Longitudinal Changes in the Physical Development of Elite Adolescent Rugby Union Players: Effect of Playing Position and Body Mass Change

Abstract

Purpose: The well-being of elite rugby union players has been intensely scrutinised in recent years. Understanding the longitudinal development of physical traits in junior players, alongside the moderating effect of simultaneous increases in body mass, can aid in improving programming and ultimately help junior players prepare for the demands of senior rugby. The purpose of this study was to investigate the longitudinal physical development of elite adolescent backs and forwards in a professional rugby union academy. Methods: A total of 15 players (age, 17.0 [0.2] y; body mass, 90 [14] kg; height, 183 [9] cm; n = 7 backs, n = 8 forwards) completed anthropometric measures and 3 primary performance assessments (countermovement jump, Yo-Yo intermittent recovery test level 1, and 10-m speed) at baseline, year 2, and year 3. Mixed modelling was used to assess player development over time and differences in this development by playing position. Magnitude-based inferencing was used to assess the uncertainty in the effects. Results: There was a substantial increase in countermovement jump height for both groups combined (0.9, ±0.4; standardized improvement, ±90% confidence limits; most likely substantial). Forwards exhibited a moderate-sized decrease in speed (−1.0, ±0.5; very likely substantial), and there was a large difference between groups with regards to speed change with backs outperforming forwards (1.5, ±0.9; very likely substantial). For forward, body mass change had a large negative association with 10-m speed (−1.9, ±0.7; most likely substantial) and Yo-Yo intermittent recovery test level 1 change (−1.2, ±0.9; very likely substantial). Conclusion: These findings provide novel normative data for longitudinal changes in junior rugby union players and suggest that coaches should account for changes in body mass when targeting increases in speed and aerobic fitness.

Testing methods and physical qualities of male age grade rugby union players: A systematic review

“…Twenty-nine studies (69%) directly (n = 7) or indirectly (n = 25) assessed power output within age grade RU players ( Table 5). Jump variations were commonly used to assess lower body power with the vertical jump (VJ) [30,33,34,[36][37][38][41][42][43][44][45][46][48][49][50]63] and countermovement jump (CMJ) [40,47,53,60,[64][65][66][67][68] being most popular. Although similar, the VJ makes use of an arm swing during the movement and is therefore classified as a different test.…”

“…Wall sit Time [37,38] Power 2kg medicine ball throw Distance [37,38] 3kg medicine ball throw Distance [48] 6s Watt Bike Peak power output [69] Bench throw (60% 1RM) Peak power [58] Countermovement jump Height [40,47,53,60,[64][65][66][67][68] Peak power [30,40,60] Force [40,60] Countermovement jump (10kg) Height [53] Horizontal jump Distance [49] Squat jump Height [47,64] Squat jump (60% 1RM) Peak power [58] Triple hop Distance [67] Vertical jump Height [33,34,46,[48][49][50]63,[36][37][38][41][42][43][44][45] Power [41,48] RM Repetition maximum https://doi.org/10.1371/journal.pone.0233796.t005…”

“…Speed 0-5m Velocity [39,40] Acceleration [39,40] Momentum [39,40] 0-10m Velocity [71] Momentum [60,71] 5m Time [39,40,48] 5-10m Velocity [39,40] Acceleration [39,40] Momentum [39,40] 8-12m Velocity [69] Momentum [69] 10m Time [31][32][33][34][35][36][37][39][40][41][42]48,53,57,[59][60][61][64][65][66][67][68] 10-20m Velocity [39,40] Acceleration [39,40] Momentum [39,40] 15m Time [47,72] 20m Time…”

“…Additionally, other aerobic tests that were continuous in nature included the YYE1 [64] and 1500m run [41]. The YYIR1 [37,38,40,59,66,68,73] and 30-15IFT [39,40,73] provided an intermittent assessment of aerobic capacity reported as total distance covered and final running velocity, respectively. Anaerobic endurance.…”

“…A total of thirty-one papers were selected to present and compare the physical qualities of age grade RU players by age grade and position. The analysis included data for the following physical qualities: anthropometrics (height, body mass and body fate percentage), strength (bench press and squat variations), power (VJ height, CMJ height and peak power), speed (10, 20, 30 [37,38,40,59,66,68,73] Anaerobic endurance 400m Time [41] 500m Time [46] 150m shuttle test Distance [67] 250m shuttle test Distance [35] Wingate anaerobic test Peak power [48] Average power Anthropometric qualities. Height and body mass were reported in all thirty-one articles identified for the second aim.…”