Conditioning is the missing potion 99% of the time and we all know that.
Physics on carried weight are clear. I always carry too much. Writing this from the Colorado mountains where we have been day hiking, reminding myself I need to put in the training at home, put less in my pack and carry something to create a third balance point. Using a single tracking pole here, I use my homemade shooting sticks when hunting.
You all have convinced me to get some lighter boots. I like my solid leather vibrams… but used my Oakley desert boots this trip and wow the difference in leg effort.