The reverse plank is part of the bodyline drills in my bodyweight training routine. This heart opener may feel uncomfortable for the first few weeks. Heart openers and back bends often feel this way because you’re putting yourself into a vulnerable position. It’s also the opposite of what we do all day (sitting and rounding our shoulders with our chest caving in). The key is to open the shoulders, strive to keep the hips up, flex the butt/abs and breathe.
Update:
I now made a video featuring the 5 bodyline drills, and reverse plank is of course, one of them.