title: Participation and Performance Trends in Triple Iron Ultra-triathlon - a Cross-sectional and Longitudinal Data Analysis.
abstract: OBJECTIVE
  The aims of the present study were to investigate (i) the changes in participation and performance and (ii) the gender difference in Triple Iron ultra-triathlon (11.4 km swimming, 540 km cycling and 126.6 km running) across years from 1988 to 2011.
  
  
  METHODS
  For the cross-sectional data analysis, the association between with overall race times and split times was investigated using simple linear regression analyses and analysis of variance. For the longitudinal data analysis, the changes in race times for the five men and women with the highest number of participations were analysed using simple linear regression analyses.
  
  
  RESULTS
  During the studied period, the number of finishers were 824 (71.4%) for men and 80 (78.4%) for women. Participation increased for men (r(2)=0.27, P<0.01) while it remained stable for women (8%). Total race times were 2,146 ± 127.3 min for men and 2,615 ± 327.2 min for women (P<0.001). Total race time decreased for men (r(2)=0.17; P=0.043), while it increased for women (r(2)=0.49; P=0.001) across years. The gender difference in overall race time for winners increased from 10% in 1992 to 42% in 2011 (r(2)=0.63; P<0.001). The longitudinal analysis of the five women and five men with the highest number of participations showed that performance decreased in one female (r(2)=0.45; P=0.01). The four other women as well as all five men showed no change in overall race times across years.
  
  
  CONCLUSIONS
  Participation increased and performance improved for male Triple Iron ultra-triathletes while participation remained unchanged and performance decreased for females between 1988 and 2011. The reasons for the increase of the gap between female and male Triple Iron ultra-triathletes need further investigations.
authors.affiliation: Institute of General Practice and for Health Services Research, University of Zurich, Zurich, Switzerland.
authors.forename: Christoph Alexander
authors.initials: CA
authors.lastname: Rüst
authors.forename: Beat
authors.initials: B
authors.lastname: Knechtle
authors.forename: Patrizia
authors.initials: P
authors.lastname: Knechtle
authors.forename: Thomas
authors.initials: T
authors.lastname: Rosemann
authors.forename: Romuald
authors.initials: R
authors.lastname: Lepers