Ehh? Tough = Strength. Strength = Muscle fibers, the basic cell of the muscle. Therefore the concept of being tough is attributed to the muscles.
Does it help if I say I apply 70% isopropyl rubbing alcohol to my wounds when I'm wounded to clear out the bacteria?
I wouldn't say Strong = Tough.
There's gotta be a reason that Strength and Vitality/Constitution/Endurance are different stats on most RPG's.
Hah. Maybe. My general stereotype is that women deal with a lot more pain than men do in general (cramps, pregnancy) so they've got to be better at it, but are a lot smarter (slash-pedantic) when it comes to small injuries.
I could see a justification for giving male characters +1 STR and females +1 CON.
I think your toughness is less based on how you react to a minor injury when you're standing around doing dishes, and more how you react to a minor injury when you're fighting or climbing or something else where you can't really afford to stop and take care of it. If you can ignore it and keep doing whatever you're doing, that's tough. Then again, if you're walkin around the house and you stub your toe and it's always a huge production, with the wailing and the hopping and the crashing into other things - I'd say that's a good indicator of fragility.
In terms of endurance, I think sprinting speed over 100m vs. end time of a marathon is an excellent indicator. Someone might have a 20% slower time in the sprint but 50% faster in the marathon, showing they've trained more for endurance than short-term power.
That's all theoretical though, I haven't lifted weights enough to tell whether the whole "speed muscle vs. endurance muscle" thing is true. I think there's a very reasonable chance that a bunch of jocks have gotten it wrong by repeating sweatroom myths all these years, but I also think a lot of smart people must have been studying it too and maybe they agree or maybe their studies are being ignored.