Some people don’t know the best way to lift things. Bending down with straight knees to lift a heavy weight such as a shopping basket, or a two-year-old who wants to be carried, puts extra pressure on the back at its curves which are its weakest points, crouching down with bent knees is much safer, and enables you to lift heavier weights, too.
People often expose their backs to needless strain by not studying their working conditions. Women in particular suffer this way because their kitchen surfaces are the wrong height for them. Far too many kitchens are designed for the under-five-foot-five, so- called average person and the thousands of women who are around five-foot-seven or more and who have to use these kitchens feel the result in their backs.
Some people sleep on soggy beds that give no more support than a string hammock. Hours spent in such a surface strains back muscles and ligaments quite severely. A firm bed surface is much healthier.