Consider this- would a casual 3 mile/4 days a week jogger tell someone who runs marathons regularly that they "get it" when they have a discussion about endurance and breathing and dealing with fatigue at the 20 mile mark while still performing at a high level?
Devil's advocate mode on:
Does this someone really runs real marathons or coach actual marathon runners?
What is his record?
In which races did he participate?
How his trainees perform in marathon races against other marathon runners?
Devil's advocate mode off.