Conversation so far:
When did Jerry lewis first fall ill?
Jerry Lewis revealed in the 2011 documentary Method to the Madness of Jerry Lewis, that he suffered his first heart attack at age 34 while filming Cinderfella in 1960.
What caused Jerry Lewis' illness?
Lewis suffered from a number of chronic health problems, related both to aging and a back injury.

Question: How did he hurt his back?
Self-contained rewrite: How did Jerry Lewis hurt his back?