What exactly should be felt during hollow holds? I do them a lot because they're such a fundamental position, and although my body is about 3/5 legs and not the best leverage, I have been making progress. I wonder, should I tense the glutes, keep my hands above my head, or what? Should curl my spin to maximize the crunch-like move, or should I keep my body as straight as possible? Any video or picture would be appreciated.
Thanks!