The military press is a multi-joint barbell exercise. It involves standing with your feet shoulder-width apart, holding a bar at shoulder height with an overhand grip and pressing it straight up above your head until your arms are straight, while keeping your legs and torso completely still. The military press is mainly a shoulder exercise, but it may help you develop big arms too.
The main muscles worked with the military press are your shoulders. The front portion of your deltoids does the majority of the work, but your middle and rear deltoids also play a role. Your arms do some of the work too. The triceps are involved in the concentric, or upward, phase of the press, while your biceps work to help lower the weight under control.
Compounds for Bigger Arms
Exercises can be classed in one of two ways: isolations, which work just a single muscle, and compounds, which work multiple muscles. The military press is a compound move. The best way to build big arms is to combine heavy compound exercises with higher-repetition isolation exercises, according to strength coach Jim Smith. Military pressing is an ideal way to work heavier compounds into your routine.
The closer together your hands are on pressing movements, the more your triceps are involved. If you want to use military presses to specifically target your triceps, spacing your hands closer together will help. Be warned though that going too narrow puts your shoulders in an unnatural position and could cause undue stress, note the editors of "Muscle & Fitness" magazine. Try taking your hands in just 2 to 3 inches to work your triceps without risking injury.
Military presses can help you get bigger arms, particularly bigger triceps. They won't do too much for your biceps, however, and to optimize arm muscle growth, you also need isolation exercises as well as other compounds, such as chin-ups, rows and bench presses. Start each upper-body session with a military press or bench press for four to five sets of five to eight reps, then add in two to three arm isolations, such as curls, pushdowns or triceps extensions, for two to three sets of 10 to 15 reps each.