Post-Race Analysis – A Detailed Look at Ironman Austria Bike Performance

The European Ironman season is at its peak, Sunday’s are spent on my laptop tracking triathletes. Having athletes in Ironman Austria and Challenge Roth has ensured a busy fortnight; when the race is over the analysis begins. Debriefings are a pleasure if the day went to plan, but when goals were missed it is a challenging and much more important process. I push my athletes for details, data, any information that will help me understand what happened. Answers aren’t always easy.

I had three athletes at Austria looking to break through the ten hour Ironman barrier. They regularly trained together; they were fit, hard working and good swimmers. The final month before tapering had inconsistencies, work and light bouts of illness interrupting training, but feedback said ten hours was a reasonable goal. On the day two comfortable beat their targets, the third suffered and fell short of our intentions. What led one to disappointment where his training partners succeeded?

All three started the marathon with the potential to go under ten hours, but one was unable to race as he trained. Their performance was a product of the proceeding six hours, events on the bike had determined their ability to run. The bike was the obvious area to focus on.

The Athlete Data

When it comes to analysing results the more data to consider the better; I want to relate details of performance to perceptions of effort. Many of my athletes train and race with power meters, the three in Austria were no exception. Once I received their reports and power data I set about analysing the race.

Athlete A Athlete B Athlete C Russ (IMNZ 2010)
Ironman Austria 2011 - Athlete A Bike Performance Ironman Austria 2011 - Athlete B Bike Performance Ironman Austria 2011 - Athlete C Bike Performance Ironman New Zealand 2010 - Russ Cox Power Data
Ironman Austria 2011 - Athlete A Power and Heart Rate Data Ironman Austria 2011 - Athlete B Power and Heart Rate Data Ironman Austria 2011 - Athlete C Power and Heart Rate Data Ironman New Zealand 2010 - Russ Cox Power and Heart Rate Data

Despite the range of results their power data appeared similar, all three contained elements that might indicate pacing errors. Many factors play into Ironman performance so whilst I wasn’t surprised by similarities, I questioned why one athlete had struggled more.

  • Power falls over the course of the race from an initial level trending above 75% FTP to below 70% of FTP. Their recommended power cap would have been at the 75% FTP mark.
  • There are numerous spikes in power throughout the race, particularly in the first lap; these often cross FTP for short durations.
  • Initial heart rates are high, expected after the swim and transition, but they remain high for an extended period. Athlete A had the most success settling his heart rate (and similarly controlling early power)

I plotted my data from Ironman New Zealand 2010 for comparison. A good race though I felt I may have pushed the bike too hard, something reflected by the high percentage of FTP I held. However the overall trend was within my target power range and rose while heart rate remained stable. I ran reasonably strongly and finished well off the back of this ride. Not textbook racing, but the result had been good.

My overall impression was all three went out too hard and surged a little too much, with notable consequences in one case. Side by side it was difficult to pick which performance had resulted in the harder day; I didn’t have a solid grasp on what happened. I decided to consider the distribution of power in proportion to FTP – how much time had been spent working too hard?

Comparison of Ironman Power Distribution for CoachCox athletes at Ironman Austria 2011

How hard I worked on the bike in New Zealand stands out; I believe the FTP values are correct, increasing mine would not overly impact the chart. But the main point was to consider my three athletes.

  • Athlete A – was evenly distributed around a central 75% peak, but power tails off slowly as he crosses FTP. There is definitely a benefit in controlling surges more.
  • Athlete B – demonstrated a faster tail off in effort and less work above FTP; he also spent more time coasting. His distribution of power is quite broad and he could gain from working more consistently in that central band
  • Athlete C – spent a lot of time at lower percentages of his FTP (below 70%), but also worked a lot above FTP. His histogram is very broadly distributed and he needs to control his surges early in the race to avoid fading.

Other Factors

Although I’ve concentrated on power and heart rate I am well aware many other factors come into play. Performance in the water has implications for the rest of the race, but with all three being strong swimmers I felt its affect would be minimal. I have a stronger suspicion that nutrition played a heavy role, the two who broke ten hours are clearest on how much and how often they consumed calories. Greater awareness of fuelling potentially indicating greater overall management of race performance.

Pacing is clearly a challenge for relatively inexperienced long course athletes, especially those with ambitious goals. Mistakes are easy even with power and the results play out over the entire race. A conservative approach can insure a comfortable finish, but may not deliver the desired performance; on the other hand greater aggression is risky. Practice allows an appreciation of the feel of Ironman pacing – how easily it starts and how hard it finishes. It takes time to develop a finer sense of where the line is between optimal pacing and meltdown.

