Many people, especially men, want to grow big arms. And you can't say you've got big arms without sporting a big set of guns (biceps) when you wear a sleeveless shirt. 

So, between barbells and dumbbells, which tool is better for making your arms look great in a sleeveless shirt? Barbells are very useful for general muscular development. But for bicep training, not so much. Why? Let's get straight into it. 

1. Comfort

Dumbbells allow you to train your biceps more comfortably, especially the inner part of the biceps. A straight bar, or even an EZ bar, would not allow you to properly rotate your arm outwards to target the inner part of the bicep. 

Let me explain: You see, like many other muscles in the body, the bicep muscle derives its name from Latin. "Bi-" represents two, and "-cep" is derived from "caput," which means head. So, the bicep muscle has two heads - the long head and the short head. 

Now, it is difficult to comfortably keep your arm in this position with a barbell. Why? A barbell is straight. It prevents your arms from properly facing forward or outwards because they are trying to hold the barbell together. The bar would force your arms in and prevent them from freely rotating outwards.

2. Range of Motion

So yes, I was talking about how barbells do not allow you to properly rotate your arm outwards and perform a curl for the biceps's short head. In the same way, they also limit your range of motion during a curl. The range of motion refers to how far you can stretch or move a muscle during an exercise rep. 

In the pictures below, I mimicked a barbell curl using a mopping stick. And I have also performed a dumbbell curl. You can see that on the dumbbell curl, I can control my range of motion better. But on the barbell curl, the straight bar out in front of me is limiting my movement. Now, this is not to say that the arms must come all the way down on a bicep curl – longer range of motion is not always better. However, having the option could help you control your bicep training and results more easily. 

3. Elbow Flexion and Bicep Alignment

This point is quite closely related to the first one, but it deserves a solo explanation. You see, your elbows are not biomechanically designed to move the way barbell curls force them to. The biggest role of the biceps in the body is bending the elbows - elbow flexion. That's why bicep curls involve bending the elbows but with some resistance (weights - dumbbells and barbells, in this case). 

So, when bending the elbow during a traditional bicep curl, you want that elbow to align properly with the muscle. Here's a picture to show how barbell curls may not align properly with the biceps. 

In the barbell curl I have performed above, you can see that the line of force from the weights (represented by the small red arrow) does not properly hit the biceps (represented by the weight bigger black arrow). The bar is restricting my wrist, preventing it from twisting out properly to match how my elbow feels comfortable bending. This would mean that the resistance from the weight is not applying tension directly to your biceps.

4. Muscle Imbalance

There are many things that cause muscle imbalance, and one of them is not training both parts of a muscle pair equally. Sometimes, during a bilateral exercise (one that engages both sides of the body), like a barbell curl, the stronger side could take over and perform most of the work. That could result in one bicep being bigger than the other. 

How to solve this? Use dumbbells. Start with the weaker side and train to failure. Then, train the stronger side, making sure you don't perform more reps than you did when training the weaker side. This is just another way dumbbells make your arm training better. 

Is There Anything Barbells Have Over Dumbbells in Bicep Training?

Yes. Barbells can help you save time. With a barbell, you'd train both biceps at the same time, and you'd spend less time at the gym. So, if you're really pressed for time, maybe you could use a barbell instead. 

Very soon, I'll devote a post to the best way you can use barbells to train arms as effectively as possible. I mean, your not having time or access to dumbbells should not prevent those guns from sticking out of a plain black t-shirt. You deserve big guns, too. 

What's the Final Verdict?

Dumbbells are better than barbells for training biceps. This is not to say that you won't get gains if you use barbells. It just means that dumbbells will most likely get you more gains. Also, they'll help you get gains more safely. In summary, in comparison to barbells, dumbbells are safer and more optimal for bicep growth. 

So, next time you have the option of using either dumbbells or barbells to train arms, I hope you choose the dumbbells. Enjoy the gains! 

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