One of the most important arm muscles is the triceps brachii (the triceps, for short). You use your triceps to extend your arm. It opposes the biceps muscle, which is used to flex the arm. You also ...

If your arm day training session is stuck in the same old slog of biceps curls to triceps pressdowns—then wash, rinse, repeat—it's far past time that you introduce some variety into your workout. Take ...