Scott,
Thank you so much for such a comprehensive and well-explained reply. I now recall the dicussion in the book about excessive acidity destroying the aerobic base; I suppose I wasn’t considering the uphill water carries as HIT.
The slight irony is that up until I converted to TFNA, the bulk of my training was Crossfit and HIT – I suppose I was seduced by the whole “free lunch” thing! When I returned to mountaineering at the start of this year (specifically that masochistic version called Scottish Winter Mountaineering – ask Steve) I couldn’t understand why I was literally floundering on winter crag approaches and front-point approaches to climbs, despite many sessions of burpees and thrusters! I now know, courtesy of your book, that I had all but destroyed my hard-earned aerobic base! The good news is that I reckon I’ve recovered my previous fitness, now doing 1 hr 20 min Z1 runs and managing to carry 25% of my BW uphill for 2500ft in the same time (planning to improve on the latter in the coming weeks).
Anyway, once again thank you for such a wonderful training resource and taking the time to patiently answer the questions on the forum.
Kind regsrds,
Simon