Dissecting A Cyclocross Race

I posted a simple question on Twitter over the weekend: Would people be interested in a post about the breakdown of a CX race – looking at it from a power and fuelling perspective? The answer was a resounding yes, which was nice. Now that I have a break in thesis writing I can get to it. You may want to put the kettle on first, it’s a long post and didn’t go quite the way I expected. But first…

The reason behind the question came from a coaching session on Saturday morning where I was discussing the upcoming national championships in Dundalk. After looking at the course I spotted 35 corners at best guess from the image I was handed, many of them dead turns. Straight away I wanted to know surface, pitch of the course, hills. I was stripping the course down to the basics of what needed to be done to train for the course specifically. Micro then macro. Work from the course to build the training structure.

Not being blessed with the most amazing bike handling skills or natural fitness it is the method that allows me to prepare for specific races and pull out moderate results. I used this for the 2011 cyclocross championships in Lurgan. It’s a method of thinking that allows me to remove any emotion from preparation for a race, remove the things I cannot control, take control of those I can. It is a coping strategy.

Overview CX Nats. 2011:

The race did not turn out as I had planned or hoped, few do. Lurgan is a course with sodden ground, short sharp run ups and flat out sections with few turns. It was going to be a day for working at and above threshold with few major power spikes outside the first lap. On the day it froze solid, I hit the deck with a bunch in the first 500m and spent the next two laps chasing back into a bunch contesting 10th – 15th. Race plan went out the window. However, I rode the race with a power meter for the whole thing as I never had to pit out the bike. Thus a nice data file came out of it (At the bottom of the post if you want to download it and laugh). If I recall I weighed 76kg at the time of the race. As it was not that hilly a race I don’t think power to weight was that important for it.

CX Zone Breakdown

Outright interesting the amount of time spent in Z1 ‘Active Recovery’ with power less than 145W being produced. For CX this should just read ‘Running or coasting’. This will vary course to course, with Dundalk I’d suspect this will be quite high for many riders. The counter side to this is Z7 ‘Neuromuscular’ with 20% of my time pushing out supramaximal efforts and over 50% of the race above threshold power. The normalised power (taking out the rolling zero power bouts) comes in just above my threshold at that time. So eradicating the rolling time, I was racing at my limit for the whole race…but we knew that anyway.

This simple break down shows that cross is a game of on and off. On at maximal capacity, off trying to recover from it. The trick is thinking about where you are recovering. Usually, it is on the most technical sections of the course, either descending or taking corners while coasting. Yet…most people never train their technical ability when going at their hardest. They perform their hard efforts on the turbo or road and assume that it will transfer to the course. A tri-athlete mentality that fails to hit the specific needs of cyclocross. Why do people do that?


A simple MTFU principal rarely works in coaching. Most people shy away from it, those who tend to react well to it make initial gains very fast, then they tend to just turn the dial to eleven and try to sustain it. That way over-training doth lie. However, specific hurt in the right manner will provide a better benefit than just rambling along riding your bike. For Lurgan I knew that the fast straights lead to fast boards that needed to be taken as fast as possible and might be on frozen ground; so I set up some boards on tarmac and practised riding at them fast, dismounting, crashing, then getting up and going again until I could do it. On the day it froze solid and I fell only once, in warm-up trying to bunny hop them. Similarly for St Annes I knew the course as the designer so worked every corner that I was not good on. In the rain, in the dark, on my own, at full gas. When you work in the suck, racing in the suck is easy. Take the course, break it down, train the bits you initially shy away from, train for them at your physical limit so on the day the movement comes naturally.

Fuelling CX:

But how does any of this affect what we eat prior to, and during, the race? Being lucky to have an entire human performance laboratory in my office for the past 4 years has had its advantages. First off fuel consumption rates can be calculated for a subject prior to a race by doing a maximal test, working out how much carbohydrate and fat is burned at different intensities, etc etc…..or… we could just look at the energy expended when measured with a direct measure  the power meter. 792kJ were spent during the race. That is nearly 2 rhubarb and custard Torq gels. It’s not actually that much, yet many of us spend hours before the race cramming in food trying to make sure we have enough to get through it. Simply put: You have enough glycogen in your blood stream and muscle to get you through a cross race. If you are fading, it is doubtful it is fuelling, its called being under trained.

The initial sprint from the start will drain your PCR system, the first lap will drain your available blood glycogen, the next 50mins will be coming from your muscular stores. To increase these we train, more training results in more mitochondria, more ability to use the fuel. Bonking at the end of a cross race is generally down to an underdeveloped muscular storage capacity. Taking a gel in after your warm up laps to top up the tank is fine. However, that gel you take in mid way probably won’t help much unless it has a stimulant such as caffeine in it. The reason comes down to the intensity you are working at and the bodies ability to consume and process carbohydrate. Back again to training at the racing intensity in order to allow the body to process for its current demands.


All races have a start, middle and end. In CX with multiple laps on a deteriorating course, these should be considered as occurring each lap. Each lap has a section where you can start to apply power and attack, a middle where you can hold on/off to those around you, and a section that will end you. Your weakness. Defining these periods before the race, either on a reccy ride, or warming up on the course, is the most important thing you can do.

23 bursts over 600W on the first lap. Graph shown at 5 second smoothing.

Lurgan had its point for me, the fast straights where I could not put out enough power to attack or defend. I had to ride aggressively to make sure I made these sections on the front and force people to come around me on the worst lines. How could I have improved on this; I could have worked more on my 1-2min power output so that I could cope with these sections. As it turned out I rode well technically, I just was not capable of bridging the gap between my group and the next until the final laps of the race where it was too late and I did not have enough in the tank to make many places.

6 periods above 600W for the last lap. Again 5 second smoothing applied.

St. Annes nationals course (2009/2012) had two points per lap that required 1,200W efforts on my part just to keep with a bunch, if you look at the course it is fairly obvious where these are. For many in Dundalk this year, the dead turns will crucify them. 1,000+ Watt efforts will  be required repeatedly throughout the race to accelerate out hard. Many of the turns in Dundalk come back to back and may not allow you to carry speed (That depends on Myles the race director) so are going to smash a stupid rider very early on. In Bradford the obvious section is ‘the descent’, but what about the longer off camber banking before the steps? Or the flat super fast section on the top? Breaking the race down before you get there, working on that which is your ending is more important than new brakes, new wheels or new treads.


Cross is hard. You can think about it all you like but you have to put in the work. If you don’t you won’t go anywhere. However, thinking about where you need to work in a course specific manner can bring rewards. Not possible for every race, but for those that matter, it pays to get it done.


(Left click or ‘save as’) TCX file & PWX file power data from 2011 CX Nationals in Lurgan; Icy conditions, HR data estimated, 9th, 76kg, FTP 265W, running Dugast Rhinos at ~32psi.

Previously posted on Gregs personal blog in Nov 2012

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