Lessons for Ironman Pacing

Studying this data closely has given me a lot to consider regarding race pacing. My guidelines to athletes need to be clearer and further emphasise the importance of nutrition and pacing. The rules aren’t strict and there’s room to support and athlete’s strengths; testing individualised strategies for more advanced triathletes would be the optimal approach.

  • The start of the bike should feel easy. Heart rate may be high, but not power and effort.
  • The elevated heart rate should be lowered as soon as possible, stabilising at a level comfortably below threshold. Heart rate and feel should not be ignored even when using power.
  • Nutrition is vital! Know what you’re consuming; you should be able to accurately recount it after the race.
  • It is possible to push the bike harder than a 75% effort, but it is dependent on training and fitness in both bike and run. Test this in training.
  • Spikes in power are never a good idea and minimising time over 90-95% of FTP should be a basic aim.
  • Power distribution should focus on a narrow band of sustainable intensity.
  • A proportion of long rides should attempt to simulate racing to develop a pacing strategy.

The Results

On the day Athlete B was first to finish, pairing a fast bike split with a superb run. Athlete A followed, demonstrating a consistent performance. After fading on the bike Athlete C suffered through the run; he pushed on and made it across the line, all be it later than hoped. All three can learn from the experience and build on it in future races.

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  • jaime

    Riding in a peloton makes the power to drop (and to coast) , and we know that drafting is a huge issue in Austria. Not to say that that was the case but you should at least consider it.

  • Jaime,

    This is true.

    I’m going to have to take my athlete’s word that they didn’t draft on this one. I’ve no reason to doubt them.

    What would be interesting is to compare a file from a drafter with data from those who avoided the packs. I’d happily preserve anonymity if someone provided me with the power data from drafting the race! Being able to put some figures on effort levels and energy expenditure would be nice.


  • Brett

    Hey Russ, love the analysis. I was curious how you were producing those plots. Do you do that inside WKO, or outside? I use WKO myself, but would have to say I am not that literate in it yet. Can do the simple to moderate stuff, but haven’t been producing the fancy charts you do. I like the trend charts, as I really want to make sure I am neg splitting my long rides. Good luck at the Outlaw.

  • Hey Brett,

    Glad you liked the analysis, hoping to have some Roth data to look at in the next week. Mix of results again, going to be interesting seeing how they compare.

    The charts I produce are done using Excel 2011 for Mac. Generally I import the data into WKO+ for my initial examination, it’s the main tool for analysis. Then I export the data into Powertap CSV format as it’s the easiest to work with in Excel. I’ve put together an analysis spreadsheet to automate the process of generating some of these graphs and to pull out some analysis on pacing numbers. Takes me a few minutes to generate the graphs and numbers now. I’ve a few ideas to expand the analysis and allow for more complex pacing strategies to be compared.

    Hopefully the Outlaw will give me a good bike file to analyse if nothing else! I’m not sure how I feel about the run at this point, it could be a long day once I’m off the bike.


  • Brett

    Thanks for that Russ, it was very useful. Just took my Ironman Australia file out of WKO and had a look using the trend line analysis. Can definitely see how the power level consistently dropped overtime, as did HR, but not quite as pronounced as the power. This was definitely a lack of swim fitness catching up with me, as well as taking the rollers way too hard in first 2 hours of race. Love lots of the analysis you pull out, certainly very useful.

    How are you finding the swimsense monitor? I am thinking of investing in one.

  • Hey,

    If you send me the WKO file I’ll run it through my spreadsheet if you like. Pull out a few more details for you. Always interested in seeing race power files, you can learn a lot from them.

    I have to be honest and admit I’m not swimming enough! But the Swimsense is a powerful tool. Have a look at the my last, abysmal, swim (Swimsense Data) for an idea of the stats you get. This data can go straight in Training Peaks and also be exported into a spreadsheet. Really see how you swim and get some idea of stroke rates and DpS. Once the Outlaw is out the way my intention is to get myself in the pool and start using this as part of a focussed program to get me back up to speed.


  • Thomas Peoples

    What was the consensus on the average bike course distance?

  • All three files came in around the 175-176km mark, so 4-5km short by three independent GPS measures. I have heard of others which didn’t measure it quite as short, but never of any measuring it on distance or long.