EE WAS HELPING CARRY 3/8"" BY 4' BY 6' PIECE OF METAL UNDER THE SIB TO MAKE REPAIRS TO A FEEDER. HE FELT A STRAIN TO HIS BACK WHEN HE LIFTED UPWARD ON A METAL. HE WORKED AS SCHEDULED UNTIL 6-10-02 WHEN HIS DOCTOR ADVISED HIM TO REMAIN AWAY FROM WORK AND TAKE THERAPY 3X A WEEK.