Curls are the classic gym bro exercise, and a bicep flex is the most iconic way to, literally, flex on someone. But does it matter what type of curls you do? And are there non-curl ways to get some guns? Let’s break it all down.
What the biceps are and what they do
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When we speak of “the biceps,” we usually mean that muscle in the upper arm that flexes your elbow. Technically this is the biceps brachii, meaning the two-headed muscle of the arm. (We also have a biceps femoris, which is one of the hamstring muscles. Femoris refers to the thigh; brachii refers to the arm.) I’ll just say “biceps” in this article, with the understanding that I’m talking about the ones on the arm. And, technically, this single muscle is called “the biceps” but every gym bro uses “bicep” as the singular.
The bicep is considered a two-headed muscle because it starts as two separate attachment points on the shoulder. The short head originates on the coracoid process of the scapula, and the long head on the supraglenoid tubercle of the scapula. That’s right, both parts of the muscle start on your shoulder blade. Weird, huh?
The two parts converge somewhere along your arm. (In some people, you can see a groove between the two heads; in most of us, it just looks like one lump of muscle.) This muscle has a single attachment point on the forearm: on the radius, one of your two forearm bones.
That means the bicep not only bends your elbow, it also supinates your hand (helps you to turn your hand palm-up) by pulling on one of your forearm bones but not the other. It can also help us to raise our arm at the shoulder, but we have other shoulder muscles that do that job better. You can make the case that the bicep is mainly a forearm supinator, secondarily an elbow flexor, and also contributes to shoulder stabilization.
Bicep-focused exercises don’t only work the biceps, by the way. We also have a muscle called the brachialis that lies underneath the bicep and also helps to bend the elbow. It’s actually our biggest elbow flexor. But working the brachialis still makes your upper arm bigger, since both muscles are stacked on top of each other. Which means you don’t actually have to keep track of the difference; just bend your elbow and you’ll get bigger guns.
The best bicep exercises to get started: curls
Curls are classic for a reason. No matter the type of curl, you hold a weight in your hand, and bend your elbow, bringing your hand upward toward your shoulder. That’s it, that’s a curl.
But of course there’s more than one curl in the world. You can curl with different types of weights or resistance (cables or bands, for example), and you can set up the curl in different positions. In this section I’ll go over the most basic types, but feel free to ask around; everybody has their own favorite curl.
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Dumbbell curls: Hold a dumbbell in each hand, palms facing forward. Bend your elbows to curl the dumbbells up toward you. You can do one arm at a time, or both at once. You can keep a neutral grip (hammer curls), pull the weight across your body (cross-body curls), or even point your palms downward (reverse grip curls). But a supinated or hammer curl will be the most common.
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Barbell curls: Hold a barbell in both hands, and curl it upward. This can put stress on the wrists, so play with narrow and wide hand placement to see what works best for you. If you can’t make that work, this is what EZ-curl bars are for. They’re the ones with the wiggly handles.
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Cable curls: Use a cable machine, with the pulley set low, near the floor. You can use almost any attachment, but my favorite is the rope, for a sort of hammer curl grip. There’s often an EZ-bar attachment as well; that’s another good pick.
The most “optimal” bicep exercise: Bayesian curls
I’ve pointed out before that optimal is optional—overthinking the details of exercise doesn’t necessarily get you better results. But sometimes it’s fun to figure out what is the best exercise, at least in theory, and give that one a try.
If this appeals to you, I’d recommend Bayesian curls. This is a type of cable curl that stretches the bicep muscle at the shoulder. You set up with the cable machine behind you, so that you feel a slight stretch at the shoulder at the bottom of the movement. Curl the cable handle upwards, and to really commit to the movement, lean your torso forward as you get to the top of the curl. Here’s a video where Menno Henselmans explains the movement and shows a few examples:
This setup lets you train the bicep at a long muscle length (i.e., when it’s stretched) and arguably puts the most tension on the muscle, giving it the greatest stimulus for growth. Now, is this going to matter very much in the long run? Eh, maybe, maybe not. But it looks cool and gives you a new option besides the same old dumbbell and barbell curls.
The best bicep exercise for people who don’t have time for bicep exercises: chinups
Biceps are small muscles, and so most of the targeted work we give them will be isolations. But they’re also involved in compound pulling movements. Most rowing and pulling motions will use your biceps at least a little, so you can get a lot done just by making sure to include these in your routine.
If I had to choose one compound for biceps, it would be chinups. (There are plenty of internet arguments about chinups versus pullups, in all their variations; in truth the differences are not huge.) But you’ll feel the chinups in your biceps more, and that’s often what we’re looking for so that we can leave the gym feeling like we got a good arm workout in.
Chinups are the exercise where you grab a bar with your arms facing you, so that you’re dangling from it, and you pull yourself up until your chin is over the bar. Your grip should be shoulder-width or a bit narrower. If you can’t do chinups with your body weight, it’s OK to use a band or a box to support some of your weight. And if chinups are easy, add weight to them with a dip belt! For bonus points, hold each rep for a few seconds at the top.