin, stand up straight. fold forward, keeping your legs straight (you can bend your knees slightly if your hamstrings are tight). Next, walk your hands out until your shoulders are over your wrists and your body is straight. After that, walk your hands back towards your feet, keeping your legs as straight as possible. Finally, return to standing. aim to complete as many reps as possible in 30 seconds, and then move on to the next move.
5. Lateral Bear Crawl
This exercise is a bear plank with lateral movement. Start by placing your shoulders over your wrists and your knees under your hips. Hover a few inches off the mat. Move your hands and feet to the left for three steps, keeping your hips stable. Keep your head in line with your tailbone, and your knees lifted off the floor. Do not let your feet or hands cross. Move your hands and feet to the right for three steps. Complete as many reps as you can in 30 seconds, alternating directions. Then continue to the next move.
6. Alternating Side Plank
To do this move, start by getting into elbow plank position. Your shoulders should be over your elbows, and your feet should be hip-width apart. Next, rest on the backs of your feet and rotate your right arm up towards the ceiling. This will open up your chest. Once your right hand is back down on the ground, switch sides. Repeat this process for as many reps as possible in 30 seconds. After that, move on to the next move.
7. Bodyweight Squat
Stand with feet hip-distance apart, toes pointed out slightly. Keep the head in line with the tailbone and sit while shifting hips back. Lower until thighs are parallel with the ground. Drive up through the heels to standing and repeat. Complete as many reps as possible in 45 seconds, then rest for 10 seconds. Proceed to the next move.
8. Pushup Hold
Place your shoulders over your wrists and your feet hip-distance apart to begin in plank position. Maintain a straight line from your head to your heels as you lower your body down and hold in place about 6 inches above the mat. To press back up to plank, drop to your knees. Complete as many reps as possible in 45 seconds. Rest for 10 seconds, and then continue to the next move.
9. Triceps Dips
Start by sitting on the ground with your stomach facing upwards, your fingers pointing towards your toes, and your feet lifted about 6 inches off the ground. Put your weight in your arms, then keep your core engaged as you alternate between bending and extending your arms. Your elbows should be pointing backwards the entire time. Complete as many reps as possible in 45 seconds. Take a 10 second break, and then continue to the next move.
10. Quick Feet
To do this exercise, start by standing with your feet wide apart and your hands out in front of you. Bend your knees and keep your core tight. Quickly alternate moving your right and left feet a few inches off the ground. Do as many reps as you can in 45 seconds, and then rest for 10 seconds before moving on to the next exercise.
