Seriously, you hurt yourself adjusting gears? I can't believe any mechanic would skip stretching with all the bending over we do. My back would be toast without it.
Guess some folks think stretching is magic armor against all wrenches and bolts. Try telling that to my knee after it gave out from crouching by a tire all day. What good is a hamstring stretch when you're lifting a transmission wrong? But hey, if touching your toes saves your back, more power to you. Just don't act shocked when the new guy tweaks something on his first week.