If you've done rep after rep of the same exercise with the same dumbbells for the last several months, you might notice your gains plateauing. But if you don't have access to larger dumbbells, you still have options to get your muscles growing again.
It's all about time under tension. That might sound really uncomfortable, but when it comes to weight-lifting, increasing the amount of time your muscles are working against a load is a powerful and effective tool that encourages muscle building, according to the International Sports Sciences Association.
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One way to do this is with the 21 training method, an "old school" muscle-building technique that 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.
For example, if you were doing biceps curls, you would do 7 reps of top-range partial biceps curls where you only lower your dumbbell halfway. Then you'd do 7 reps of lower-range partial curls stopping halfway up. Lastly, you'd finish with the full range of motion for 7 reps.
Ready? Grab a set of dumbbells and get ready to build some muscle with the 3-7-20 workout!
Check out more of our 20-minute workouts here — we’ve got something for everyone.
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 entire circuit 2 to 3 times, depending on how long it takes you to get to 20 minutes.
If your form is compromised at all, drop the weight amount until the proper form can be executed.
Move 1: Squat Press
- 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.
Don't descend beyond your level of flexibility and mobility and don't round your back; keep it straight for the duration of the movement.
Move 3: Dumbbell Reverse Fly
- 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.