When it comes to carrying weight, I did my share of it in the Marines. I was an aircraft ordnance technician, which is a nice way of saying I loaded bombs and rockets on airplanes. Actually there was a lot of skill and knowledge involved, but often it came down to "humping bombs" which meant muscling things into position on the racks. I still have these sort of Popeye arms while the rest of me has gone to pot.
But I also have knee and back problems that I have no doubt can be traced to making 500 pound bombs, napalm canisters, rocket pods, Sidewinder missiles, and 20 millimeter guns cooperate. I am quite "stove up" on some days .