Like the title says, when you’re struggling to finish a long run, or you’re feeling really tired on a workout, what part of you is most tired? Does your breathing get labored and your lungs burn? Or your stomach gets really upset? Or do your legs get really heavy and tired? Something else?
I was just wondering because it seems like my legs are always tired when I run and are holding me back a little, because nothing else really gets tired except my legs.