Well, except that I've tried it both ways. The structural support described by Seejay closely describes how I felt when I was careful to breathe in on exertion and out on release. It seemed to give me strength. Sometimes I would go and try to exercise with him, but I hated it. Not anymore.
With this, however, it makes it easier to lift reeeeaaalllyyy slowly if I'm breathing in and out.

Thanks, Seejay