Ironman boulder is my first race analysis from a busy weekend of Ironman racing. This was the fifth year for the mid-sized US race which comes with the standard 40 age group Kona slots. Boulder is a race that normally draws a competitive front of pack, but is also a challenge for those unprepared for racing at altitude. There is a broad spread from fastest age groupers to the median.
That broad spread is on display when we look at the split distributions. This year’s race is similar, if not a little faster at the fifth percentile, when compared with the previous four year. The front of the pack perform like normal. Median splits at this level tend to come out a little slower than the amalgamated data though.
Prior to 2016 the data mixed DNS and DNF numbers, but more recent years have allowed me to distinguish the two cleanly. DNF rates at Boulder are towards the high end for an Ironman. Almost 10% of those who started the marathon, didn’t complete it. this pushes Boulder up towards a 20% DNF rate at this years race, higher than either of the previous 2 years.
As seen in the distributions, the median splits at this year’s race – at least on bike and run – tend to be slower than the four previous years. From a whole race or whole age group perspective, this was a slower year.
As with most races the majority of competitors are from the host country with a mix coming from around the world. The US takes the majority of the slots on offer although not in proportion with their numbers.
Tracking age group times for specific places over the five years of racing in Boulder shows that at the front of the pack times tend to be close to or even faster than previous year. As we move further back in the field though we see this trend drop off. That said, the times aren’t too different from last year and the reduction in pace at places further back may also be a reflection in the reduction in overall field size.
Based on the slots available to the race and the start numbers I’ve estimated the Kona slot allocation above. From that I’ve calculated automatic qualifying times for each age group. Exact numbers may have varied and roll down would affect qualifying times too. You can compare with other races on my Kona qualification page.
There’s a lot of variation between the age groups when we look at the top twenty results. No solid trend that crosses these divisions as a whole. This year seems most similar to the last year and varies around the average times quite a lot. Still a competitive race at the front, much as it’s always been, but a little slower as we head back in the field.
You can access a spreadsheet of the full results from Ironman Boulder 2018 on my Google Drive.
A growing collection of results and statistics for the whole Ironman race calendar.
Find out what it takes to place in your age group or to qualify for the Ironman Worlds Championships in Kona.