THE EE WAS DESCENDING STAIRS AND HIS RIGHT KNEE BECAME WEAK. HE STOPPED AND RESTED FOR A FEW MINUTES AND CONTINUED WALKING TO THE WAREHOUSE. HE STOPPED AGAIN AND PUT HIS WEIGHT ON HIS LEFT LEG BECAUSED HIS RIGHT KNEE BECAME WEAK AGAIN. HE STOOD THERE FORE SEVERAL MINUTES TRYING TO RELAX THE KNEE BUT COULD NOT STRAIGHTEN OUT HIS LEG.