title: Do physical qualities influence the attainment of professional status within elite 16-19 year old rugby league players?
abstract: OBJECTIVE
  The current study retrospectively compared the physical qualities of elite academy rugby league players (aged 16-19 years) by career attainment level (i.e., academy or professional).
  
  
  METHODS
  Retrospective cross-sectional and longitudinal design.
  
  
  METHODS
  Eighty-one academy rugby league players were assessed for physical qualities (height, body mass, skinfolds, speed, momentum, vertical jump, Yo-Yo Level 1 and 1-RM squat, bench press and prone row) at the Under 17-19 age categories between 2007 and 2012. Player's career attainment level was determined in 2014. Longitudinal changes in physical qualities between Under 17 and 19s were compared by career attainment level.
  
  
  RESULTS
  Professional players demonstrated moderate significant advantages for height (d=0.98) and 1-RM squat (d=0.66) at the Under 17s, 1-RM bench press (d=0.76) at the Under 18s and 1-RM prone row (d=0.73) at the Under 19s age categories when compared to academy players. When assessed longitudinally (Under 17s-19s), professional players significantly outperformed academy players for 1-RM squat (η(2)=0.20). Professional players also demonstrated greater increases in body mass (8.2 vs. 2.9kg) and 10m momentum (47 vs. 17kgs(-1)) than academy players between the Under 17s and 19s.
  
  
  CONCLUSIONS
  Advanced physical qualities, particularly height and absolute strength, within 16-19 year old players may contribute to attaining professional status in rugby league. Further, the development of body mass and momentum for players within an academy is an important consideration in the progress towards professional rugby league. Therefore, practitioners should aim to identify and develop the physical qualities, especially size and strength, within academy rugby league players.
authors.affiliation: Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, United Kingdom. Electronic address: k.till@leedsbeckett.ac.uk.
authors.forename: Kevin
authors.initials: K
authors.lastname: Till
authors.affiliation: Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, United Kingdom.
authors.forename: Ben
authors.initials: B
authors.lastname: Jones
authors.affiliation: Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, United Kingdom.
authors.forename: Tom
authors.initials: T
authors.lastname: Geeson-Brown
mesh_terms: D000293:Adolescent; D054874:Athletic Performance / Q000706:statistics & numerical data; D001824:Body Constitution / Q000502:physiology*; D002322:Career Mobility; D015444:Exercise / Q000502:physiology*; D005538:Football / Q000145:classification / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D053580:Muscle Strength / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D012189:Retrospective Studies; D055815:Young Adult
keywords: Academy; Strength; Talent development; Talent identification