title: What predicts performance in ultra-triathlon races? - a comparison between Ironman distance triathlon and ultra-triathlon.
abstract: OBJECTIVE
  This narrative review summarizes recent intentions to find potential predictor variables for ultra-triathlon race performance (ie, triathlon races longer than the Ironman distance covering 3.8 km swimming, 180 km cycling, and 42.195 km running). Results from studies on ultra-triathletes were compared to results on studies on Ironman triathletes.
  
  
  METHODS
  A literature search was performed in PubMed using the terms "ultra", "triathlon", and "performance" for the aspects of "ultra-triathlon", and "Ironman", "triathlon", and "performance" for the aspects of "Ironman triathlon". All resulting papers were searched for related citations. Results for ultra-triathlons were compared to results for Ironman-distance triathlons to find potential differences.
  
  
  RESULTS
  Athletes competing in Ironman and ultra-triathlon differed in anthropometric and training characteristics, where both Ironmen and ultra-triathletes profited from low body fat, but ultra-triathletes relied more on training volume, whereas speed during training was related to Ironman race time. The most important predictive variables for a fast race time in an ultra-triathlon from Double Iron (ie, 7.6 km swimming, 360 km cycling, and 84.4 km running) and longer were male sex, low body fat, age of 35-40 years, extensive previous experience, a fast time in cycling and running but not in swimming, and origins in Central Europe.
  
  
  CONCLUSIONS
  Any athlete intending to compete in an ultra-triathlon should be aware that low body fat and high training volumes are highly predictive for overall race time. Little is known about the physiological characteristics of these athletes and about female ultra-triathletes. Future studies need to investigate anthropometric and training characteristics of female ultra-triathletes and what motivates women to compete in these races. Future studies need to correlate physiological characteristics such as maximum oxygen uptake (VO2max) with ultra-triathlon race performance in order to investigate whether these characteristics are also predictive for ultra-triathlon race performance.
authors.affiliation: Institute of Primary Care, University of Zurich, Zurich, Switzerland ; Gesundheitszentrum St Gallen, St Gallen, Switzerland.
authors.forename: Beat
authors.initials: B
authors.lastname: Knechtle
authors.affiliation: Institute of Primary Care, University of Zurich, Zurich, Switzerland.
authors.forename: Matthias Alexander
authors.initials: MA
authors.lastname: Zingg
authors.affiliation: Institute of Primary Care, University of Zurich, Zurich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rosemann
authors.affiliation: Institute of Primary Care, University of Zurich, Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Stiefel
authors.affiliation: Institute of Primary Care, University of Zurich, Zurich, Switzerland.
authors.forename: Christoph Alexander
authors.initials: CA
authors.lastname: Rüst
keywords: age; cycling; experience; running; swimming; ultra-endurance