Here’s what you should know:

The standing dumbbell press works best. It activates the delts more than a barbell bench press or a barbell or dumbbell bench press.
The bench press is an exercise for the deltas to the same extent as for the chest. This is especially true with the incline bench press, head up.
Use a specific grip width when you bench press to engage your delts. Use a shoulder-width grip on the incline bench press and flat bench press. When pressing at a 30-degree angle (head up), use the widest grip that does not reduce your strength output.
Don’t avoid standing chin rows. Although many trainers say that this exercise should be avoided, doing it with a wide grip will target the middle deltoid bundles without harming your shoulder joints.
Use a close or neutral grip for pull-ups. This will result in maximum emphasis on the back delt. Building deltas is not an easy task. The deltoid muscles cover your shoulders like a piece of armor, and it is impossible to gain muscle thickness here from front to back with just one movement.

For large deltas, train hard and light.

The delta is traditionally described as an array consisting of three heads – front, middle and rear, but in fact it is a group of 7 separate segments. As for the type of muscle fibers in the deltas, due to the complex structure, it is mixed, so delta training should include work with both large and light weights.

The king of exercises for deltas.

In terms of the overall muscle activity of all three delt heads, there is one exercise that is number 1, and you probably have no idea which one. Saeterbakken and colleagues (2013) studied 4 different types of delt presses and found that the highest activation (15% higher) was on the standing dumbbell press, not on the standing barbell press. So if you only have time for one delt exercise, choose the standing dumbbell press.

Bench press, baby.

The bench press causes very strong activation of the anterior deltas, almost as high as in the pectoral muscles (study by Schik and colleagues, 2010). This is indeed true for the flat bench press, and for the incline bench press with the head up, even more so. The incline bench press exerts the greatest load on both the front and middle bundles of the deltas. There is no need for special technology. Simply use a 30-degree bench incline and a grip as wide as possible that won’t drop your strength (recommendation based on Barnett et al., 1995).

Reconsider the attitude to standing chin-to-chin deadlifts.

For the last decade, this exercise has been avoided, considered the “shoulder killer”. However, as Dan John says, “there are no contraindicated exercises, but there are people for whom they are contraindicated.” So if standing chin rows are bothering your shoulders, it might be because you’re not doing them correctly.

Try using a wider grip or doing pull-ups on a pull-up machine with a rope handle to get rid of the discomfort. Or just don’t raise your arms so high (below chin level). What’s more, wide-grip rows better accentuate the load on the mid delt and reduce it on the biceps and trapezius (according to McAllister and colleagues, 2013).

Training the middle beam of deltas is hard. It is underutilized during heavy compound exercises like the bench press, military press, pull-ups, and bent over rows. In fact, there is only one basic exercise in which the activity of the middle delt is high – standing chin row. We can say that the snatch pull in the truncated version engages the middle delta in the same way. Don’t forget about swings to the sides.

To activate the middle delt, you need to perform a movement in which the shoulder moves away from the body. To the greatest extent, this beam works at an angle of deflection of the shoulder from 60 to 120 degrees. Therefore, for the greatest activation of the middle delta, use swings to the sides, emphasizing the load on the middle part of the range of motion. A popular technique in this case is to use someone else to create overload at the point of peak contraction.

Use rubber loops.

Something slightly modified, but perhaps as effective as the dumbbell version of the side raises, is doing this exercise with rubber bands (statement based on research by Anderson and colleagues, 2010). Such the variant loads the middle beam more precisely in the middle range, in which the activity of this part of the delta is maximum. This also means that the bundle will be in a state of peak contraction under maximum load for a longer time than in the case of working with dumbbells. For training the rear delts, pay attention to the grip when pulling up.

The rear delts are not as stubborn as the middle beams, because they are well included in most complex movements. The back of the delts show moderate activity with horizontal and vertical rows on the machine (study by Botton and colleagues, 2013), but if you want to really “break through” them, then carefully choose your grip in these exercises. Perform chin-ups or pull-ups with a neutral close grip instead of wide grip variations (recommendation based on research by Signorile et al, 2002).

Use reverse wiring on the PecDeck.

The best way to stimulate the rear deltoid bundles is with a decent dose of both basic and isolation training. Research suggests that the pec deck reverse pull is the king of exercise here. However, you can expand the use of this recommendation to include rear delt fly with dumbbells or on the block in your workout.

Specialized delta training program:

Standing dumbbell press, 6*6
Chin row standing with a wide grip, 4 * 8
Wide grip incline bench press, 3*12
Mahi standing to the sides with rubber loops, 3*15
Reverse wiring on the pec deck simulator, 3 * 15