Lifting— To lift a heavy object, bend the knees, keeping the upper body straight (A). Bending as * in (B) may strain back muscles. Housework — In ironing, cooking or dishwashing, stand erect, with weight on both feet (A). Poor body balance (B) makes chores much harder. Lying Down — When reading on a sofa or in bed, make sure that the back is properly supported (B); a sagging spine (A) leads to a sore back.