The push press behind the neck can be used to focus more of the strengthening effect of the push press on the upper back and reinforce a better overhead position.

Stand with the heels approximately hip-width and the toes turned out, with the weight balanced slightly more toward the heels but the full foot in contact with the floor. Hold the bar on the traps behind the neck as you would for a back squat with your jerk grip. Brace the trunk and squeeze the upper inside edges of the shoulder blades together.
 
Dip by bending at the knees only with the trunk as vertical as possible. There will be a slight forward inclination with the bar behind the neck, but the angle should never change from the start all the way into the overhead position.
 
Maintain your balance and dip to a depth of approximately 10% of your height. Brake as quickly as possible in the bottom and drive straight back up aggressively with the legs to accelerate the barbell upward maximally.
 
As you finish the extension of the legs, push the bar straight up with the arms and lock out in a secure overhead position as you let the heels return to the floor. With the bar starting behind the neck, the trunk angle doesn’t need to change, and the bar should move straight up.
 
Hold forcefully overhead for a moment before lowering for the next rep.
 
Notes
The natural tendency with a jerk behind the neck is to sit the hips back and lean the chest forward in the dip; while the position of the bar does require the trunk to lean forward very slightly, it should never lean any farther forward during the lift.
 
If the knees rebend at all after the initial dip and drive, the lift is no longer a push press, but a push jerk. If the feet remain totally flat during the drive of the legs, the drive is not hard or long enough—the heels will rise at least slightly even with the heaviest weights if the leg drive is adequate. Each rep of multiple-rep sets should begin from a dead stop and the full jerk rack position.
 
Lifters with poor shoulder and/or thoracic mobility may not be able to perform push presses from behind the neck—avoid it if there is any pain or discomfort and you’re unable to press smoothly into position.
 
Purpose
The push press behind the neck eliminates the complication of moving the bar back and the chest forward to establish the overhead position, and allows the bar to move directly vertically, which means it’s easier to achieve the ideal overhead position and balance in the split. This makes it helpful for teaching and remediation, and train better scapular and upper back position and strength overhead.
 
Programming
Sets of 1-6 reps can be used depending on the timing and the specific need. 4-6 reps will help more with hypertrophy and some strength; 3-5 reps will be generally the most effective for strength work and some hypertrophy; 1-2 reps will usually be used for testing maximum lifts but will also improve strength.
 
Variations
The push press behind the neck can be performed with a pause in the dip. It’s also often helpful to combine it with one or more push presses in a complex to train the ideal overhead position and then try to achieve it from the front.