Does this really strengthen the spine. Ive heard this a from a few difference sources and it was in a seinfeld episode. haha i know seinfeld probably isnt very credible in this field but seriously... any thoughts? I actually kinda enjoy sleeping on the floor for like half the night, it makes the second half much more enjoyable and if its doing my body justice, i really dig it. Is this complete bullshit and/or could it do any harm?