Military presses are the real deal for delts — they focus on the target muscle. Behind-the-neck presses direct some of the stress into your lats, rhomboids, teres, spinatus, traps and the rest of your upper back. In other words, your back is taking some of the stress off your deltoids and/or shoulder girdle.
That explains why you are “stronger” with behind-the-neck presses than with militaries: With all of those back muscles stacked on top of each other and pushing upward together, enormous leverage is employed through a more stabilized power plane. That’s fine and dandy for your upper back, but it robs your shoulders of their fair share of the work. The proof is in the fact that about half the arc of your front delts will develop a good burn from behind-the-neck presses, but your lateral and posterior delt heads will be relatively free of fatigue.
More important, behind-the-neck presses twist your rotator cuffs into an unnatural position where they receive adverse torque stress, when their function should be to rotate muscles only into positions from which they can flex properly. This may explain why so many bodybuilders who consistently go as heavy as they can with behind-the-neck presses suffer rotator-cuff problems.
In truth, behind-the-neck presses are not a shoulder-widening exercise at all, nor are they a superior movement for building front-to-back thickness. With the bar behind your neck, your deltoid heads are pulled back and in, carrying the stress behind your shoulders rather than spreading it across the shoulder girdle and distributing it evenly over all three deltoid heads.
ONLY MILITARY PRESSES provide the compound distribution of stresses necessary for overall shoulder width and thickness.
IN PRAISE OF THE MILITARY
The military press is the purest and the most basic shoulder exercise possible. More specific movements, such as various raises, are good for developing individual deltoid heads, and dumbbell presses are excellent for maximizing the size of the deltoid complex, but only military presses provide the compound distribution of stresses necessary for overall shoulder width and thickness. A press behind the neck brings your deltoids inward, but a press with a bar in front keeps your shoulders wide and requires the muscle groups of both deltoids to contract in a compound manner, along with your upper back, traps and upper pecs.
During behind-the-neck presses, the bar is firmly stabilized by both your shoulders and back. For military presses, your shoulder girdle alone is responsible for stability. The result is a more sustained contraction in your lateral and posterior deltoid heads. In short, no muscle in your entire shoulder girdle escapes stress — and development — from a military press.
I suggest that you perform military presses seated with your back braced, then freestanding, in alternate workouts. The former allows you to isolate more power into your shoulders, and the latter builds more total-body strength by requiring every muscle in your body — especially your torso and shoulders combined — to stabilize that heavy bar. It also sends you home with the satisfaction that you’ve weathered a great battle.
This takes me to my final praise of any exercise that brings out the best of effort: It makes you want to eat like a horse. That’s a good sign. More work. More food. More muscle.
