It doesn’t really hurt today. This 15 year old international day cab has a very hard clutch. Even the instructor comes out rubbing his leg (he’s in his 50s too).
We’re using it to practice alley docking for about 4 hours at a time, rotating through 4-6 students. You have to ride the clutch during these maneuvers, at least while we’re learning.
Road trucks are a lot easier. They have hydraulic clutches.