Using a piece of webbing or rope, you can construct a sling to carry heavy loads on your hips rather than back. Here, we're using a loop of climbing webbing to form the sling and carabiners to keep the webbing tight around our hips. The same thing could be done with a length of rope tied forming loops on each end. In the video, you can see how easy it is for us to carry around an old washer, which weighs approximately 150 lbs. Using this same method, we just as easily carried a 267 lbs (according to the manual!) washing machine up two flights of stairs and around our house.
With the weight on your hips, your arms are free to stabilize and open doors. Also, since the force isn't being carried by your arms, your back is out of the equation, and you're much less likely to hurt it. Every time I move a washing machine, refrigerator, or something else heavy using this method, I feel like I'm getting away with something because it's so much easier than I expect.