Hi Mark,

Ok, found it, I knew that I had listened to this recently. Its a podcast with Luke Nelson (https://www.scienceofultra.com/podcasts/81), a very accomplished ultra runner. His aim (approx 9 min into the podcast) was to improve, with the help from his coach, his aerobic efficiency. To do this he spent months at a very low intensity, even when climbing hills — 130 BPM, as you know, that is really low. Could it be worth your guy increasing the really low intensity, for longer duration, to up that aerobic efficiency late in the race. I’d be interested to see what you think. Jeremy