If you're looking to sculpt and strengthen flabby arms, you'll want to focus on your biceps, triceps, rotator cuff and chest muscles.
These muscles make up your inner arms and are all connected to your shoulder joint, says Michelle Ditto, CPT, training development manager at Pure Barre. Stronger inner arms not only give a more defined and chiseled look, but they allow for better shoulder mobility, particularly when rotating your shoulder toward your midline (middle of the body), also known as adduction.
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"As the most mobile joint in the body, shoulder mobility is key to allowing freedom of movement and less pain when doing daily activities. When you can better maneuver your shoulder through its full range of motion, you are allowing your muscles to optimally function, increasing strength and mobility," Ditto says.
How Do I Build Muscle in My Inner Arms?
It's not possible to spot train flabby inner arms and lose fat in one area of your body. The key is to target particular muscle groups.
What Muscles Make Up the Inner Arm?
In this case, it's the muscles in your arms, shoulders and chest. This will help you build overall strength in your arms and change your body composition over time.
"Focusing on the major movers of the upper body is key; these include your biceps, triceps and chest muscles, also known as your pectoralis muscles, primarily, with some involvement from your shoulder girdle, as well as your rotator cuff muscles," Ditto says.
Your rotator cuff muscles stabilize the shoulder blade in order to better articulate the shoulder joint.
How Do I Tone My Inner Arms?
To get the best results, train these muscles twice a week for 30 minutes, Ditto says. And you can start with this 30-minute upper-body workout below, which involves using a pair of light dumbbells and a long-loop resistance band.
"These exercises exemplify a holistic approach to targeting your arms, utilizing the major muscles of the upper body in accordance with the mobility at the shoulder that allows you to access the inner arm in the first place," Ditto says.
1. Standing Isometric Chest Press
- Hold a light dumbbell in each hand and lift your arms in front of your chest to create a circle. Bring your hands together so that the weights are parallel to each other.
- Keeping your upper arms stable and maintaining good posture, lower your elbows so that the heads of the two dumbbells meet.
- Lift your elbows back up to the starting position.
- As you lift and lower your elbows, think of squeezing the heads of the weights continuously together to engage your chest muscles throughout the movement.
- Do 8 to 12 reps for 3 to 5 sets.
Tip
Remember to keep good posture throughout the exercise by keeping your shoulders down and away from your ears, your chest proud and your neck long.
To make this move more challenging, add two pulses of your elbows toward each other as you lower them down. This adds more muscle engagement of the inner arms, Ditto says.
2. Supinated Chest Fly
- Start standing and hold a light dumbbell in each hand, palms face-up.
- Raise your arms in front of your chest with your elbows slightly bent.
- Maintaining the slight bend in your elbows, open your arms out to the sides. Think of isometrically flexing your biceps throughout the movement.
- Reverse the movement and bring your arms back together. As you close your arms, think about leading with your elbows. This will help you maintain shoulder stability.
- Do 8 to 12 reps for 3 to 5 sets.
Tip
If you lack shoulder mobility, lower your arms slightly and consider a smaller range of motion, Ditto says.
3. Goalpost
- Stand tall with a slight bend in your knees and hold a light dumbbell in each hand. Lift your arms straight in front of you so that the weights are parallel with each other.
- Keeping good posture, bend your elbows so your arms form 90-degree angles and open your arms out to the sides, forming goalposts with your shoulders.
- Reverse the motion, bringing your arms back to the center. As you open and close your arms, lead with your elbows and actively flex your triceps.
- Do 8 to 12 reps for 3 to 5 sets.
Tip
Make this move more challenging by adding an arm extension to the sides once you open your arms. This hones in on your shoulders even more, as well as your lats and biceps, Ditto says.
4. Lateral Reach
- Start standing and hold a light dumbbell in each hand.
- Bend your arms to 90 degrees and open them up to the sides with your elbows at your ribcage.
- Extend your arms straight out to the sides, raising them to shoulder height.
- Reverse the motion and squeeze your elbows back to your ribcage.
- Do 8 to 12 reps for 3 to 5 sets.
Tip
Flipping your palms up will further recruit your biceps.
5. Band Pull-Apart
- Stand with your feet hip-width apart and hold each end of the resistance band.
- Lift your arms straight out in front of you and hold the band at a comfortable width while still feeling tension in the band.
- Brace your core and pull your shoulders back and down to activate your lats and rotator cuff muscles, then pull the band apart as wide as you can while keeping your wrists straight.
- Return to the starting position.
- Do 8 to 12 reps for 3 to 5 sets.
Tip
You can progress this movement by adding an isometric hold. Hold as much tension on the band as you can while maintaining good form.
6. Triceps Kickback
- Hold a dumbbell in each hand and hinge your hips back, maintaining a straight spine. Your upper body should be just about parallel to the floor.
- Keeping your elbows close to your body, extend your arms straight back in a controlled movement and squeeze triceps at the top.
- Slowly lower your arm back to the starting position.
- Do 8 to 12 reps for 3 to 5 sets.
Tip
You want your elbows slightly above your ribcage to engage your triceps effectively while keeping your neck long and avoiding rounding your shoulders forward, Ditto says.
You can lessen the intensity of this move by lowering your arms slightly or doing it with just your body weight.
7. Triceps Dip
- Sit down on the ground and place your hands under your shoulders with your fingers facing forward.
- Press your body a few inches off the ground so you're hovering off the floor.
- Slowly bend your elbows to lower your butt to the floor, then press your hands into the ground to extend your elbows back to the starting position.
- Do 8 to 12 reps for 3 to 5 sets.
Tip
To modify, consider keeping your butt on the floor and bending your elbows from there to take some of the weight out of your shoulders and triceps.
You can make this exercise more challenging by extending one leg to the ceiling (be sure to even it out on the other side), Ditto says.
8. Push-Up
- Get into a high plank with your shoulders over your wrists and your legs extended straight behind you. Squeeze your quads and glutes to protect your lower back.
- Bend your elbows at a 45-degree angle to your body and lower your body to the floor.
- Make sure to keep your body in one straight line from your neck to your hips and down to your heels.
- Press into your palms and push the floor away from you to come back up to a high plank, still keeping your body in one straight line.
- Do 8 to 12 reps for 3 to 5 sets.
Tip
Do an incline or knee push-up to get full range of motion until you build enough strength to do a regular push-up.
Which Muscle Group Is Easier to Gain, Biceps or Triceps?
Most people find that it's easier to build their biceps because you naturally engage these muscles throughout the day, Ditto says. On the other hand, your triceps are the three-headed muscles that make up the back of your upper arm and fatigue more quickly.
"Think about holding anything of weight in your arms, even your groceries or your child. Your biceps naturally flex to do this, whereas your triceps extend (biceps and triceps are antagonist muscles of each other— when one contracts, the other extends)," she says.
"This is not to say that you can’t build muscle in both, but you may need to focus more directly on your triceps to highlight this muscle group."