Skip to main content

When it comes to arm day, it’s easy to fall into a rut – or not even know where to begin. This 21-day dumbbell arm challenge, created by NASM-certified personal trainer Désirée Triolo, is designed to help you mix things up, pretty much guaranteeing that you’ll feel stronger by the end of the three weeks. Don’t worry if you’ve never lifted a dumbbell in your life; this arm plan was crafted with everyone in mind, whether it’s your first time working out or you exercise regularly.

This dumbbell arm challenge leverages a simple arm workout that consists of five basic dumbbell exercises. The moves target your biceps, triceps, back, and shoulders to build overall upper-body strength. Over the course of the challenge, you’ll increase the number of reps you’re doing of each exercise, eventually working up to three sets of 15 reps of each.

Ahead, you can find a detailed explanation of how to do each of the five arm exercises, followed by the three-week plan. The first step is choosing the appropriate weight – Triolo says you want a dumbbell that fatigues your muscles by the end of the last two reps. She suggests beginners start with five-pound dumbbells and more advanced lifters go heavier at 15 to 25 pounds. If the challenge ever feels too easy (because you’re gaining strength!), that’s your cue to increase the weight of the dumbbells. Likewise, if you find your muscles are fatiguing too early or your form becomes compromised, decrease the amount of weight you’re lifting.

This arm challenge incorporates two rest days per week – because even though it’s a challenge, recovery days are always important. “My professional opinion is to alternate upper-body and lower-body training days to improve your overall fitness level and to avoid creating muscle imbalances,” Triolo says, which is why you’ll see “lower body” listed on the plan. On these days, you can do lower-body exercises (like this dumbbell butt workout) or walk, run, bike, or hike.

3-Week Arm Workout Challenge

Equipment needed: Dumbbells

Directions: After warming up for a few minutes with some neck circles, Cat and Cow, and arm circles, perform all five of the dumbbell exercises listed below for the designated number of reps and sets. After each day’s workout, run through these upper-body stretches.

  • Bicep curl
  • Bent-over row
  • Overhead shoulder press
  • Upright row
  • Triceps kickback

Day 1

3 sets of 8 reps of each exercise

Day 2

Lower body

Day 3

Rest

Day 4

3 sets of 8 reps of each exercise

Day 5

Lower body

Day 6

Rest

Day 7

3 sets of 10 reps of each exercise

Day 8

Lower body

Day 9

Rest

Day 10

3 sets of 10 reps of each exercise

Day 11

Lower body

Day 12

Rest

Day 13

3 sets of 12 reps of each exercise

Day 14

Lower body

Day 15

Rest

Day 16

3 sets of 12 reps of each exercise

Day 17

Lower body

Day 18

Rest

Day 19

3 sets of 14 reps of each exercise

Day 20

Rest

Day 21

3 sets of 15 reps of each exercise

Keep reading for instructions on how to do the five different arm exercises.

– Additional reporting by Mirel Zaman