EE WAS ASSISTING MOVING A HEAVY ROLLER USING A HOIST AND TROLLEY. THE HOIST TROLLEY IS MOVED USING A CHAIN PULL. IN THE PROCESS OF PULLING ON THE CHAIN PULL EE PULLED MUSCLES IN HIS ABDOMEN AR EA. ON 8/5/03 EE STILL HAD PAIN & WENT TO SEE A DOCTOR WHO EXAMINED HIS ABDOMEN & DIAGNOSED A HERNIA. EE UNDERWENT SURGERY TO REPAIR THE HERNIA ON 8/14/03.