EMPLOYEE WAS ASSISTING WITH THE UNLOADING OF COAL/COKE FUEL CARS AT THE QUARRY LOCATION. HE ATTEMPTED TO CLOSE A RAILCAR DOOR USING HIS RIGHT FOOT TO PERFORM THIS TASK. HE PLANTED HIS LEFT FOOT & WHEN HE RAISED HIS RIGHT FOOT HIS KNEE BUCKLED RESULTING IN A STRAIN. EE HAS BEEN OFF WORK SINCE ELECTING TO TAKE A VACATION. Dr. SAID HE COULD RETURN 5/2/04 UNRESTRICTED.