EMPLOYEE STATES HE WAS DUSTING THE BELT LINE; AS HE WAS BACKING UP WITH THE HOSE, RIB SLOUGHED OFF UNDER THE MATT CATCHING HIS HEELS AND KNOCKING HIM TO THE GROUND. HE EXPERIENCED LOW BACK PA IN BUT DIDN'T REQUEST MEDICAL ATTENTION UNTIL 7/25/00. HE HAS BEEN PLACED ON RESTRICTED DUTY FOR APPROXIMATELY 2 WEEKS.