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21-Day Arm Challenge

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

21-Day Arm Challenge

After following this 21-day dumbbell arm challenge created by NASM-certified personal trainer Désirée Triolo, not only will your arms look more sculpted, but you'll also 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 consists of five basic dumbbell exercises to target your biceps, triceps, back, and shoulders to build your 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 for each exercise.

Ahead, you can find a detailed explanation of how to do each of the five exercises, followed by the three-week plan. The first step is choosing the appropriate-size weight — Triolo said you want a dumbbell that fatigues your muscles by the end of the last two reps. She suggested beginners start with two-kilogram dumbbells and more advanced lifters go heavier at 7 to 11 kilograms. 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, decrease the weight amount.

This challenge incorporates two rest days per week, and Triolo said, "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," 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 go for a walk, run, bike ride, or hike.

3-Week Arm 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 amount of time per day. After each day's workout, stretch out your upper body with 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 the five different variations.

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