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21-Day Arm Workout Challenge

Strengthen Your Arms and Shoulders With This 3-Week Dumbbell Challenge

21-Day Arm Workout Challenge
Image Source: POPSUGAR Photography / Chaunté Vaughn
Product Credit: POPSUGAR 8lb Dumbbells, Nike sports bra, Nike leggings, APL sneakers

After following this 21-day dumbbell arm challenge created by NASM-certified personal trainer Désirée Triolo, it's pretty much guaranteed you'll feel stronger. Don't worry if you've never lifted a dumbbell in your life; this arm plan was designed 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.

  • Hammer curl
  • Bent-over row
  • Overhead shoulder press
  • Upright row
  • Triceps kickback
Day Reps
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.

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