We have heard morbid stories of photogs who sufferred serious/permanent injuries from carrying their cam equipments, just like the Chinese newspaper photog (who got a painful spinal injury, and who recovered after receiving some godly advices from a Tibetian monk).
As for me, i have already got a "permanent" left shoulder and left knee problems. It's quite painful at times but when there are photo opportunities, I will still take the pain and go out shooting. I think this is one of the price you will pay when you are carrying the 70-200 F2.8L IS!
Do you have any such experience?
Did you give up the heavy equipments becoz of resulted injuries?
What type of injuries have you sufferred?