EE WAS USING A SLEDGE HAMMER INSIDE THE #2 SILO TO REMOVE (KNOCK OUT) A PIECE OF ANGLE IRON. WHILE STANDING ON A PLATFORM HE REACHED OUT (STRETCHING) TO SWING HAMMER WHEN HE THOUGHT HE HAD PUL LED A MUSCLE. HE CONTINUED TO WORK. HOWEVER ON 2-20-04. HE MISSED WORK TO REPORT TO DOCTOR.