EMPLOYEE STATED HE WAS PLACING CRIBBING (WOODEN 6""X8"" APPROX. 36"") TO CENTER UNDER THE AXLE. THE CRIBBING HAD TO BE MOVED BACK ABOUT 3"" TO CENTER UNDER THE AXLE. HE WAS SITTING ON A SHORT WORK STOOL WITH LEGS SPREAD, ELBOWS PLACED BEHIND HIS KNEES AND PUSHED THE CRIBBING WITH HIS HANDS AND FELT A POP AND BURNING SENSATION IN HIS LEFT DISTAL BICEP. FIRST LOST DAY 8/13/03.