The triceps comprise 2/3 of the muscle mass in the upper arm, so if you want big arms – work your triceps twice as hard as your biceps. Always work the triceps from different angles, using overhead pulleys, lying flat on your back using dumbbells and straight bars, and seated using dumbbells and straight bars. It’s also important to rotate your hand positioning throughout the workout. By rotating hand positions you will work all sides of the muscle, thus ensuring more complete development, so use a different hand position for each exercise – palms up – palms down – and in the hammer position. And perform at least 12-16 sets. The photos below illustrate the different hand positions.