
The seated behind the neck barbell shoulder press is a variation of the overhead press and an exercise used to build shoulder strength and muscle.
Vertical press variations are crucial movement patterns to train and should be incorporated into your workout routines. So, experiment with the variations until you find one that feels comfortable for you to perform and continue to work on it.
That said, behind the neck press variations are often seen as a dated practice since they can put the shoulder in a compromised position, increasing the risk of injury.
If you do not have a fair amount of shoulder mobility, it is not recommended to perform this variation. And even if you do, depending on your reasoning behind the use of this exercise, there may be better variations available for you to use.