Students continually ask me how to get their forearms bigger. After I briefly explain how the forearm isn’t a muscle that can hypertrophy easily, I offer a more practical option. The hammer curl is a great exercise for the brachialis, or brachioradialis muscle. This muscle, similar to the bicep brachii, assists in elbow flexion. The difference is that the brachialis crosses the elbow joint and inserts at the forearm. The change in muscular insertion point means that different exercises will engage the muscle better.
A great exercise for the brachialis, and therefore the forearm, is the hammer curl. This exercise is performed similar to the regular bicep curl except that your hands are neutral. A neutral grip is when your arms are at your side and your palms are facing in. With this grip, executing the hammer curl will properly engage the brachialis.
So next time you want a good exercise to help strengthen the forearm, avoid excessive wrist curls and try the hammer curl. This will surely get the job done.