I came across this web site from the Ontario Government in Canada recently. It had the usual sort of introduction but it was the phrase right at the end of the paragraph that caught my attention. I like it and will no doubt pinch it to use in my sessions.
The paragraph was this:
Every day we use our muscles, tendons, ligaments and joints to lift, carry, sit, stand, walk, move and work in a variety of ways. However, sometimes these tasks or the way we do them can put too much demand on our bodies, causing pain and discomfort. In addition, it may lead to a more serious injury called a musculoskeletal disorder (MSD). Working shouldn't hurt!
There are some useful links relating to the following as well.