The acute:chronic workload ratio predicts injury: high chronic workload may decrease injury risk in elite rugby league players

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Aim: Investigate whether acute workload (1 week total distance) and chronic workload (4-week average acute workload) predict injury in elite rugby league players. Methods: Data were collected from 53 elite players over two rugby league seasons. The ‘acute:chronic workload ratio’ was calculated by dividing acute workload by chronic workload. A value of greater than 1 represented an acute workload greater than chronic workload. All workload data were classified into discrete ranges by z-scores. Results: Compared with all other ratios, a very-high acute:chronic workload ratio (=2.11) demonstrated the greatest risk of injury in the current week (16.7% injury risk) and subsequent week (11.8% injury risk). High chronic workload (>16 095 m) combined with a very-high 2-week average acute:chronic workload ratio (=1.54) was associated with the greatest risk of injury (28.6% injury risk). High chronic workload combined with a moderate workload ratio (1.02–1.18) had a smaller risk of injury than low chronic workload combined with several workload ratios (relative risk range from 0.3 to 0.7×/÷1.4 to 4.4; likelihood range=88–94%, likely). Considering acute and chronic workloads in isolation (ie, not as ratios) did not consistently predict injury risk. Conclusions: Higher workloads can have either positive or negative influences on injury risk in elite rugby league players. Specifically, compared with players who have a low chronic workload, players with a high chronic workload are more resistant to injury with moderate-low through moderate-high (0.85–1.35) acute:chronic workload ratios and less resistant to injury when subjected to ‘spikes’ in acute workload, that is, very-high acute:chronic workload ratios -1.5.
© Copyright 2016 British Journal of Sports Medicine. BMJ Publishing Group Ltd of the BMA. All rights reserved.

Subjects: sports medicine load rugby injury prophylaxis training competition analysis macrocycle
Notations: biological and medical sciences sport games
DOI: 10.1136/bjsports-2015-094817
Published in: British Journal of Sports Medicine
Published: 2016
Volume: 50
Issue: 4
Pages: 231-236
Document types: article
info graphics
Language: English
Level: advanced