title: Relationship between world-ranking and Olympic performance of swimmers.
abstract: Coaches believe world-ranking lists are a reliable tool for predicting international swimming performance. To examine the relationship between world-ranking and Olympic performance, we modelled world-ranking time and best time from the 2000 Olympic Games for 407 top-50 world-ranked swimmers. Analysis of log-transformed times yielded within-athlete and between-athlete coefficients of variation (CV) and percent changes in performance from world-rankings to Olympics. Variations and performance progressions were compared across sex, stroke, distance, nation and medal status. The within-athlete coefficient of variation of performance for all swimmers was 0.8% (95% confidence limits: 0.7 to 0.9%). Females were slightly less consistent, although not substantially different to males (ratio of female/male within-athlete CV: 1.1; 95% confidence limits: 1.0 to 1.2) and had a wider range of talent (ratio of female/male between-athlete CV: 1.2; 95% confidence limits: 1.1 to 1.4). Swimmers from Australia (AUS) were more consistent than those from the United States (USA) and other nations (OTHER) (ratio of within-athlete CV, USA/AUS: 1.5; 95% confidence limits: 1.0 to 2.2; OTHER/ AUS: 1.6; 95% confidence limits: 1.2 to 2.1). Most Olympic medallists (87%) had a top-10 world-ranking. Overall performance time at the Olympics was slower than world-ranking time by 0.3% (95% confidence limits: 0.2 to 0.4%), medallists improved by 0.6% (95% confidence limits: 0.4 to 0.9%) and non-medallists swam 0.6% slower (95% confidence limits: 0.5 to 0.7%). We conclude that a top-10 ranked swimmer who can improve performance time by 0.6%, equivalent to 0.13 s in the men's 50-m freestyle, will substantially increase their chance of an Olympic medal (the difference between first and fourth place).
authors.affiliation: Department of Physiology, Australian Institute of Sport, PO Box 176, Belconnen, ACT 2616, Australia. cassia_trewin@yahoo.com.au
authors.forename: Cassie B
authors.initials: CB
authors.lastname: Trewin
authors.forename: William G
authors.initials: WG
authors.lastname: Hopkins
authors.forename: David B
authors.initials: DB
authors.lastname: Pyne
mesh_terms: D000124:Achievement; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001363:Awards and Prizes; D003163:Competitive Behavior; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D008297:Male; D010809:Physical Fitness; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012494:Sampling Studies; D012737:Sex Factors; D013550:Swimming; D013647:Task Performance and Analysis