title: Swimming performances in long distance open-water events with and without wetsuit.
abstract: BACKGROUND
  Existing literature showed improved swimming performances for swimmers wearing wetsuits competing under standardized conditions in races held in pools on short to middle distances. Data about the influence of wetsuits on swimming performances in long and ultra-long open-water swimming races are missing. It is unknown whether the benefit of wearing wetsuits is comparable in men and women. The aim of this study was to investigate the influence of wearing a wetsuit on open-water swimming performances at the 26.4 km 'Marathon Swim in Lake Zurich' in Lake Zurich, Switzerland, and the 3.8 km Lake Ontario Swim Team-Race (LOST-Race) in Lake Ontario, Canada.
  
  
  METHODS
  Race times of the fastest female and male swimmers competing with and without wetsuit were compared using multi-level regression analyses and analysis of variance.
  
  
  RESULTS
  In the 'Marathon Swim' in Lake Zurich, wearing a wetsuit had no effect on race time regarding the gender where athletes wearing a wetsuit were not faster than athletes without wetsuit. However, the ten fastest men wearing a wetsuit (410.6 ± 26.7 min) were faster (32.7%, p < 0.01) than the ten fastest women without wetsuit (544.9 ± 81.3 min). In the 'LOST-Race', the top ten men wearing a wetsuit (51.7 ± 2.5 min) were faster (13.2%, p < 0.01) than the top ten women wearing a wetsuit (58.5 ± 3.2 min). Additionally, the top ten men without wetsuit (52.1 ± 2.4 min) were faster (19.6%, p < 0.01) than the top ten women without wetsuit (62.3 ± 2.5 min). The top ten women wearing a wetsuit (58.5 ± 3.2 min) were faster (6.5%, p < 0.01) than top ten women without a wetsuit (62.3 ± 25 min).
  
  
  CONCLUSIONS
  These results suggest that wearing a wetsuit had a positive influence on swimming speed for both women and men but the benefit of the use of wetsuits seemed to depend on additional factors (i.e. race distance). Women seemed to benefit more from wearing wetsuits than men in longer open-water ultra-distance swimming races.
authors.affiliation: Institute of General Practice and for Health Services Research, University of Zurich, Zurich, Switzerland.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Ulsamer
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.affiliation: Institute of General Practice and for Health Services Research, University of Zurich, Zurich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rosemann
authors.affiliation: INSERM U1093, Faculty of Sport Sciences, University of Burgundy, Dijon, France.
authors.forename: Romuald
authors.initials: R
authors.lastname: Lepers
authors.affiliation: Facharzt FMH für Allgemeinmedizin, Vadianstrasse 26, Gesundheitszentrum St. Gallen, St. Gallen, Switzerland.
authors.forename: Beat
authors.initials: B
authors.lastname: Knechtle
keywords: Ironman; Neoprene suit; Swim performance; Swimming; Ultra-endurance