I've been doing 200 squats a day with a 50 lb pack, plus a 2 mile hike with ~75lbs.
Well, sort of.
I've been trapping small mammals (like mice and voles, with the occasional ground squirrel) on the prairie for the the better part of a month. It's a LOT of gear, hiked to your site, where you 'set' a grid of 100 traps. A full trap bag weighs in at 50lbs. We set 2 grids a night.
The prairie is hillier than it looks!