Title

Seasonal change in bone, muscle and fat in professional rugby league players and its relationship to injury: a cohort study

Date of this Version

11-6-2012

Document Type

Journal Article

Publication Details

Published version

Georgeson, E.C., Weeks, B.K., McLellan, C., Beck, B.R. (2012). Seasonal change in bone, muscle and fat in professional rugby league players and its relationship to injury: a cohort study. BMJ Open, 2, e001400, 1-8

Access the journal

2012 HERC submission. FoR codes: 110602; 110604

© Copyright The Authors, 2012

ISSN

2044-6055

Abstract

Objectives: To examine the anthropometric characteristics of an Australian National Rugby League team and identify the relationship to type and incidence of injuries sustained during a professional season. It was hypothesised that body composition would not change discernibly across a season and that injury would be negatively related to preseason bone and muscle mass.

Design: A repeated measure, prospective, observational, cohort study. Setting: Griffith University, Gold Coast, Australia.

Participants: 37 professional male Australian National Rugby League players, 24.3 (3.8) years of age were recruited for preseason 1 testing, of whom 25 were retested preseason 2. Primary and secondary outcome measures: Primary outcome measures included biometrics; body composition (bone, muscle and fat mass; dual-energy x-ray absorptiometry; XR800, Norland Medical Systems, Inc); bone geometry and strength (peripheral quantitative CT; XCT 3000, Stratec); calcaneal broadband ultrasound attenuation (BUA; QUS-2, Quidel); diet and physical activity history. Secondary outcome measures included player injuries across a single playing season.

Results: Lean mass decreased progressively throughout the season (pre=81.45(7.76) kg; post=79.89(6.72) kg; p≤0.05), while whole body (WB) bone mineral density (BMD) increased until mid-season (pre=1.235(0.087) g/cm2; mid=1.296(0.093) g/cm2; p≤0.001) then decreased thereafter (post=1.256(0.100); p≤0.001). Start-of-season WB BMD, fat and lean mass, weight and tibial mass measured at the 38% site predicted bone injury incidence, but no other relationship was observed between body composition and injury.

Conclusions: Significant anthropometric changes were observed in players across a professional rugby league season, including an overall loss of muscle and an initial increase, followed by a decrease in bone mass. Strong relationships between anthropometry and incidence of injury were not observed. Long-term tracking of large rugby league cohorts is indicated to obtain more injury data in order to examine anthropometric relationships with greater statistical power.

 

This document has been peer reviewed.