When you lift objects like boxes, remember to keep them close. A dirty shirt is better than a clean shirt when it comes to preventing a back injury. IF you lift objects and keep them away from your body, you are putting increased pressure on your arms and back. You do the math!
Lifting a 10lb. object away from your body = 100lb of pressure on your back
Lifting a 10lb object close to your body = 10lb of pressure on your back