When you need to carry materials inside the house or in the workplace, it's seldom advisable to use brute strength in handling them. Not only will it require large amounts effort on your part, it's also the easiest way to end up with a strained muscle and a dislocated disc.
Instead of lifting heavy materials yourself, try using a handcart. You do the math. Even if you're an unusually strong guy, carrying 200 lbs of load over a couple of meters will likely be too strenuous. With the right handcart, you can haul ten times that (even more if you use heavy-duty, industrial-grade ones), all while minimizing the risk of even the slightest injury. It's a very straightforward choice - one is easy, the other one's difficult. Which would make for a better pick? Hmmm....
Reduce Lifting To A Minimum
Using a handcart will reduce lifting to a minimum, restricting it to times that you're loading materials onto a platform or hoisting them over a top shelf. Since it doesn't completely eliminate physical exertion, you'll still need to do your usual preparations.
As with lifting without the help of handcart, it's advisable to warm up (to prepare your muscles), be selective about what you carry (don't force yourself to pick up anything beyond your capacity) and observe other precautionary measures. You can ease up, though, since you won't have to expend so much energy manually exerting yourself.
Platform Trucks Vs. Hand Trucks
Which is better to use when trying to avoid back injury, a platform truck or a hand truck? The answer can vary, depending on the kind of lifting you will need to do.
If you're lifting crates stacked on ground level and delivering it to a similar position, a hand truck will completely eliminate any unassisted carrying. With a low platform that's touching the ground, you can simply slide it under the materials. Of course, you'll need to exert some effort while transporting them, mostly to keep balance, lest you'll have them falling over.
Platform trucks, on the other hand, should work great if you have more than one person around who can help both load and unload items. Whether you push it or pull it, effort exerted during transport is kept to a bare minimum, with manual lifting only necessary at the start and end points.
Will Injury Be Eliminated?
Can handcarts prevent all possible injuries? Probably not. Regardless, they minimize the possibility of accidents enough that they can foster an immensely more efficient and safer process of transporting materials within small areas. I'm sure even your doctor will approve.