EMPLOYEE WAS WALKING DOWN A HILL BETWEEN THE #5 & #6 ENTRIES. HE STATED THAT WHEN HE STEPPED HIS LEFT FOOT LOST ITS GRIP AND SLID FOWARD. HIS RIGHT FOOT STAYED IN PLACE CAUSING HIS BODY WEIGHT TO BE SHIFTED ONTO HIS RIGHT LEG. THE SHIFTING OF WEIGHT CAUSED AN INJURY TO HIS LOWER LEG.