XC Marathon Pacing

Looking at my first XC Marathon in October (100km/3000m climbing) and trying to find information on pacing - went for a trial a couple of weeks ago and went WAY too hard and blew up early. Lots of advice saying don’t go “too hard” but also that you dont want to leave anything out there. Struggling to find anything really directed at % of FTP or % of HR(Threshold). Is this a way to pace or too hard to use practically? Any direction appreciated…

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At a very basic level that’s a lot of vertical ascent so you’ll need to manage the number and difficulty of climbs, some of which may well force you over threshold to just keep moving forward.

Do you have an elevation profile or a .gpx of the route? That would be a good start for planning.

You could also take a look at best bike split


You’ll also need to carefully manage your nutrition and hydration as I assume you’ll be on the course for 4-6 hrs?

A great link to resources below


Sounds like the Whaka100. :slight_smile: If so I am looking at an IF of around 0.80.


Pacing is highly individual, it depends on fitness level and (realistic) race ambitions.

Front pack paces according to “survival of the fittest”, these days XCM is like XCO, fast starts, survival to the end. You have to go with your competitors. This is also important for mental reasons, it’s “easier” to push yourself in a group.

For Mid/rear pack an even pacing may be more sensible. Depending on fitness level climbs will be taken somewhere between upper tempo to upper endurance zone. If you still have something left in the tank you can always crush the competition on the last two climbs … but quite frankly, almost everyone goes to fast in the beginning, being in the pack, race fever. Difficult to hold back.


Ha! Busted @Jason_Kennedy … thanks that’s really useful to know where to start


Thanks @Jonnyboy I’ll have a look

No problem. I have just got back from RotoVegas after a week or so there and have Recce’d most of the course now. I have a power meter on the MTB and I have noticed i have been around the 0.8 IF for my rides. If I am fitter I think slightly above that is realistic but certainly not above 0.85. It will take me in the region of 8 hours. Best bike split will not work for the Whaka100… it is not your average Marathon MTB route.


I’m mid pack in races like these & always end up riding by myself. I start a bit easy because it takes me a long time to get warmed up. I then ramp up to max effort for the remaining miles of the race. Max effort at 45 minutes is significantly faster than max effort 6 hours, however :rofl:

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It is individual as mentioned. I race XCM and:

a) Aim to stick with the top 20 at the start
b) Ride Z3 most of the way**
c) Climbs are at, but not above threshold.
d) Last 10k, empty the tank like a TT.

**you need to balance risk. I once accidentally caught and sat with a bunch or riders who then decided to push a pace line on a road section about 40k in, I used this to my advantage by sitting on the back, increasing my pace for 10 minutes therefore yet overtook them all later at the point of d) as I had much more energy left.


Pacing is tricky and something I struggle with even on “practice” rides. It is really easy to go out too hard because you feel good at the start and you are fired up for race day. However hours into the race this can catch up to you. Much better to be able to push hard towards the end. This is tricky though because a lot of races, even long ones, seem to start really fast especially at the front of the pack.

Most people will tell you a negative split where you are faster in the second half is going to produce that fastest overall times. This usually means holding back some during the first half of the event and then winding it up as you work towards the finish. @sryke and @kryton57 both make really good points here.


Holding back for the first climb is really smart, as is keeping it under threshold for the first half of the race and focusing on optimum fuelling however…
My best results and most memorable races have been when I’ve put in a massive dig at the start to get into the very front of the race (if can be a right bun fight if there is going to be singletrack on the first climb) followed by a near max effort on the first climb to make sure you get over with the front group. There will usually then be a bit of a ceasefire for a while as the group of 10-20 riders will have detached from the front of the race. I’ve heard this described as riding the pressure wave and it is like surfing; you’ve got to put in a lot of effort to catch the wave but once you’re up on it, it can be a pretty smooth experience.
I remember one race where my heart rate stayed above threshold for the first 45mins but then the pack eased to conversational pace for a while. It did get tough again later on but I managed to limit my losses for a 3rd place vet, which was pretty decent seeing as the top two places were both multiple national champions and I only conceded 2 mins to them in 80km. I was wasted from halfway through the race but the speed of that group meant I only had to suffer for three hours.


Be sure to look at the course and your skills as well. For example, if you can really flow single track quickly, then at the Mohican, you might want to burn a match to get near the front and miss the stop, stand, and wait for the bunch up at the trailhead. (Been too long, but my memory says passing was very difficult for something like an hour with the long line on trail) Especially if you will be slowed down by others on the trail if you don’t. Others it may not make nearly the difference.


Just did the “Mokka100” on the weekend (my own thing - pretty much rode the course other than detour to and from home). Power meter is about 3 weeks away but followed everyones advice and it worked out sweet. Checked my Training Peaks and I assume it is an estimated IF, but it came back as 0.79 so your advice was pretty much bang on! Cheers


Hi, I am a new member to this forum and I was wondering if I could get some help on a pacing strategy for a race that I have coming up in the near future. This race is a 50 mile marathon mountain bike race that I think I will be able to complete in about 4 hours, with about 3 of these hours on climbs. This 3 hours of climbing is split up between 10 different climbs, and I was wondering how I could properly pace this? None of these climbs push me above threshold, about 300 watts with a W/Kg of 4.3, so I was wondering if I could pace all of these at sweet spot (88%-94% of FTP), does this make sense or is this to ambitious of a goal and high tempo would be a better goal? Thank you so much!

Given my experience of n=0 it sounds like a plan. Earlier in this thread @Jason_Kennedy talked about using the IF to judge it. I’ve had a few dry runs of IF @ 0.79, 0.888 & 0.86 the first was mint with heaps to burn but I think the others were holdable for the distance (maybe just). Maybe have a play with them on some longer rides and see how they work out? I’d be interested to know how you go


I hope the training is going well @AntC. Agreed at somewhere between the 0.8 and 0.85. Did you use a power metre for the second 2? The Whaka100 updated course looks a bit easier than the previous version so i do think 0.85 might be sustainable.

For sure, loads more friendly!!! I think the new start works better, less of a logjam than at the horse track so should be easier to run some smooth power for the first 20mins or so.

Yep, Running power meter for the last two. The 0.888 one was for just under 90km of the old course and the old GI distress was pretty real. Not sure if due to intensity or trying to smash too many carbs in a hurry near the end to catch up. Eased off for the second one which was also shorter (75ish kms) but race pace start and was more manageable- still going to be a big day which ever way you look at it :smiley:

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Hey Ant, do you mind letting me know your (rough) FTP? I’m also trying to sort out pacing and so far 0.8 seems quite high. I’ve not done any trail rides fresh yet but more information is good.

Feel free to PM me if you don’t want to put the numbers out there.

Yes @AntC , that new trail is nice and smooth with a gradual incline although I think there will still be a log jam of sorts as it is a couple of hundred metres from the start and only 2 riders wide so I guess if you don’t want to be held up the start is still key.

I like to keep things simple when I’m racing. For XC races, I like to keep my HR above a certain point to help ensure I’m pushing hard enough. For XC Marathon, I like to keep my HR below a certain point, or at least minimize how much time is spent at that level or higher. It’s not ideal, but it works for me.

Here’s my HR data from an all out single lap effort, an XC race, and a Marathon race.