title: Race Factors Affecting Performance Times in Elite Long-Track Speed Skating.
abstract: Analysis of sport performance can provide effects of environmental and other venue-specific factors in addition to estimates of within-athlete variability between competitions, which determines smallest worthwhile effects.
  
  
  OBJECTIVE
  To analyze elite long-track speed-skating events.
  
  
  METHODS
  Log-transformed performance times were analyzed with a mixed linear model that estimated percentage mean effects for altitude, barometric pressure, type of rink, and competition importance. In addition, coefficients of variation representing residual venue-related differences and within-athlete variability between races within clusters spanning ~8 d were determined. Effects and variability were assessed with magnitude-based inference.
  
  
  RESULTS
  A 1000-m increase in altitude resulted in very large mean performance improvements of 2.8% in juniors and 2.1% in seniors. An increase in barometric pressure of 100 hPa resulted in a moderate reduction in performance of 1.1% for juniors but an unclear effect for seniors. Only juniors competed at open rinks, resulting in a very large reduction in performance of 3.4%. Juniors and seniors showed small performance improvements (0.4% and 0.3%) at the more important competitions. After accounting for these effects, residual venue-related variability was still moderate to large. The within-athlete within-cluster race-to-race variability was 0.3-1.3%, with a small difference in variability between male (0.8%) and female juniors (1.0%) and no difference between male and female seniors (both 0.6%).
  
  
  CONCLUSIONS
  The variability in performance times of skaters is similar to that of athletes in other sports in which air or water resistance limits speed. A performance enhancement of 0.1-0.4% by top-10 athletes is necessary to increase medal-winning chances by 10%.
authors.affiliation: Faculty of Behavioral and Movement Sciences, Vrije Universiteit University Amsterdam, MOVE Research Inst Amsterdam, Amsterdam, The Netherlands.
authors.forename: Dionne A
authors.initials: DA
authors.lastname: Noordhof
authors.forename: Roy C
authors.initials: RC
authors.lastname: Mulder
authors.forename: Jos J
authors.initials: JJ
authors.lastname: de Koning
authors.forename: Will G
authors.initials: WG
authors.lastname: Hopkins
mesh_terms: D000531:Altitude; D054874:Athletic Performance / Q000502:physiology*; D003163:Competitive Behavior / Q000502:physiology*; D004777:Environment; D005260:Female; D006801:Humans; D008297:Male; D012861:Skating / Q000502:physiology*; D013997:Time Factors