I practiced for the Appalachian Trail with weight on my back, but on the trail, what did me, and others like me, in, after 7-10 days, was being on uneven terrain after having practiced on flat land. Our knees were done in. For a month I crossed streets and went down stairs like I was a hundred years old. Plenty of energy, though. People who rode bikes, their knees were ok.
I practiced for the Appalachian Trail with weight on my back, but on the trail, what did me, and others like me, in, after 7-10 days, was being on uneven terrain after having practiced on flat land. Our knees were done in. For a month I crossed streets and went down stairs like I was a hundred years old. Plenty of energy, though. People who rode bikes, their knees were ok.