Date of Submission



Background: An emerging trend in adolescent sport is a greater emphasis on identifying and developing talent in young athletes and improving articulation to elite adult participation. Adolescent athletes appear to be increasingly engaged in strenuous training processes thought to best serve these ends. The ability to adapt and recover from strenuous physical loading is finite and influenced by many unique factors during adolescence. Consequently, training and non-training stressors and, or, responses to stressors may exceed individual adaptation thresholds with deleterious, rather than beneficial outcomes. Undesirable consequences of training manifest in complex psychosociobiological signs and symptoms, often defined as overreaching or overtraining along the continuum of athlete adaption. For adolescents, undesirable training responses may impact normal growth and maturation, and athlete development, including participation and performance outcomes. In spite of known risks and increasing anecdotal comment on the adolescent athlete, the extent to which high loads of sports participation during adolescence are related to competitive success, serial fatigue, injury, and overtraining are profoundly under explored and knowledge to guide best practice is lacking. Aims: Within a framework of limited existing empirical evidence and in consultation with Australian Rugby Union, studies included in this thesis aimed to serially monitor participation among three levels of adolescent rugby union players to better understand factors contributing to positive performance and participation outcomes and minimising adverse effects including serial fatigue, injury, training errors, and overtraining in the context of the development of talented young athletes.;Methods: For three separate studies, 75, 106, and 118 participants were recruited from various levels of adolescent rugby involvement that included, school, sports selective school, and state representative rugby. Subjective and objective measures of training volume and intensity, game and training practices, and stress and recovery were collected longitudinally. Results: In study one, representative squad players recorded the highest weekly duration of sport and physical activity (515 REPLACE2 222 min/week), followed by the talent squad (421 REPLACE2 211 min/week) and school boy group (370 REPLACE2 135 min/week). Profiles of individual players identified as group outliers showed weekly durations of 730 REPLACE2 49 min/week for a school boy player, 792 REPLACE2 226 min/week for a representative player, and 804 REPLACE2 335 min/week for a talent squad player, including up to three games and up to eleven training sessions per week for this individual. In study two, players with the highest weekly volume of sport and physical activity during the season demonstrated more favourable recovery-stress states compared with moderate and low volume groups. Despite better psychological stress and recovery profiles of more elite, higher load players, not all participants demonstrated favourable capacities to deal with stress and recovery processes. Seven of 106 participants were in at least two of three categories of highest volume, highest stress and poorest recovery. In study three, time-motion analyses showed that compared with rugby training, rugby games were consistently characterised by more time spent jogging (14 vs. 8%), striding (3.2 vs. 1.3%), and sprinting (1.3 vs. 0.1%) (p<0.001). Players also covered greater distances (4000 REPLACE2 500 vs. 2710 REPLACE2 770 m) and performed more sprints (21.8 vs. 1) during games compared with training (p<0.001).;A major finding of this study is the disparity between physical game demands and on-field rugby training practices in adolescent players. Discussion: High-load participation demands of adolescent athletes may compromise optimal energy balance and compete with physiological, psychological, and time resources available for recovery. In team sports such as rugby, monitoring and quantifying load in individual athletes is necessary to facilitate best practice advice for player management and training prescription. It may be even more critical to monitor individual responses among adolescent athletes, in whom varied internal and external loads exist. Even in the absence of a complete understanding the impact of high volume, high stress, poor recovery participation, these markers may be precursors for more deleterious outcomes such as injury, performance decrements, and overtraining. Internal and external pressures, the transition from 'sampling' to 'specialisation', and over-exaggerated short-term performance goals may contribute to the high participation loads found in some adolescent rugby union players. Conclusion: Growth and maturation and adolescent sports' participation create complex challenges for training and developing young athletes. Accumulative training and non-training stressors with inadequate recovery may exceed individual adaptation thresholds with deleterious, rather than beneficial performance and participation outcomes. It would be advantageous to identify 'at risk' individuals and appropriately manage adolescent athletes within redefined developmental frameworks that prioritise long-term goals, are cognisant of growth and maturation, and systematically aim to prescribe loads and recovery to avoid maladaptations.


School of Exercise Science

Document Type


Access Rights

Open Access


380 pages

Degree Name

Doctor of Philosophy (PhD)


Faculty of Health Sciences