Just a suggestion. Put 100 lbs un a ruck sack, strap to back, visit a friend in a condo or apartment, go from 1st floor stairs to penthouse. Rest 10 minutes in between. Go up 3 times.
the building i worked in has 14 floors, I would do the stairs each day (we were on FL 14).
was a challenge at first (kinda old) then improvements came quick. would do it each am when i got there and then again after lunch.
little skinny guy i worked with was a runner, he'd buzz up and down easily. he weighed 130 (twink).
used to tease me at first when i was laboring up (im 205 lbs). so he grabbed a backpack, stuck a few laptops in it and tried it.
world of difference for him. (much harder). I told him ill take my 70 lbs of muscle i have over him, he can keep his great cardio (and bald head).
