A little tip for making sure the hip is steady while doing the lifting in is to use only your arms. In this way there is a bigger chance for the hip to stay in same position more often during your shooting (standing position). Often we can see a person using the total body while lifting the rifle from the stand to pointing at the target. And many times these shooters varies with their 0-point and then the groupings are bigger then nessesary.
Sometimes the atlethes are not strong enough to lift only with arms and sometimes its just a habbit or they have not learned it. But to make the 0-point becoming more steady, it is important to lock the hip and then just lift with the arms. If not strong enough make sure the atlethe are doing physical training and eventually they become strong enough. And they can practice with less repetation before break until they get stronger.
If it is just a habbit, show them how much difference change in the hip means by twist their hip a little bit (2-3mm) while they are aiming. They see the result thrugh their diopter.
If they dont know it is better to do it like this, then learn them this.
The 0-point has a bigger chance to become more correct during all shots. Good luck