3. Statistical Analyses
All data were tabulated and descriptive data analyses (mean, standard deviation, frequency, range) were performed for the descriptive variables and the number of injuries and matches missed (total, per player, per team). Epidemiologic incidence proportion (also referred to as clinical incidence) and related 95% confidence interval (95% CI) was calculated for each season as the proportion of the number of new players injured during a season relative to the total number of players without injury at the start of the season (10). Repeated measures ANOVA was conducted to examine mean differences in time-loss injuries and matches missed (dependent variables) over five seasons (time as within-subjects factor), computing Bonferroni pairwise comparisons to identify specific differences between seasons (especially for the introduction prior to the start of the 2011 - 2012 season of the “minimum medical standards”). All data analyses were performed using the statistical software IBM SPSS statistics 22.0 for windows.