THE EE WAS SUING A 7'3"" LONG BAR 1-3/4"" IN DIAMETER WEIGHING 25 LBS TO POUND AGAINST FEED HOPPERIN ORDER TO UNPLUG FROZEN SAND. AS THE EE WAS POUNDING ON THE BOTTOM INSIDE OF THE HOPPER HE FEL T A PAIN IN HIS LOWER BACK THE EE CONT WORKING BECAUSE HE FELT THE BACKPAIN WASN'T SEVERE. AFTER1 WK THE EE WAS HAVING TROUBLE SLEEPING AT NIGHTDUE TO PAIN SO HE REQ MED ATTENTION THE RESULTA