CX power analysis from 2018, maybe interesting to some

I wrote up a blog post about this but thought I’d make a thread, hopefully fellow CX racers will find it interesting. I was curious to see what kinds of trends I could see in my race data from last year. I won’t bore everyone with details, but in essence, I found I was consistently doing NP of 220w (0.8 IF), I didn’t have anything I’d consider serious 3min, 90sec or 1min efforts, I used the TR workout analysis to find 30sec intervals over 300w, and it seemed like all my 30sec efforts were in the neighborhood of 110%. Weirdly consistent.

So I’m hoping at the very least that my fitness gains over the winter can result in NP of ~250w for races and 30sec efforts of 341w, which are my current equivalents, although I’d prefer to get those 30sec efforts to 125% or higher and I’d really like to get my IF closer to 0.9, just so I don’t feel like I left too much out there.

Anyhow, hopefully this is interesting to some, it’s not anything I’m trying to make into any sort of action plan at the moment, just curious to see where I was.


I wonder if this goal is appropriate for CX? I’m thinking that CX is almost the polar opposite of TT because you spend very little time at functional threshold.

I honestly don’t know, all I know is I was finishing relatively fresh so for me I was feeling like I was leaving some effort on the table

But also it’s about spending more time above threshold that would get the NP and IF up, not that the .9 would be a steady effort

I tend to measure my CX race intensity by comparing my <5min peak power numbers during the race with my PR numbers for the season. That has always matched how I feel after a race. IF saturates quickly as a measurement and just not change very much.

Of course, this whole topic is highly dependent on the type of CX course. :slight_smile:

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indeed, I was surprised that I don’t really have any big 1min-3min numbers, our courses in New England seem to be all about the 30sec efforts (or at least the way I race them, which could be all wrong lol), but I guess I’ll keep training up to 3mins even if I hate anything over 90sec for intervals!

That can depend on the course. But generally speaking, the avg power is low, but there are loads of massive accelerations/sprints (think VO2 max and anaerobic efforts).

I think this is impossible. I looked up a random good race of mine an if had a intensity factor of 0.78. My HR was constant above 90% peaking some beats below HRmax.

Yes, but is see it as Qing and Yang. My passion is in CX and in summer i focus much in TT. In CX I benefit from my aerobic engine a lot., specially on courses with a not so short climb.
And build up the anaerobic capacity after the TT season takes not to much time.

PS: I looked up a good race with a ncie climb an here i have a IF of 0.85. But this maybe the optimal course for a high IF

Not impossible in my case, I have 12 races of data (did a few without my power meter as well) and 9 races had an IF over .8 (in fact looking closer, my average IF was 0.83) and 3 of them under 0.8 (2 of which required more off the bike stuff). But really my main focus are those 30sec efforts, I really should be getting more than 110%, so I’m hoping those are more like 125% (or hopefully higher) this season and just find ways to maximize my effort

Agree with @redlude97. I don’t race with power. I look at HR more. If it’s not pegged for those 50 minutes, then I didn’t go hard enough. Usually around 188 for a race, into the low 200s as well. Also a decent amount of running pending the course, but pretty much everyone in CO cat 3 can bunny hop barriers now. I can’t. Well, I can, but am too nervous to try in a race.

I like to do a lot of 30/30/30s - 30 seconds full gas, 30 seconds coasting, 30 seconds carrying my bike fast.


well, in race i collect the date, but not look a it much during race. But to judge if i spend enough effort I look only at the HR. Power say not so much, specially because our course have also often a amount of running,.

My default workout is 13x30/15 (iso effort) and i do lot a hill sprints 10-40 sec and efforts ranging from 60 seconds to 2 minutes., This are more or less all out efforts with some minutes of recovery.

I did also something similar 10 times 30/30. 30 Sec seconds full gas, 30 easy with mount/dismount, 30 seconds running. and so fort
But i found difficult to controll to right intensity…


Nice. It’s part of a workout Katie Compton was doing a few years back - heck she probably still does these - a friend who was a solid cat 2 showed me this. He could also rally on his cx and was so fast and smooth.

Also, I don’t even look at my Garmin when racing. I have it in my pocket of my skin suit if I have to swap bikes. Gather the HR data after and see when I blew up, when I could have gone harder, or just sat in because I was so far off the back.

So many factors to NP. Mine varied fairly wildly over the season. Course design surely has an impact. Heat and mud reduced my NP, sometimes a lot. And yet mud races for me are great results, but hot races consistently mediocre.

I’m with you, though, on 1-3min intervals simply not appearing in my race output. I was just complaining about that a few days ago on here when someone asked about short power build for cx. Definitely planning to do a few weeks of sprint work leading into cx season this year.

You got me curious about time-at-intensity, but I find it tedious to analyze the data too much. I recently tried which tries to analyze your ride and pick out intervals. Maybe it’s a bias in the algo, but most of the intervals it picks out are short:
Definitely not perfect analysis, but its interesting to see just how often 6 seconds pops up.

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Most of my IF were around 0.8 if it was a fast course. If there was mud or a lot of running, then lower. Just too much coasting or running to go much higher than that. I do get my highest HR numbers from CX racing though. Actually Trek CX when it was 100F, I went over my HR max due to the environmental conditions.

same for me. But i have two courses with a short steep climb at the end of the lab. But also on the other courses the HR is high. I think this due to the intermittent nature of the power output combined with the competition.,
In a ramp test i can’t reach this HR, maybe lack of motivation. To fight at for the placement one to one, works for me better.
I saw only higher HR on trainer with intermittent exercise, but this probably due to heat.