Friday, January 3, 2014

Kona Bike Stats

A common topic of debate is how much faster modern triathletes are today thanks to fancier bike equipment. Some claim that legends like Mark Allen and Dave Scott rode their round tube frames just as fast as today's pros ride their high-tech carbon, aero equipment. Comparing bike performance is a tricky business, as a host of factors make bike times very "noisy." The winds at Kona vary greatly, which can affect bike times by as much as 15 minutes or more. Tactics also affect times, as some years the contenders will all be together on the bike course with nobody pushing the pace. To try to answer the question and make sense of it all we have put together some interactive charts.

The slowtwitch kona archive provides a handy source of data on the top 10 finishers each year since the start of Kona. We chose to look at the time period from 1988 to 2013, as this represents a period when the depth of talent was solid, and the course was relatively constant. It also represents a time after the introduction of the aerobar, when professionals were already adopting bike positions similar to modern athletes. Some small course changes have occurred over these years, but the bulk of the bike course has remained the same. First up, we take a look at the average bike splits among the top 10 overall finishers. Hover over a year for more info, pictures, and links when available.
You can see that there is a clear downward trend in bike times. The linear trend shown in light blue suggests that bike times have improved by 13 minutes, or 4.5% over the time period. However, that isn't necessarily all a result of improved bike gear. Records have been dropping in all sports, even those like running, in which equipment plays almost no role. Since running isn't impacted much by technical advancement, it gives us a great point of comparison. We can compare the trends in the Kona run and bike and see if one has been improving at a faster rate than the other.

If the fitness and talent had been the only thing improving Kona performances, we should actually expect to see cycling improve at a slower rate than running, as the nature of aerodynamic resistance limits how much time is saved by a more powerful athlete. But we actually see that cycling is improving about 1% faster than running at Kona over the time period.

Another way to slice the data is to look at the fastest bike split each year. In this case we took the fastest bike split each year among the top 10 finishers. Anyone setting a fast time and then blowing up on the run is thus excluded. Hover over a point below to see who set the fast time that year.
Again we see a clear downward trend in bike times, almost the same trend as in the top 10 analysis in fact. One interesting property of both the top bike splits and the average bike splits is the consistently slow times between 1997 and 2005. Wind, tactics, drugs, and talent are possible explanations that come to mind, but we really don't know. If you have any ideas, drop us a comment and let us know.

1 comment:

  1. Although this is interesting stuff it doesn't really speak to the question of aero bikes being faster and if so by how much. Kona is not only tactical but has primes, and the course changes though minor - adding ten miles to the town section before the wind hits has a huge impact on what riding tactic will carry you to the wind shift.

    Moving the pro start time up lowered the temperature a lot, AND changed the force of the wind for a decent stretch of the bike.

    When I look at the times I remember Wolfgang Dietrich trying to win the bike and swim primes in the early 1990's. Great runners like Mark Allen required a more aggressive bike leg to try and take the heat out of his legs, and to position better for someone who was going to run like the devil later. So single player strategies can shift the lead group numbers a lot. Everyone sat around and waited for the run for several years. Cyclists like Jurgen Zack training with cycling teams like Motorola made a difference - earlier triathletes were not doing stuff like that.

    Tough problem to tackle. Maybe doing the same with a more standard course with more standard tactics - like Rott - would be more revealing.

    Cory Foulk