Determination and comparison of anthropometric, physiological and psychological performance measures in elite youth Rugby Union players at four different stages of professional development across three time points during a competitive season and the longitudinal changes of each age group

Understanding the development of talented youth Rugby Union players in Pathway and Academy settings is important for their continued preparation and support to aid the transition of these players into professional rugby (Kobal, et al., 2016). The aims of this study were to: (i) document and compare anthropometric, physiological and psychological capacities in Scottish Rugby Union (SRU) elite players between 4 developmental levels and (ii) compare within each level across the season. With institutional ethics approval, Under 16 (U16, N=18), Under 18 (U18, N=16), BT Academy Stage 2 (BAS2, N=9) and BT Academy Stage 3 (BAS3, N=12) players completed 3 testing points over 2016-2017 season (pre, mid and post). Measures of anthropometric (body mass, percentage body fat and fat free mass), functional movement (tuck jump), lower body power (counter movement jump (CMJ)), strength (3 repetition maximum (RM) squat, bench and chin), speed (10m & 30m sprint, 10m momentum), aerobic fitness (YoYo Intermittent Recovery Test-1), anaerobic endurance (Repeated Sprint Ability), agility (505) and psychological (Sports Mental Toughness Questionnaire (SMTQ)) characteristics were completed. In the pre-season test results indicated that most statistically significant differences between playing levels occurred between BAS3 v U16 and BAS3 v U18 levels in body mass (95% Confidence Intervals of difference (2.1, 29.5 kg) and (3.2, 33.8 kg)) respectively, FFM ((1.4, 23.0 kg) and (6.4, 28.2 kg)), CMJ ((8.0, 18.6 cm) and (1.2, 18.6 cm)), when allometrically scaled, 3RM Squat ((250.4, 527.4 AU) and (175.6, 483.8 AU)), 3RM Bench ((40.6, 71.9 AU) and (28.4, 61.8 AU)), 3RM Chin ((84.5, 297.9 AU) and (73.1, 296.4 AU)) and 10m Momentum ((14.1, 169.4 kgm/s) and (25.8, 199.4 kgm/s)). BAS3 were significantly faster over 30m than the U16 cohort (-0.53, 0.04 s). A similar pattern was evident in mid and late season. At the mid-point of the season it was apparent after analysing test scores that, BAS3 and BAS2 had significantly greater power than U16 (CMJ, (4.3, 19.3 cm), (2.6, 17.6 cm)). The BAS3 cohort during testing recorded a greater Total Mental Toughness score than the U16 cohort (0.1, 6.0 AU). Repeated Measures ANOVA showed no statistically significant changes for agility, speed, aerobic or anaerobic fitness across the season at any playing level although large effect sizes were evident. The U16 Whole Squad significantly improved 3RM Bench (2.0, 16.7 kg) across the season. Total Mental Toughness scores improved for U18 (0.1, 6.0 AU), BAS2 (2.0, 7.0 AU) and BAS3 (0.1, 16.0 AU). As hypothesised, BAS3 recorded the most differences compared to the lower pathway levels (Darrall-Jones, et al., 2015). At each time point the BAS3 players were stronger, had greater lower body power and lean mass; however they did not demonstrate as having greater agility, aerobic fitness or anaerobic endurance than the junior players. Where no differences were found in characteristics between Academy and Pathway levels, and no changes across season, even where differences would be expected (e.g. body fat percentage and anaerobic endurance), greater focus can be made on these aspects of development in training