The coach is there on the releases and the dismounts so that if the gymnast misses the bar, the coach can 'catch' her, and slow down her fall, to minimize injury (falling from such a height when you have speed is a serious injury waiting to happen). It is a safety precaution, and it is 100% allowed. I'm sure there is a penalty if the coach touches the gymnast while she or he is on the bar, but they will only touch the gymnast if she or he has missed the bar and is falling. It's called Spotting, and it happens in many sports.
There are some gymnasts whose coaches do not stand there; generally, those are the very strong bars workers.
The coaches are only there as spotters when the gymnast is doing a dangerous release move. In case the gymnast misses the bar, the coach can kind of catch her/him and maybe prevent injury. Or they are there to remove an apparatus after the gymnast has used it to mount. Like those little springboards some use to mount the beam.
Gymnastics are dangerous - especially high bars. There have been athletes that have been paralyzed from falling. The coaches are "spotting" their athlete when the do a tricky move, just in case they fall.
It's called spotting. The coaches are there to catch the gymnast or at least break their fall in case of an accident. It is not only permitted, but required.
Why do coaches stand so near to the Gymnast when they are on the High-Bars apparatus when they are performing..???
It especially happens a lot with Chinese and Eastern bloc coaches.
This must be so off-putting to the Gymnast and very dangerous also.
The commentators never give mention to it. And surely cannot be allowed.
It drives me nuts. I feel like screaming at the tv screen
Anyone with thoughts.....!