Predicting the best of the best: Kona edition!

The top long-distance triathletes in the world have descended upon Kona, Hawaii and are gearing up for perhaps the most meaningful race of their lives on Saturday: The 2018 Ironman World Championship. The rest of us are getting swept up in the energy from afar and are secretly, or maybe outwardly, making our picks for the podium.

Triathlon performance is difficult to predict. There are three sports, over 2000 athletes, tons of gear, and, well, Mother Nature. When the number of variables increases, predictability decreases. It’s basic math.

But, complex mathematics is a different story. Some studies have successfully implemented statistical models to predict triathlon performance using internal and external factors. One study developed a model using anthropometric (e.g. shoulder and pelvis width) and physiological (e.g. VO2max and blood lactate) parameters, and predicted Olympic distance race time in elite male triathletes (Hoffmann et al., 2017).

Beyond physical attributes, experience plays a role in triathlete performance. There’s a lot of trial-and-error in triathlon, especially in regards to nutrition, so it reasons that people who have multiple races under their belt, also have a better sense of what they need for a solid performance. One study (Knechtle et al., 2015) supported this notion, showing that half-Ironman performance was predicted by previous triathlon experience. In another study (Gilinsky et al., 2014), significant factors were personal best half-Ironman race times, faster goal times, and belief in the importance of achieving that goal time. Considering the uniqueness of Kona, it could be hypothesized that Kona experience, in particular, influences World Championship race performance. Kona is a beast of a location for this race. You might have to deal with headwinds both ways on the infamous Queen K highway and it’s difficult to replicate the heat and humidity while training anywhere else - not to mention performing on a world stage.

So, what about the space between the ears? What about those intangible qualities that separate the excellent athletes from the otherworldly ones? When you’re looking at the best of the best, physical factors are nearly indistinguishable. It’s the mindset they exhibit on a particular day that matters - and the science is beginning to explore this. A 2009 study (Stoeber et al.) showed that seasonal best swimming, biking and running times predicted half-Ironman performance to a degree. The statistical model was enhanced when measures of perfectionism and motivation were added. Specifically, those who scored higher on perfectionism had faster race times. Additionally, performance-approach goals (e.g. the desire to do better than others) predicted positive race performance, but performance-avoidance goals (e.g. the desire to not do worse than others) predicted worse results. Sure, triathletes say they’re motivated by intrinsic properties like beating their personal best. But, it seems they’re quite competitive and absolutely care about performing better than others. Shocking.
The fun thing about predictions is that they can go out the window in a breath. Without applying any statistical models, here are my predictions for the 2018 Ironman World Championship. Maybe it be a race day for the books!


1st - Daniela Ryf

2nd - Rinny Carfrae

3rd - Sarah True


1st - Javier Gomez

2nd - Patrick Lange

3rd - Andy Potts


Gilinsky, N., Hawkins, K.R., Tokar, T.N., and Cooper, J.A. (2014). Predictive variables for half-Ironman triathlon performance. J Sci Med Sport, 17(3): 300-305.

Hoffman, M., Moeller, T., Seidel, I., and Stein, T. (2017). Predicting elite triathlon performance: A comparison of multiple regressions and artificial neural networks. International Journal of Computer Science in Sport, 16(2): 101-116.

Knechtle, B., Knechtle, R., Stiefel, M., Zingg, M.A., Rosemann, T., & Rüst, C.A. (2015). Variables that influence Ironman triathlon performance – what changed in the last 35 years? Open Access Journal of Sports Medicine, 6: 277–290.

Stoeber, J., Uphill, M. A., & Hotham, S. (2009). Predicting race performance in triathlon: The role of perfectionism, achievement goals, and personal goal setting. Journal of Sport & Exercise Psychology, 31(2), 211-245.