Reverse curling means that you do not use an underhand, but and overhand grip and that you perform the exercise with your palms down.
TARGET MUSCLE: NOT THE BICEPS, BUT THE BRACHIORADIALIS
By performing curls ‘inverted’, you turn it into an exercise for your brachioradialis. That’s a forearm muscle that helps your biceps brachii and brachialis in your upper arm bend your elbow. When your forearm is in a pronated position, such as with an underhand grip, the brachioradialis takes over much of the work of the biceps and brachialis.
By the way, the strongest position of your brachioradialis is neutral, i.e. with your palms facing each other, as in hammer curls. Nevertheless, with reverse curls you load them relatively more heavily, because of the relative inactivity of your upper arm muscles.
SHAKING UP THE BRACHIALIS
The brachialis (2 in the figure above) is more involved in reverse curls than in ‘normal’ biceps curls. In addition, you can further increase its role by performing the eccentric phase (lowering the weight) slowly. Research has shown that the brachialis is activated more with slow movement, at the expense of the biceps brachii (1). This is because the brachialis contains more so–called slow-twitch muscle fibers (type I), which contract more slowly than type II muscle fibers (fast-twitch).
It’s the ‘forgotten’ brachialis that almost literally pushes your biceps upwards and gives you peaking biceps. The most effective exercise for this muscle are (slowly performed) hammer curls. But with slow reverse curls you can give them an extra push. Don’t worry about the biceps brachii. After all, you already train them extensively with conventional biceps exercises, as well as with your back training.
Training the brachioradialis and the brachialis ensures a complete muscle development of your arm. Reverse curls are a great, often overlooked exercise for this.
Grab a barbell or EZ-bar with a shoulder-width grip and palms down. Curl the bar toward the top of your chest, keeping your elbows in front of your hips. Make sure to keep your upper arms in place as you curl. Hold the top position for a moment. Then slowly lower the bar to the starting position. Do not pause, but immediately start the next repetition. Exhale as you raise the bar.
You can also do reverse curls with a pair of dumbbells or with a cable.
A good and perhaps even better alternative to reverse curls are Zottman curls. In doing so, you perform the upward phase as a ‘regular’ curl, to rotate your hands 180 degrees at the top and perform the negative phase as a reverse curl. To be clear, you can, of course, only do this exercise with dumbbells.