"How can I hurt my back at work?"

    Easy.  The most successful claimants:

          √  Bend at the back - not the knees

          √  Twist while lifting

          √  Fall on the tailbone

Keep your knees "in the bank."  You can hurt your knees later, after the back case settles. 

If you take out your knees first you might not return to work and get to hurt your back.

Do the math.