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Data on Planning your Season for best Kona Performance

Before Kona, there was a lot of speculation about Caroline Steffen’s prep which included a full Ironman-distance race just six weeks before Kona. Now that the race is over, I have a closer look at some of the data on the impact of season planning for performance in Kona.

Of course this analysis has some limitations:

  • There are not too many data points – after all, we only had 85 pro athletes on the start line in Kona.
  • Each athlete recovers at a different rate, the analysis can only be a general guideline that has to be adapted for each athlete.
  • My data and analysis is limited to the Pros, the picture could be different for age groupers.

With these caveats out of the way, let’s have a look at the data. I’ll be showing graphs of athletes Kona performance. The Kona performance is the time difference (in minutes) between their Rating (based on all their previous results) and their normalized Kona finish time, after accounting for the course and conditions on race day. A „normal“ day would produce a Kona performance of 0, performances larger than 0 mean that the athlete performed better than expected, negative numbers indicate that things didn’t go quite as well.

Last IM before Kona

The first graph show the athletes Kona performance in relation to the time that each athlete took between racing his/her last Ironman-distance race before Kona:


The month names indicate when the last IM-distance race was, the light blue line shows the median Kona performances, and the thicker blue line a „best fit“ for the data.

Here’s the raw data behind this graph:

Month Athletes DNFs DNF % Median Performance
November 5 1 20% 3:12 (not shown)
March 8 2 25% 2:20
April 1 0 0 (not shown)
May 6 0 0 9:42
June 13 4 31% 1:52
July 26 6 23% -1:52
August 22 5 23% -2:39
September 4 0 0 -12:00

There are a few interesting observations in this data:

  • The time since the last IM does not seem to have a discernible influence on the DNF rate.
  • In order to deliver the best Kona performance, there seems to be a sweet-spot in May. (But if we included the November data, we would end up with a relatively „flat“ graph before May. Hard to tell if there is much of a difference with so few data points.)
  • After May, the less time there is before Kona, the more likely it is to have a bad result. The 2013 data doesn’t show much of a difference between July and August.
I’ve posted a similar analysis in 2011, with very similar observations.

Number of IMs before Kona

There is another way to look at the Kona performance: in relation to the number of IMs athletes have raced before Kona:


Again, the light line with the data points show the actual data, and the darker line a best fit. (6 is actually a category representing 6 or more races. It won’t be a surprise that the athlete with the most was Peter Vabrousek with 11 IM-distance races between Kona 2012 and 2013.)

Again, the main information is relatively obvious:

  • The more IM races you race, the more you’ll probably struggle in Kona.
  • The ideal number of long distance races (outside of Kona) seems to be either one or two.


I think that there are a few implications for athletes that want to focus on their Kona performance:

  • Avoid long-distance races close to Kona. (It’s just one data point, but I would think that Caroline is wondering what would have happened if she didn’t race MetaMan.)
  • Try to qualify at the end of July if possible. (The best case scenario is probably Jordan’s 2012 season: Qualify late, then have a conservative Kona race to get some good points for the next season.)
  • Make a decision whether to focus on Kona or one of the European and North American championships (Frankfurt in July, Mont Tremblant in August). As far as I know, with the exception of Chrissie Wellington we’ve never had the same athlete win both in Frankfurt and Kona.
  • If you have enough points, just race an Ironman either in November („just validate strategy“) or in April/May, then have a focused Kona build. (This seems to be the strategy that Rinny feels very comfortable with.)

Unfortunately, this is a bit in conflict with the way WTC has set up the KPR system – late season big races, and the hectic August qualifying. In my opinion, this is not the best way to set up athletes for great Kona performances.

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