I'm unable to crawl; can't even kneel because of awful knees (arthritis, the x-rays are scary). Had surgery on one when I was 17 so there's no cartilage there at all.

I'd have to 'crawl' on my rear end, pushing myself along with my legs and arms. I assume I can still do that, but I haven't tried in a long time.

Rick, the article really said it was a trick? Doesn't jive with the abstract.