No shit, remember that finger snap, whipping motion that people started doing that would make the index finger slam into the middle finger and make the group sound like a forest full of muffled Cicadia Bugs? I'll never forget the day that Mark Errett lost his fuckin fingernail doing that shit and it hit Liz Cassidy in the chest and landed in her glass of iced tea!! That particular form of motovating was banned from Milton Roy after that, but could have re-surfaced anywhere. (Actually, it was his band-aid, but it really grossed people out when it flew through the air)
As for back problems, some of that has its roots in psychological behaviors. For me, when I was working at the St. Pete Times, management used Sylvan Mind Control Seminars to train supervisors in better ways to fuck with us and get more productivity out of us. I would in turn "prove myself" to them to keep them off my ass by working way harder than was safe. I would lift more weight, hyper-extend instead of asking for help (which makes you appear to be weak) and all sorts of shit.
It all came to a head one night, when I had a massive back spasm and lay across a stackout of newspaper bundles for about 10 minutes unable to move. I called in, got back, went to hospital, and X-rays showed a lower spine that looked like I was in my '60's. A pinched nerve was causing the muscles to contract to the point that they were pulling my own back out of alignment. It took a shitload of physical therapy, but I got it all straightedned out.
The main thing to remember is that it took bad habits to mess up your back and it will take an equal amount of good motion to cure the back. Every person I ever met with a bad back fixed it through excersise. The ones that did'nt do their excersise still suffer and my attitude is fuck 'em, pussys like that only cause the rest of us to pay higher premiums on our Health Insurance to pay for their candy ass "pain pills" and quack doctor visits.