the posterior latissimus dorsi pull-down is a multi-joint movement, as the shoulder and elbow joints are both active. Therefore, in addition to the back, the pull-down also works other muscular muscles: The posterior shoulder fasciculus, the biceps, the long head of the triceps and the forearms.

pulling the bar behind the neck is a not very good exercise trajectory and may cause injury to the shoulder joint (pulling the bar behind the neck is difficult for the rotator cuff as it causes hyperextension). It is better to pull down in is front of the neck, all the way to the collarbone. In real life or sport, there is not much practical application for pulling the bar behind the head. The contraction of the latissimus dorsi is not as strong as the anterior cervical pull down. Therefore, you should pull the barbell up to your chest, not behind your neck.
Some exercise machines simply cannot pull the bar directly behind the neck, which means you have two options: Either abandon this movement or turn around to face the machine in reverse and abandon the thigh support pads.
The anterior latissimus dorsi and posterior latissimus dorsi pull-down will help beginners develop enough muscular strength to have the power to do forward and reverse grip pull-ups. You can increase the resistance and gradually build strength.

behind-the-neck latissimus dorsi pull-down - proper movement technique
starting position: Sit facing the machine with your thighs under the support mat and hold the bar with a grip wider than shoulder width. Grasp the bar with your arms bent in front of you and bring your torso and head forward (lean forward slightly, keeping your neck and back straight). Imagine that your head is in a straight line with the centre of the bar. This is your starting position.
Perform the movement: Inhale and pull the barbell behind your neck, elbows together with your body. Exhale at the end of the movement. Hold the contraction for a moment and then slowly return the bar to the starting position.

additional movement tips
sit on your seat with your feet flat on the floor, arms extended upwards and back slightly forward.
Keep your body stationary throughout the movement. Only the arms should move.
Concentrate on squeezing the back muscles as you lower the bar. As you squeeze the latissimus dorsi muscles to start the movement, tuck in your shoulder blades and pull the barbell to the back of your neck in a smooth motion.
Slowly pull the bar to the back of your neck, but do not let the bar touch your neck.
Maintain correct body position with the chest facing up and the head facing forward.

muscles used in the movement
the behind-the-neck pull-down works the latissimus dorsi (middle and lower back), the rhomboids (under the shoulder blades) and the rhomboids (upper back). The latissimus dorsi, the triangular-shaped muscles that run from the armpits to the sides of the lower back. They are the largest muscles of the back and the only ones that can be seen clearly from the front.
Primary muscles: Latissimus dorsi, biceps (short head), rhomboids
secondary muscles: Pectoralis major (lower lateral), triceps (long head), teres minor.
Rhomboid, brachioradialis, biceps (long head), deltoid (anterior-posterior fascicle)
antagonists: Deltoid, pectoralis major (upper), triceps

movement variations
neutral grip latissimus dorsi pull-down. Use a neutral grip (straight bar with vertical handles or triangular handles) to place the arms in a stronger position. Although you can use more weight, remember that it is your arms that are carrying the extra weight.
Rotate the front latissimus dorsi pull-down. The wrong reverse grip is the easiest pull down because this the best angle for your biceps to fire. The closer your hands are together, the more the biceps are engaged.
Wide grip latissimus dorsi anterior neck pull down. A wider than shoulder grip will slightly reduce your range of motion, but will help you feel the latissimus dorsi better in the movement, with less arm involvement.
Machine pull-down.

alternative movements to the latissimus dorsi pull down
there are many other alternative movements that have the same training effect. Choose one of the following mid-back exercises (latissimus dorsi exercises).
Forward grip pull-ups.
Reverse grip pull-ups.
Assisted pull-ups.
These movements (pull-ups) all train the width of the latissimus dorsi muscles, mainly raising the latissimus dorsi and the large circular muscles. When you work these muscles, they certainly thicken, but mostly expand to the sides, giving the impression of a wider back.

when we started working out, everyone has done the behind-the-neck pull-down at one time or another. But after mastering the anterior latissimus dorsi pull down, the posterior neck version is like an "Abandoned movement". The anterior lat pull is a better movement - research shows that it produces a stronger contraction in the latissimus dorsi - but we also include the posterior lat pull in our training because it is the reverse of the posterior shoulder press. As with the bench press, you should pull down to the same point on the neck each time you repeat the movement and keep the pull cord as straight as possible.

if you lack upper body strength when doing regular pull-ups, this is another strength-boosting move for your back. If you have shoulder problems, you may feel uncomfortable doing this movement, use the anterior latissimus dorsi pull down instead.