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Variable and Changing Trajectories in Youth Athlete Development: Further Verification in Advocating a Long-term Inclusive Tracking Approach

Cobley, Stephen P.1; Till, Kevin2; O'Hara, John2; Cooke, Carlton2; Chapman, Chris3

Journal of Strength & Conditioning Research:
doi: 10.1519/JSC.0000000000000353
Original Research

Abstract: Cobley, SP, Till, K, O'Hara, J, Cooke, C, and Chapman, C. Variable and changing trajectories in youth athlete development: Further verification in advocating a long-term inclusive tracking approach. J Strength Cond Res 28(7): 1959–1970, 2014—Athlete development through adolescence can vary greatly because of maturational processes. For example, variation can be observed in anthropometric and fitness measures with later maturing individuals “catching up” their earlier maturing peers at later time points. This study examined a methodological issue concerning how best to assess anthropometric and fitness change (i.e., “across age categories” or “per year”) relative to an age and skill-matched population (N = 1,172). Furthermore, it examined changes in anthropometric and fitness characteristics in 3 cases of youth rugby league players (aged 13–15) across a 2-year period. Findings identified the “per year” method as generating less deviated z-scores across anthropometric and fitness measures (e.g., mean change p < 0.001), suggesting less substantial change in case players relative to the population. When applied to additional players, z-score and radar graphs showed developmental variability and longitudinal change. The possibility of a “later maturing player” increasing anthropometric (e.g., height: player 4 = 3.3 cm; player 5 = 13.2 cm; and player 6 = 15.7 cm) and fitness (e.g., 30-m sprint: player 4 = −0.18 s, player 5 = −0.46 s, and player 6 = −0.59 s) characteristics compared with early maturing players was confirmed. Findings affirm the potential for variable and changing trajectories in adolescent athletes. Practical implications advocate a long-term inclusive tracking approach of athletes, the avoidance of (de)selection, and the reduction of a performance emphasis in adolescent stages of sport systems.

Author Information

1School of Exercise & Sport Science, Faculty of Health Sciences, The University of Sydney, Sydney, Australia;

2Research Institute of Sport, Physical Activity, & Leisure, Leeds Metropolitan University, Leeds, United Kingdom; and

3Rugby Football League, Red Hall, Leeds, United Kingdom

Address correspondence to Dr. Stephen Cobley,

Copyright © 2014 by the National Strength & Conditioning Association.