title: Evaluation of goal kicking performance in international rugby union matches.
abstract: OBJECTIVE
  Goal kicking is an important element in rugby but has been the subject of minimal research. To develop and apply a method to describe the on-field pattern of goal-kicking and rank the goal kicking performance of players in international rugby union matches.
  
  
  METHODS
  Longitudinal observational study.
  
  
  METHODS
  A generalized linear mixed model was used to analyze goal-kicking performance in a sample of 582 international rugby matches played from 2002 to 2011. The model adjusted for kick distance, kick angle, a rating of the importance of each kick, and venue-related conditions.
  
  
  RESULTS
  Overall, 72% of the 6769 kick attempts were successful. Forty-five percent of points scored during the matches resulted from goal kicks, and in 5.7% of the matches the result of the match hinged on the outcome of a kick attempt. There was an extremely large decrease in success with increasing distance (odds ratio for two SD distance 0.06, 90% confidence interval 0.05-0.07) and a small decrease with increasingly acute angle away from the mid-line of the goal posts (odds ratio for 2 SD angle, 0.44, 0.39-0.49). Differences between players were typically small (odds ratio for 2 between-player SD 0.53, 0.45-0.65).
  
  
  CONCLUSIONS
  The generalized linear mixed model with its random-effect solutions provides a tool for ranking the performance of goal kickers in rugby. This modelling approach could be applied to other performance indicators in rugby and in other sports in which discrete outcomes are measured repeatedly on players or teams.
authors.affiliation: New Zealand Rugby Union, New Zealand; Sport Performance Research Institute New Zealand, Auckland University of Technology, New Zealand. Electronic address: ken.quarrie@nzrugby.co.nz.
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Quarrie
authors.affiliation: Sport Performance Research Institute New Zealand, Auckland University of Technology, New Zealand.
authors.forename: Will G
authors.initials: WG
authors.lastname: Hopkins
mesh_terms: D005538:Football / Q000502:physiology / Q000706:statistics & numerical data*; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D035002:Lower Extremity / Q000502:physiology
keywords: Football; Generalized linear mixed model; Performance indicators