EE WAS WALKING TO A HYDRAULIC UNIT TO ADJUST PRESSURE WHEN HE TRIPPED ON A ROCK. THIS CAUSED HIM TO FALL INTO STEP AT THE HYDRAULIC UNIT. IMMEDIATE INJURY WAS A LACERATION TO HIS LT. LEG. EE STATES HE ""WOKE UP THE NEXT DAY & FELT PAIN IN MIDDLE OF BACK SHOULDER. HE WAS SEEN BY A CHIROPRACTOR 8/13/03. REPORTED BACK PAIN 8/14/03.