Over time, yes, absolutely. Ankle, spine, and back injuries are super common.
I thought this fad had died off. It seemed to gain popularity about 4 or 5 years ago, but I haven't heard about anyone doing lately. It looks like Type 3 fun; it's not fun to do and it's not fun to talk about later.
You can get a used USMC ILBE pack pretty cheap on eBay. They're designed by Arc'Teryx, are about 85 liters (enourmous expedition size), and weigh about 9lbs. For comparison, my pack is 48 liters and weighs under 13lbs when completely loaded (not including food and water).