Smith Behind-Neck Press

The shoulder press is an exercise that works all three heads of the deltoid (but not to the same extent). This is the deltoid muscle responsible for raising the upper arm. In the behind-the-neck press, the barbell is brought from/to behind the head instead of in front of it. When performed on the Smith machine, the barbell follows a fixed movement path.

The pectoralis major assists in raising the arms. This particularly involves the fibers that run from the clavicle to the upper arm, also known as the upper chest.

In addition to the deltoid itself, various muscles around the shoulder joint are engaged to stabilize it. These include smaller stabilizing muscles such as the four rotator cuff muscles, as well as the larger trapezius and deeper muscles that pull the shoulder joint backward and upward.

The triceps play an active role in the arms by extending them, while the biceps have a stabilizing role in keeping the forearms in the correct position. The muscles in the forearms then stabilize the wrist joint to control the bar.

Core muscles such as the abdominal muscles and muscles along the spine keep the torso upright. Depending on the execution (standing, seated with or without back support), their involvement may be greater or smaller.

Smith machine behind-neck press execution

Focus on the elbows and push them straight upward until the arms are almost extended.

Lower your arms back in a controlled manner until your hands are level with your ears.

Repeat.

Smith machine behind-neck press

Muscles involved:

Shoulder joint:

Deltoid
Rotator cuff (subscapularis, supraspinatus, infraspinatus, and teres minor)
Trapezius
Rhomboid
Levator scapulae

Arms

Triceps
Biceps
Forearm muscles

Abdomen:

Rectus abdominis (straight abdominal muscle)
External oblique (external oblique abdominal muscle)
Internal oblique (internal oblique abdominal muscle)
Transversus abdominis (transverse abdominal muscle, "corset muscle")

Lower back and spine:

Erector spinae
Lumbar multifidus
Quadratus lumborum

Smith machine behind-neck press setup

Place a bench with an upright backrest in the Smith machine rack.
Set the lower safety stops of the Smith machine to the correct height. When the bar rests on them and you are seated on the bench, the bar should hang slightly below shoulder height and make contact with the upper back or trapezius.
Place your hands parallel on the bar. Position them approximately wide enough for the forearms to be perpendicular to the bar. Check the markings to ensure that you are centered and that your hands are evenly spaced.

Smith machine behind-neck press technique

Safety:

Use the squat rack! Especially when training alone. Unless you want to call for help when you can no longer get the bar back over your head after the last repetition.

Pain during or after the exercise? Stop the behind-the-neck press. Also try doing more exercises focused on shoulder mobility, particularly exercises targeting the rotator cuff muscles. In this context, consider exercises such as:

Cable shoulder external rotation
Scaption

The three heads of the deltoid

The deltoid-shaped shoulder muscle pulls on the upper arms from three directions. During the shoulder press, all three heads of this muscle are engaged. However, it is primarily the front head (pars clavicularis) that does most of the work, followed by the outer head (pars acromialis). The rear head (pars spinalis) is engaged considerably less.

The shoulder press can be performed in various ways that can shift the load per head, but not by much. In most cases, the front of the shoulder produces three times as much effort as the side, which in turn produces an average of three times as much effort as the rear.

In front of or behind the head?

The behind-the-neck press is quite controversial, with strong supporters and opponents. Due to a lack of data, this discussion cannot yet be settled. There is only one study that performed EMG measurements on one person to measure muscle tension during both variations.

That study shows little difference in peak tension between performing the exercise with the barbell in front of or behind the head. In terms of average tension, however, the behind-the-neck version would be the "winner." All heads show higher average tension, but the difference is greatest in the middle and rear heads.

Opponents then point to the increased risk of injury. The shoulders must be rotated farther externally, which may place too much load on some of the smaller stabilizing muscles of the rotator cuff. However, research on this is lacking.

At most, this exercise can therefore be cautioned against in cases of existing shoulder complaints or limited mobility of the shoulder joint. Due to its higher difficulty, you could also prefer the shoulder press.

Seated or standing

Research has shown that during the standing shoulder press, the shoulders (all three heads) produce greater effort. The researchers point to the additional need for stabilization when the exercise is performed standing. This would mean that the standing version is "more effective" at engaging the shoulder muscles.

Another possibility, however, is that people often cheat during the seated version. The standing version forces you to stand upright so that you do not fall backward. This limits the possible contribution of the chest muscles. On a bench with a backrest, the backrest is often set too far back. The hips are then moved slightly forward, causing even more backward lean. The shoulders then need to exert less effort because the chest, especially the upper chest, can contribute more.

Smith machine, dumbbells, or barbells?

The same study showed that the shoulder press with dumbbells engaged the shoulders (all three heads) more intensely in every case than the version with a barbell in front of the head. Here too, the greater need for stabilization was mentioned as a possible cause.

Besides requiring the shoulder muscles to perform more stabilizing work with dumbbells, the exercise's movement path is also greater. At the top of the movement, the hands can move toward each other with dumbbells, at the point where the barbell exercise has reached its endpoint.

That increased need for stabilization will be absent when performing the exercise on the Smith machine. In general, free weights require more stabilizing work and therefore greater muscle activity. This would make them preferable to machines. Machines, however, enforce a fixed movement path and stabilize the body to a greater extent. This makes it easier to concentrate fully on the main muscles during the exercise.

At a glance