For back safety, an average adult should not lift bulky items that weigh more than 25lb (11kg) without assistance. So, instead of packing fewer, bigger boxes full of stuff, fill more, smaller boxes with your moving items. When you do need a bigger box, for instance for an awkwardly-shaped item, fill the rest of it with lightweight items or packing material to keep it under 25lb (11kg). Depending on your physical condition, you might feel confident lifting a box of books that weighs more than this. However, bulky or awkwardly-shaped items, like furniture or home appliances, should be lifted with helpers to reduce your risk of injury. Lift in tandem with your helper or helpers when dealing with the heavy items. Make sure everyone uses proper technique and lifts at the same timetry counting out "1, 2, 3, lift!" Rather than carrying a wardrobe from one bedroom to another on the same level, for example, slide it instead. Use proper lifting technique to tip up one side slightly and slide a sheet of cardboard beneath it. Then, do the same with the other side. From there, you should be able to safely push the item across multiple types of flooring. Push with your legs, keeping your back at its natural slight curve, your head up, and your arms bent. Don't arch your back when pushing. It's easier on your back to push rather than pull. You can also buy moving sliders to place under furniture and other heavy items. Look for them at home improvement stores or online. Basically, any time you can use wheels to your advantage, do so. Hand trucks are great for moving boxes and appliancesyou just need to slide the platform under the item, secure the item in place with the straps, tilt back the handle to lift the item onto the two wheels, and push or pull the hand truck to your destination. Hand trucks are often called dollies, although technically a dolly has a level platform and four wheels (meaning you have to lift the item onto it). You can rent hand trucks and other moving tools from home improvement stores and tool rental stores. If you rent a truck from a moving company, you may also be able to get some moving tools to use. No matter what moving tools you use, make sure you know how to use them properly, follow all safety recommendations, and don't exceed the maximum safe load. If you're not sure how to use something, ask for a demonstration when you rent it. Sometimes the wisest way to protect your back while moving is to let someone else do the lifting for you. If you've had a back injury, have recurring back problems, or have any current or ongoing issues with your legs, core, or arms, don't risk serious injury by trying to lift and move heavy items.

Summary:
Pack smaller, lighter boxes as much as possible. Get help lifting bulky items that weigh more than 25lb (11kg). Don't lift when you can push instead. Use hand trucks, dollies, carts, and other moving tools. Know your limits and hire movers if needed.