mathematics wrote:
There's so many different meaning of what makes one race 'harder' than another. Really any elite world-level race will be very 'hard' to win or compete at. Is it harder to win the ITU world champs or Kona?
Or do we mean the hardest course to finish? It's not a tri but something like Big's Backyard Ultra would have to be the hardest by definition, since only one person can finish by rule.
Even within a small category like IM's there's different ways that a race can be hard. Maryland is very flat and very fast, but that means tucking into your bars and not moving or stopping pedaling for 4-5 hours. Personally I'd consider it 'easier' if there were a few small hills along the course to stretch out and get different muscles firing, even though the total time may be 10 minutes longer.
The difficulty of run courses is basically determined by weather. It's uncommon to see tri's with significant elevation gain on the run, at least to the extent that it's the determining factor. Tri's need to be warm enough for the swim in the morning which makes it pretty common to see high temps for the run in the afternoon (one of the many factors for why IM marathons are so much slower than open).
You could get a pretty reasonable guess at the hardest Mdot races by looking at DNF rates. The cuttoff times are all the same even though the courses are faster or slower.
The OP did not say "hardest to win" so that takes out winning world championships etc.
Within IM....I would not say staying aero for 4-5 hours is particularly hard if you have trained properly for that. Granted, any IM is never easy, but in terms of hardest races, a flat and fast course is surely not going to be up there. (with the same caveats that obviously it is hard to win...but you can ride pretty easily and pretty comfortably to finish a course like Maryland in 17 hours.
Third paragraph...now you are on to something! Formosa Xtreme Triathlon....last year the course had 34C temps at sea level and at the summit it was 8C and the wind was howling to the point it was difficult to stand in sections. Altitude on the run? Start the run at 2000m, never go below that, and finish at 3275m with a fair bit of up and down in between to get over 2000m elevation gain on the run. The previous version of the course (not available now due to landslide conditions and road repair in Taroko Gorge) the run began at 1650m elevation and was straight up except for one 4km descent on switchbacks that was actually harder owing to all the climbing before and after. And then factor in the gradient...the last 14km of the run has a 10km section that averages over 10% and peaks at 27% gradient! This is the uncommon course that you are looking for where it is demonstrably harder than just about any course any where, and amongst the few courses that rival/surpass this level of difficulty, it is certainly in the top 5 if not top 3. It's a beast! Come next year, I can help you with the logistics of the race, and we can test your theory that IM Maryland can be hardest! (I mean that genuinely...it's an epic race and if you love challenges and are fit, it's hugely rewarding.) During the the first 3 years with pandemic restrictions, it has been mainly local athletes and we've had a 70% DNF rate. This year we have more international athletes and we can see how they do.
For me...Kona PR is 10:01 (yes sigh, I know how frustrating that number is) and my FXT time was 15:46 which included 45 minutes getting a new tire and fitting it after I slashed the sidewall at km 12 on the bike. 12 athletes finished under 17hours, and 22 finished overall when the time was extended to 22 hours.