Over the last few months I have had three research papers accepted in peer reviewed journals. These research papers were from the last study of my PhD and advance on previous research in talent identification and development, anthropometric and fitness characteristics in youth athletes and junior rugby league by providing a longitudinal evaluation. This research has practical implications for coaches, sport scientists, players and parents and this blog aims to provide a brief overview of the findings of the research and what it means for practice.
My early research demonstrated that within talent identified junior rugby league squads that relatively older (i.e., those players born near the September selection cut off date – See figure below) and earlier maturing (i.e., those players that matured earlier) players were advantaged in selection to these squads (Till et al., 2010a). Further, there were clear physical differences in anthropometric and fitness characteristics between players of differing playing positions and selection levels (i.e., Regional and National players; Till et al., 2010b; 2011). However, to progress on this research and research within other sports it was important to understand the longitudinal changes that occur over time in the development of junior rugby league players.
My first longitudinal study (Till et al., 2012) evaluated the changes in anthropometric and fitness characteristics in 81 junior rugby players aged (13-15 years) and examined these changes by playing position and selection level. Findings identified significant improvement in characteristics between Under 13 and 15 age categories as would be expected with back positions demonstrating greater improvements than forwards over this two year period. This study provided some evidence for tracking the progression of characteristics longitudinally during adolescence, instead of at one-off time points, and considered whether this approach may assist selection and/or performance assessments within rugby league and other youth sport contexts.
My next study (Till et al., 2013a) took a similar approach but evaluated the longitudinal changes of players according to their relative age and maturation status. After complex repeated measures analysis the findings demonstrated that the earlier maturing players outperformed the other players at the under 13s age category but over the two years the later maturing players actually increased their anthropometric (e.g., height) and fitness (e.g., 60m sprint) characteristics more than the other groups. These findings question the early (de)selection policies currently applied in talent identification and development programs when performance-related variables are tracked longitudinally as later maturing players have more chance to improve during the teenage years. Further, during adolescence, maturation status alongside relative age should be considered and controlled for when assessing athlete potential for future progression. Basically, players should be monitored over time and their maturation status should be known.
As these studies had looked at groups of players it was important to understand individual improvements in performance over time. Therefore, my most recent paper (Till et al., 2013) monitored the individual changes in growth and fitness in three case study players of differing maturation status (late, average, early maturer). To do this a performance profile (see figure below) was created using mean data from my previous research (0 represents the mean and +/- 1 represents a standard deviation). Three players anthropometric and fitness testing results were then plotted on this profile at the Under 13s, 14s and 15s age categories to allow comparisons between players.
Findings demonstrated the early maturing player was the best performer at the under 13s age category but when performance was tracked over the two years very different improvements occurred. For example the late maturing player increased height by 9.2% and 60m sprint by -14.9% compared to the early maturing player who demonstrated a 2.0% increase in height and -0.7% in 60m sprint. At the Under 13s age category the early maturing player was 11cm taller and significantly quicker than the late maturing player. However, over the two year period performance significantly changed meaning the late maturing player was now taller and a lot faster than the early maturing player!
This study demonstrated the large variation in the development of anthropometric and fitness characteristics between the three adolescent rugby league players highlighting the importance of longitudinally monitoring individual characteristics during adolescence to assess dynamic changes in growth, maturation and fitness. The findings showcase the limitations of short-term performance assessments at one-off time points within annual-age categories; instead advocating individual development and progression tracking without de-selection. Coaches should consider using an individual approach, comparing data with population averages, to assist in the prescription of appropriate training and lifestyle interventions to aid the development of junior athletes.
The key message from this research is that players should be assessed and monitored over time to track their development instead of using short term, one-off approaches to compare and select players. A performance profile, using existing data or club specific standards is an excellent way of presenting and monitoring player development. Also, the adolescent period, when key maturational changes are occurring, can have significant impact on performance and it is important that coaches, parents and players themselves understand that changes are occurring and this varies from player to player. Again, remember players can always improve and get better and without training to do this then other players will catch up. The later maturing player should never give up as they will catch up in time.
I hope you find this overview of my work interesting and check out the articles for a more in depth read. If you’d like to discuss this further with me then please don’t hesitate to contact me with your questions or comments
Till, K. Cobley, S. O’Hara, J. Chapman, C. & Cooke, C. (2013b) The dynamics of growth and development in junior athletes: An individualised long-term monitoring approach. Journal of Strength & Conditioning Research.
Till, K. Cobley, S. O’Hara, J. Chapman, C. & Cooke, C. (2013a) Considering maturation and relative age in the longitudinal evaluation of junior rugby league players. Scandinavian Journal of Science and Medicine in Sport.
Till, K. Cobley, S. O’Hara, J. Chapman, C. & Cooke, C. (2012) A Longitudinal Evaluation of Anthropometric and Fitness Characteristics in Junior Rugby League Players. Journal of Science and Medicine in Sport.
Till, K. Cobley, S. O’Hara, J. Brightmore, A. Chapman, C. & Cooke, C. (2011) Using Anthropometric and Performance Characteristics to Predict Selection in Junior UK Rugby League Players. Journal of Science and Medicine in Sport. 14, pp. 264-269.
Till, K. Cobley, S. O’Hara, J. Chapman, C. & Cooke, C. (2010b) Anthropometric, physiological and selection characteristics in high performance UK junior Rugby League players. Talent Development and Excellence (special issue). 2(2), pp. 193-207.
Till, K. Cobley, S. Wattie, N. O’Hara, J. Cooke, C. & Chapman, C. (2010a) The prevalence, influential factors and mechanisms of relative age effects in UK Rugby League. Scandinavian Journal of Medicine and Science in Sports. 20. 320-329.