OTHER EE, ANOTHER EE, AND EE WERE INT HE PROCESS OF TRYING TO KNOCK A WEDGE OUT OF A DRUM. OTHER WAS HOLDING A BAR ON THE WEDGE AND EE WAS USING A SLEDGE HAMMER TO HIT THE BAR. ON ABOUT THE TH IRD HIT EE GRAZED THE BAR CAUSING THE HAMMER TO SWING TOWARD OTHER. EE TRIED TO HOLD BACK THE SWING SO THAT HE WOULD NOT HIT OTHER. THIS CAUSE EE TO TWIST HIS BACK, RESULTING IN THE BACK INJU