That’s exactly the thing to me, the fastest runners always seem to be feeling the best. I see plenty of people who sign up for ultras and basically struggle through it by willingness to suffer instead of fitness; I see no value in that. I’d rather run a 10k or half really fast and feel amazing than drag myself through an ultra and be miserable, so that’s my training goal.

Theoretically, if you know how to race, you’ll always be hitting the same relative level of pain, just for different amounts of time.

Easy runs should be easy though, and hard training runs should very, very rarely cause pain.