Position-specific characteristics for elite adolescent male rugby players in the North West province

Abstract

The purpose of this study was to identify position- and age-specific anthropometric, physical and motor characteristics of 15- to 18-year-old elite adolescent male South African Rugby Union players in the North West province. Players were compared to determine if anthropometric (body mass, stature, selected skinfolds, girth measurements, sum of skinfolds, percentage body fat and percentage muscle mass), physical (explosive power, strength, strength endurance) and motor (speed and aerobic endurance) characteristics differentiated between playing positions and age groups. The following age groups: u/15 (N=190), u/16 (N=164) and u/18 (N=192) were divided into six positional groups, namely front row (positions 1, 2 and 3) (N=109), locks (positions 4 and 5) (N=56), loose forwards (positions 6, 7 and 8) (N=142), halves (positions 9 and 10) (N=69), centres (positions 12 and 13) (N=74) and outside backs (positions 11, 14 and 15) (N=96). Descriptive statistics (means, standard deviations) were calculated from cross-sectional data for anthropometric, physical and motor characteristics. A hierarchical linear model (mixed model) was used to determine if any positional and age group differences were practically significant by means of Cohen's effect size (ES). An effect size of 0.2 was considered as small, 0.5 as medium and 0.8 as large (Cohen, 1988). The mean (x̄) for each playing position and age group was calculated and used to evaluate each player according to his own age group and playing position. Positional differences occurred between the u/15, u/16 and u/18 players: forward players (front row, locks and loose forwards) showed higher values in most of the anthropometric characteristics compared to the back line players (halves, centres and outside backs) and also showed better values in most of the age groups for strength (1 RM bench press, 1 RM back squat and 1 RM RFE left and right leg). Large practically significant differences occurred when the u/15 players were compared to the u/18 players. The u/16 players performed better than the u/18 players in the following positional groups: front row players performed better in the aerobic endurance test, locks and loose forwards performed better in the 10- and 40 m speed test, centres performed better in the 40 m speed and aerobic endurance test. Halves and outside backs performed better in the 10 m speed and aerobic endurance test. All the u/18 positional groups, except for the centres, performed better in the upper and lower body strength tests when compared to the u/15 and u/16 players. The results, therefore, indicate that practically significant differences in playing positions and age groups exist with regard to anthropometric, physical and motor characteristics. These findings can serve as a valuable normative data scale for RU players in these age groups in the North West province. Mean scores can be used as guidelines to assist coaches, selectors and sport scientists with team selection, physical preparation and talent identification. Coaches and sport scientists should be familiarized with the effect of growth and maturation among adolescents when players are selected for specific teams and playing positions. However, to compile an accurate norm scale for all Rugby Union players for the age groups u/15, u/16 and u/18, it is strongly recommended to use players from all provinces in South Africa.