Dynamic balance performance varies by position but not by age group in elite Rugby Union players - a normative study

This cohort study aimed to provide normative Y Balance Test scores for an elite Rugby Union population, while investigating the effect player age groups (senior/under-20), playing positions (forwards/backs) and anthropometrics (height and body mass) had on performance. Two-hundred and sixty-one elite male under-20 (n=50) and senior (n=211) players completed baseline Y Balance Test during the 2015/2016 season. One-way ANCOVA and post-hoc t-tests were used to investigate the effect playing position, player group, height and weight had on performance. The cohort was then stratified into groups (age group and/or playing position), and normative percentiles were presented. There was a statistically significant difference (p<0.05) in Y Balance Test performance between playing positions, when controlling for age group. This difference did not remain when controlling for player body mass. Post-hoc analysis demonstrated that backs had a longer normalised reach distance, with medium-large and small-medium effect sizes for the under-20 and senior cohorts respectively. The one-way ANCOVA analysis suggests that this difference is likely due to the larger differences in player body mass between forward and back playing positions. The normative values presented in this paper may be used by clinicians and researchers to aid injury prevention and rehabilitation strategies.