EE WAS LOADING AN ENGINE STAND INTO BACK OF SERVICE TRUCK WITH A 988 CAT LOADER. THE CHAIN WAS WRAPPED AROUND THE STAND, SLIPPED AND CAME UNHOOKED CAUSING THE STAND TO KICK BACK TOWARDS EE AND HIT BOTH OF HIS LEGS KNOCKING HIM BACK ABOUT 6 FEET. LEFT ANKLE WAS BROKEN AND BONE BELOW LEFT KNEE. RIGHT LEG - LACERATION.