THE EE WAS PERFORMING THE ""WALK-AROUND"" INSPECTION OF HIS HAUL TRUCK PRIOR TO THE BEGINNING OF THE SHIFT. HE STEPPED INTO THE PARKING DITCH, STUMBLED AND FELL INTO THE LEFT REAT TIRES OF THE T RUCK, STRAINING HIS BACK. HE COMPLAINED LATER OF SORENESS IN HIS CHEST. HE WAS SEEN IN THE ER ON 10-29-01 FOR EVALUATION AND TREATMENT.