. . . in most circumstances if your lifting with your upper body your doing it wrong . . . your legs are much much stronger.
As basically everyone is able to lift their own body weight with their legs, it's upper body strength that is the more reliable indicator.
If you think that then take a look at the gap between bricks & see just how much of your hand can actually grip it (& people climb on much smaller hand holds). I don't care how much upper body strength you have, fact is your never going to be able to lift much of your weight with your finger tips. You can only climb this sort of stuff because the bulk of your weight is shifted to the points of your toes. Anyways, it kinda irrelevent in both the fact that dwarf fortress doesn't divide upper/lower body strength & that your more interested in discussing the equipment side of things.
So, I take it nobody out there has an opinion on clothing / armor having an effect on their dwarves deciding to go for a casual jaunt down the shaft of a volcano?
I'd certainly like to see equipment weight factored in (if it isn't already). In terms of shoes/gloves:
1. Metal boots are an obvious issue - no flex & you want to be lifting at the heels to put your weight on your toes. Trouble is it's the opposite situation if your climbing in crampons (your better off with a rigid shoe).
2. Leather boots are actually going to be better for climbing then bare feet
if they're shaped for climbing (similar concept to ballet shoes, they pinch at the toes & shift your weight forwards onto the points of the toe)
3. The silk gloves in your example have a problem too, in that they're a smooth material and are going to slide on rock.
4. Gloves/Gauntlets become far less relevant if you climb with an ice axe or equivalent for trees/rock.
Not deliberately trying to be argumentative, more pointing out that if your making it more complicated for realism it's actually going to get fairly complicated particularly if your using climbing gear or boots designed to climb in. And if you just want to stop dwarfs from climbing surely it makes more sense to just allow people to turn climbing off on a dwarf?
Edit: If your climbing in inappropriate shoes/gloves & carrying a backpack, why aren't you taking the things off??