There are 9 common reasons why you have a big chest and small arms. These are:
- Insufficient Arms Training Volume
- Not Training In The Full Range Of Motion For Arm Exercises
- Arm Training Frequency
- Chest Training Frequency
- Poor Arms Exercise Selection
- Poor Chest Exercise Selection
- Training Too Heavy
- Training Too Light
- Not Eating Enough Protein
Let’s explore these in more detail.

Insufficient Arms Training Volume
When looking to gain muscle mass, it’s important to do sufficient training volume to stimulate hypertrophy.
Most people with small arms aren’t training them enough.
Solution: Increase Arms Training Volume
For most individuals, aim to target both your biceps and triceps with 12-15 total sets per week, using mainly isolation exercises.
Not Training In The Full Range Of Motion For Arm Exercises
This is one of the most common problems I see with beginner lifters.
When doing bicep exercises like incline curls, they fail to fully extend their biceps.
Or when doing tricep exercises like narrow dips, they fail to lower themselves so that their triceps are parallel with the floor.
In both these scenarios, your muscles are under less tension per rep than they should be, so you’re not getting the full benefit from the exercises.
Solution: Use A Full Range Of Motion For Arm Exercises
By using a full range of motion, your muscles will be under tension for longer which will encourage more muscle growth.
You’ll also be recruiting more muscle fibres, which again, can lead to more muscle growth.
Arms Training Frequency
Most people with skinny arms only target their biceps and triceps once per week.
For example, they may do biceps and back on Monday, triceps and chest on Tuesday, legs on Wednesday, and shoulders on Friday.
But by training each muscle only once per week, you’re seriously limiting arm development.
Solution: Increase Arm Training Frequency To Twice A Week
Instead of doing the above workout routine, a more effective way to grow your arms is to train them twice per week.
For example, you could do arms on Monday, chest on Tuesday, shoulders on Wednesday, arms on Thursday, and legs on Friday, and back on Saturday.
This workout routine allows your arms plenty of time to recover between each sessions, and as you’re targeting them twice per week, they’ll experience more muscle growth.
Chest Training Frequency
Another common problem I see is people training chest too often.
While it would be silly to just skip chest day entirely, you also don’t want to be the person who bench presses every day.
Solution: Limit Chest To Once A Week
As outlined in the routine above, by training chest only once per week, you’ll be somewhat limiting chest development while your arms catch up.
Poor Arms Exercise Selection
Gym-goers with skinny arms typically chose the wrong exercises.
While there’s nothing wrong with compound exercises like pull-ups and bench press, they’re not the most effective if you want to maximize bicep and tricep growth.
Solution: Focus On Isolation Exercises
In your arm sessions, I recommend you choose from the following exercises:
- Bicep Curls
- Hammer Curls
- Incline Curls
- EZ Bar Curls
- Skull Crushers
- Close-Grip Bench Press
- Tricep Extensions
Since these are isolation exercises, they target specifically your biceps and triceps, so you know that you’re getting the most from each exercise.
Poor Chest Exercise Selection
If your chest is much bigger than your arms, then you’re likely doing a lot of isolation exercises like chest flyes and pec dec.
While these are great for chest development, they won’t recruit your triceps which is partly why you have small triceps.
Solution: Focus On Compound Exercises
In your chest sessions, I recommend you choose from the following exercises:
- Bench Press
- Incline Bench Press
- Dumbbell Press
- Push-Ups
As these are compound exercises, they work both your chest and triceps, which means even more work for your triceps!
Training Too Heavy With Arm Exercises
During ego exercises, like barbell curls and close-grip bench press, I often see people doing reps in the 2-5 rep range.
While this isn’t necessarily bad for hypertrophy, it means that you’ll fatigue much quicker and so you won’t be able to train with enough volume to maximize muscle growth.
Solution: Lower The Weight
If you’re the type of guy who is always lifting heavy, then try spending the next few weeks in a hypertrophy phase where you train in the 6-12 rep range.
This will allow for high training volumes to be accumulated, and higher volume often leads to more muscle growth.
Training Too Light With Arm Exercises
This can be an issue for many newbie lifters.
They don’t know how to push themselves properly, so they end up using a weight that they can comfortable get 20 reps per set done.
While I’ve just stated the importance of training volume, there’s a balancing act and too much volume usually means you’re not lifting enough weight to damage your muscles.
And if your muscles aren’t being damaged, then there’s less reason for them to grow
Solution: Increase The Weight
As just covered in my earlier point, you should be aiming for a weight where you can do 6-12 reps per set.
This is enough so that you’re doing sufficient volume, but not too much so that you’re using a too light weight.
Not Eating The Right Foods
When it comes to body composition, the importance of diet cannot be understated.
Many people with a skinny-fat physique with skinny arms and a fat chest tend to eat too many refined carbohydrates, like white bread.
Solution: Increase Protein And Lower Your Carb Intake
By increasing protein, you’ll help encourage arm muscle growth, since protein is essential for muscle gains.
And by lowering your carb intake your body will rely more on its fat stores (from your chest) for energy.
This means you’ll be building your arms more, while toning down your chest.
Conclusion
In summary:
- Small arms and a big chest is usually the result of not training your arms properly, and training your chest too often.
- Increasing arm workouts to twice per week can help increase bicep and tricep muscle growth.
- Adding more protein to your diet and lowering carbs will help add more muscle to your arms, while toning down your chest.
That’s all for big chest with small arms, but why do you have big legs and a small upper body? Or what should you do if you have big thighs and small calves?
Thanks for reading!
Sources
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7400877/
https://pubmed.ncbi.nlm.nih.gov/27102172/
I’ve been in the fitness and strength training industry for nearly a decade. In that time, I’ve gained 30 pounds of muscle, written hundreds of articles, and reviewed dozens of fitness supplements. As for my educational background, I’m a currently studying for my Active IQ Level 3 Diploma in Personal Training.