EMPLOYEE WAS TO SWITCH 5"" HOSE FROM 600 TO 900. HE LOOSENED EARS OR LOCKING DEVICE ON HOSE. HOSE HAD SOME BACK PRESSURE ON IT CAUSING HIM TO LOSE HIS GRIP ON HOSE. HE GOT OFF BALANCE AND FELL TO THE FLOOR AND HOSE END FELL ON HIS RIGHT FOOT/ANKLE AND LEG.