title: Current controversy: analysis of the 2013 FINA World Swimming Championships.
abstract: Anecdotal reports regarding the 2013 Fédération Internationale de Natation World Swimming Championships held in Barcelona suggested that swimming performances were biased, presumably because of a current.
  
  
  OBJECTIVE
  The purpose of this study was to analyze the swimmers' performance data to determine the merit of these rumors.
  
  
  METHODS
  The mean time difference between odd and even 50-m lengths for each lane in the 1500-m freestyle was compared. For each 50-m event, a percent change in performance from the preliminaries to semifinals and semifinals to finals was calculated for all qualifying swimmers. Observations were grouped according to the swimmers' lane assignments.
  
  
  RESULTS
  For the 1500-m freestyle, lane assignment significantly affected the time difference between odd and even 50-m lengths (P < 0.001). The change in performance for the 50-m events was also affected by lane assignment (P < 0.001). When swimmers transitioned from lanes 1-4 for their first swim (preliminaries or semifinals) to lanes 5-8 for their second (semifinals or finals), their performance time improved by 1.11% (95% confidence interval, 0.82%-1.41%), which was significantly greater than any other lane change scenario. When swimmers were in lanes 5-8 for their first swim and lanes 1-4 for their second, their performance time was slower by 0.59% (95% confidence interval, 0.39%-0.80%), which was significantly worse than any other lane change combination.
  
  
  CONCLUSIONS
  Swimmers were advantaged or disadvantaged depending on the direction and lane in which they swam. The existence of a current is the only cause that we can propose to explain these findings. Because one of Fédération Internationale de Natation's primary stated objectives is to provide fairness in competition, new policies are needed to prevent similar biases from occurring in the future.
authors.affiliation: 1Counsilman Center for the Science of Swimming, Department of Kinesiology, Indiana University, Bloomington, IN; and 2School of Health Promotion and Human Performance, Eastern Michigan University, Ypsilanti, MI.
authors.forename: Andrew
authors.initials: A
authors.lastname: Cornett
authors.forename: Christopher
authors.initials: C
authors.lastname: Brammer
authors.forename: Joel
authors.initials: J
authors.lastname: Stager
mesh_terms: D054874:Athletic Performance / Q000502:physiology*; D003163:Competitive Behavior / Q000502:physiology*; D005160:Facility Design and Construction; D006801:Humans; D008297:Male; D013550:Swimming / Q000502:physiology*; D013647:Task Performance and Analysis; D014872:Water Movements