I think our spine was designed to resist vertical compression, like the constant pull of gravity, so I don’t see how that would work.
First, that's just what I heard from some authoritative source. But, without getting into the physics, yes, we're designed to resist vertical compression of course, but take a yard long stick, it will be orders of magnitude easier to break it if you apply force force from both ends, instead of throwing it horizontally straight into the ground. In any event, not that it is likely to happen, but if you are in an elevator that's falling, it would have been nice to have thought through your survival strategy in advance. I say: lie down. And if H Bombs are heading your way... duck and cover!