Maybe you aren’t familiar with the name for the brachialis muscle, but there’s no doubt you’ve seen it on a well-developed physique. The brachialis is the little round muscle between the biceps and the triceps on the outside of the arm. Building this muscle can help increase the peak of your biceps because it pushes that muscle up.

There are several exercises that work the brachialis. Because it’s positioned underneath the biceps, curling exercises using a pronated or neutral grip can be used to target this small but very noticeable muscle. Here are three great movements for brachialis training:

Reverse Barbell Curls – Place an overhand grip on a barbell with your hands spaced about shoulder width apart. Keeping your elbows in tight against your waist, curl the barbell up focusing on using your forearms to initiate the movement. The pronated grip on the bar will activate the brachialis muscles.

Hammer Curls – This exercise is performed using a pair of dumbbells. With thumbs facing up, curl the weight up while keeping your elbows tight against your waist. Use a moderate amount of weight so you can feel the muscles contracting in your arms at the top of the movement. By using a neutral grip with thumbs facing up, you’ll work the brachialis more than the biceps.

Chin Ups – Although this isn’t often thought of as an arm exercise, doing chin-ups with a narrow grip will work the biceps and brachialis as well as your back muscles. Grab the bar with an overhand grip and space your hands out a little closer than shoulder width. Keeping both elbows pointed forward, pull yourself up until your chin reaches the bar. Flex your arms in the contracted position to work the brachialis muscles.