Anaerobic Work Capacity (AWR aka W') vs Repeatability (FRC)

I’m over here working on my cyclocross limiters and find that having the ability to go deep repeatedly is likely what’s holding me back. I can ride a solid tempo throughout a race, but my matchbook isn’t as big as some of the other guys’. I’m trying to get more info on what types of workouts can help with this and I’m confused between building more capacity versus more repeatability.

In other words, it seems like to build more W’ capacity you need to go hard, and fully recover, before doing your next interval, whereas in order to build repeatability you want as little rest in between intervals (40/20, 30/30, 30/15 type stuff).

I don’t see this get discussed much here, but I think it’s a crucial element to being a successful bike racer. What workouts have you found success in doing? How do you like to structure these into your week?


AWC aka FRC aka HIE aka W’ has always, always been my limiter (as a swimmer decades ago, my best 100 free was a just little faster than my 100 splits in the 500…ugh…).

My 1 minute power this year has been…wait for it…a whopping 515w. 5 minute is 415. The last 35 years have taught me that working on durations under 3min doesn’t yield a lot of gains in max power, but what I can do is develop repeatability and over/under tolerance.

Workout 1: :30 all out, 2:00 recovery. Do those for a 30-40 min block. Hardest consistent power you can hold (these usually end up being at my 1 min power or slightly higher).

Workout 2: :30 all out, 4:30 recovery. Try to get max :30 power on each one.

My favorite is to follow a 4 x 4 VOs interval workout with #1.

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I don’t believe that what you’re describing is necessarily best dealt with by a major focus on anaerobic capacity.

As the articles say, you start to drain the anaerobic battery when you go over FTP / CP. So a very good way to avoid this is having a higher FTP so you don’t go over it so much.

That’s not to say that anaerobic or sprint workouts don’t have their place - but IMO they should be used judiciously and sparingly, even for cyclocross, as they require a lot of recovery and can easily leave you burned out if overdone.

I agree with the prescription from @stevemz for a vo2 block, followed by a few anaerobic sessions, but equally important is scheduling at least a week to recover from this and adapt before your first (important) race.


Cheers. Yes, raising FTP is always nice, but I think given where I’m at in the season raising it won’t be possible, simply maintaining will be the goal. FWIW, I’m at my all-time high FTP of 325 coming into this season. Last year I was 5-10w less at this point. I think more realistic gains could be had in the AWC or repeatability department.

The first race is this Saturday, but I’ve been building up with some race-simulation as well as work that is targeting VO2max and Anaerobic systems with some LT work sprinkled in. Here’s a peek at the last 8 weeks or so. I feel like this is decent prep, not as structured as I had hoped, but I think just the right amount work to rest given the season is just starting this week. Much appreciated if you look at these rides, although not necessary.

Sep 7
45 min CX race
Sep 4
45 min CX race
Sep 1
August 28
45 min CX race
August 22
CX race simulation + sprint starts (90 min ride, 30 min work)
August 20
1x40min @ high SS/LT
August 18
CX race simulation (90 min ride, 30 min work)
August 14
Tabatas (15x 20s on/10s off) 2x
August 12
60min CX Race
August 8
Over/Unders + 4x4min
August 6
30/30s (2x12)
July 30
2x 5x1min Power Intervals (= work to rest)

The remainder of the month is race-free an will be devoted to training so that I’m in a better spot come October and into November. Here’s what I have planned:

Tonight: 45 min race
Saturday: 45 min B-priority race

The following 4 weeks look like this. I’m focusing on VO2max work (Megantic and Richardson +1) as I don’t have races scheduled these weeks, but then I shift over to AWC workouts in weeks 3 and 4. I’m leaving the weekends open for TBD workouts/CX skills rides.

Thoughts? I’ve never trained the AWC/W’ side of things so I’m open to hearing feedback and other thoughts. I do think this is my limiter though.

Current weight: 81-83kg (fluctuates)
FTP: 325w (tested last Friday)
Realistice FTP: 310-315
CX Category: 3/4

W prime is a relatively new concept to me, but I’m quite intrigued by it. From my (elementary) understanding, a couple of all out tests in the 1-8 minute range are required to estimate W’. This is probably a silly question, but is there any way to derive an estimate from a MAP test like the Ramp Test?

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Not from one data point. It could be implemented by TR on their power curve, but that is a larger discussion.

W’/FRC is useful as an absolute value to track alongside FTP, but the recharge rate hasn’t been solved yet, so there is varying usefulness beyond just estimating the size of the glycogen battery.

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W’ is the tank, Monod and Scherrer back in 1965 with the concept of critial power. W’ balance is the model of how it empties and refill, Skiba et al 2012.

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That 3-min all out test sounds brutal. :face_vomiting:

from what I understand (blogspot link above, and other places) is that one way to think of it is that raising AWC/W’ requires raising your power duration curve for efforts less than say 5 or 10 minutes. That implies if you’ve nailed repeatability, then start working on increasing power of vo2/anaerobic repeats. In other words, instead of doing intervals at 150%, raise it to 160% or higher. Its less about longer intervals, and more about increasing power.

Somebody correct me if I’m wrong.

This is what I have garnered. Full gas efforts to exhaustion (likely less than 1 min) and then tons of recovery between intervals. The goal seems to be that you need to completely deplete W’, let it recharge fully (6-12 min depending on athlete) and go again. PEZ has some articles on this as does Tailwind Coaching.

that is my understanding as well. And anecdotally, looking at my own data in Xert/WKO, my largest AWC/FRC came after a month or two of repeatedly going full gas on a couple of one minute Strava segments (I could have done a better job at structuring, but unintentionally those efforts built up AWC).

@anthonylane @bbarrera the latest WKO webinar is a good one for the capacity side:

(FRC section starts at 42 minute in)

The repeatability side is a little bit more complicated to get into.

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thanks, hard to get the story from skimming the slides. Look forward to giving it a listen!

If I’m fit and can handle the workload, on a Wed after a session of longer duration on Tuesday.

Might need and endurance day in between though, and could shift this to Thurs if not racing an A Priority Race on the weekend.


If we are to believe that study, my w’ as modelled by is about max i could expect at 24 kJ. However i still feel like going over threshold is still a weakness for me. If i could get an if of .9 for an off-road race effort of about an hour I am quite happy. I was wondering if it was because my anaerobic system wasn’t developed enough but it seems more like it is my aerobic system cant recharge it quick enough.

Based on that article, if most people have a similarly limited w’, that bigger variable between them will be their vo2max. More and more it seems like moving that vo2 metric up throughout the year should be our main focus, and sharpen specificty just prior to race season.

I had Megantic scheduled for this morning.

Got a late start and opted for the 45-min (-1) version that has 3 sets instead of 4. Great choice. This is such a hard workout. Especially at 5:45 am.

That initial surge to 150% FTP for 30 seconds really hits things off and establishes a high heart rate, and then the 15/15 (125%/88%) over-under sections are brutal. Zero recovery found at 88%. I found it impossible to hit the 125% surges and generally hit around 110-115% of FTP.

I think that it was still a very successful workout though and clearly addresses my limiter in repeatability.