
The behind the neck military shoulder press is a variation of the overhead press and an exercise used to build shoulder strength and muscle.
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.