SITTING ON BOTTOM WITH FEET AGAINST BELT, PULLING OUT BELT PIN WITH CHANNEL LOCKS. FELT A BURNING SENSATION IN BACK WAS TREATED AND RELEASED WITH TORN MUSCLE IN BACK AND TOLD TO REMIND OFF WOR K 1 WEEK. RETURNED TO WORK 4-22-02. WORKED 2 DAYS AND EXPERIENCED PAIN IN BACK. OFF FROM WORK AGAIN 4-25-02.