I sometimes move from shoulder stand to bridge (and vice versa) during my asana practice. On some occasions, I position my palms or fists on my low back while moving in and out of the postures for additional support. This is not a progression I've encountered in a group class; rather, I discovered it while playing on the mat at home. The progression seems natural and graceful to me, plus I feel strong and in tune with my body doing it. However, I'm not sure if it is advisable from a physiological standpoint to move this way. In your professional opinion, is moving from shoulder stand to bridge (or vice versa) safe?