Hammer Curl

The hammer curl is a dumbbell curl held with a neutral, thumbs-up grip — palms facing each other the whole way up, like swinging a hammer. That grip change does more than it looks: it shifts a good share of the work onto the brachialis, the muscle underneath the biceps, and the brachioradialis of the forearm, which adds thickness to the arm and builds real grip strength alongside the biceps. It's a natural companion to standard curls rather than a replacement, filling in the parts of the arm a supinated curl under-trains, and it tends to feel comfortable and strong even for lifters whose wrists complain on a straight bar. You can run it with dumbbells or a cable and rope. The main pitfall is the same as any curl: swinging the weight up trades muscle tension for momentum and invites strain. Keep your elbows tucked, your torso still, and control both directions. For thicker, stronger-looking arms and a better grip, it's an easy addition.