Article Text

Does load management using the acute:chronic workload ratio prevent health problems? A cluster randomised trial of 482 elite youth footballers of both sexes
  1. Torstein Dalen-Lorentsen1,
  2. John Bjørneboe1,
  3. Benjamin Clarsen1,2,
  4. Markus Vagle1,3,
  5. Morten Wang Fagerland1,
  6. Thor Einar Andersen1,4
  1. 1 Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sports Sciences, Oslo, Norway
  2. 2 Department for Disease Burden, Norwegian Institute of Public Health, Bergen, Norway
  3. 3 Department of Sports, Physical Education and Outdoor Studies, University of South-Eastern Norway, Horten, Norway
  4. 4 Department of Sports Medicine, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
  1. Correspondence to Torstein Dalen-Lorentsen, Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sports Sciences, Oslo, Norway; torstein.dalen{at}


Background The acute:chronic workload ratio (ACWR) is commonly used to manage training load in sports, particularly to reduce injury risk. However, despite its extensive application as a prevention intervention, the effectiveness of load management using ACWR has never been evaluated in an experimental study.

Aim To evaluate the effectiveness of a load management intervention designed to reduce the prevalence of health problems among elite youth football players of both sexes.

Methods We cluster-randomised 34 elite youth football teams (16 females, 18 males) to an intervention group (18 teams) and a control group (16 teams). Intervention group coaches planned all training based on published ACWR load management principles using a commercially available athlete management system for a complete 10-month season. Control group coaches continued to plan training as normal. The prevalence of health problems was measured monthly in both groups using the Oslo Sports Trauma Research Centre Questionnaire on Health Problems.

Results The between-group difference in health problem prevalence (primary outcome) was 1.8%-points (−4.1 to 7.7 %-points; p=0.55) with no reduction in the likelihood of reporting a health problem in the intervention group (relative risk 1.01 (95% CI 0.91 to 1.12); p=0.84) compared with the control group.

Conclusions We observed no between-group difference, suggesting that this specific load management intervention was not successful in preventing health problems in elite youth footballers.

Trial registration number ISRCTN18177140.

  • training load
  • football
  • injury prevention
  • soccer
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  • Twitter @torsteindalen, @benclarsen, @markusvagle, @DocThorAndersen

  • Contributors TD-L, BC, TEA, JB and MWF planned the study. The data collection was done by TD-L and MV. All authors have been involved in the data analyses, drafting and revision of the manuscript, and all have approved the final version.

  • Funding The Oslo Sports Trauma Research Center has been established at the Norwegian School of Sport Sciences through generous grants from the Royal Norwegian Ministry of Culture, the South-Eastern Norway Regional Health Authority, the IOC, the Norwegian Olympic Committee and Confederation of Sport and Norsk Tipping AS.

  • Competing interests The Oslo Sports Trauma Research Centre has a research partnership together with Fitstats Inc. This partnership is based on the development of injury surveillance tools, which were not used in this study. Fitstats provided the use of athlete management system free for this study.

  • Patient and public involvement Patients and/or the public were involved in the design, or conduct, or reporting, or dissemination plans of this research. Refer to the Methods section for further details.

  • Patient consent for publication Not required.

  • Ethics approval The study was reviewed by the South-Eastern Norway Regional Committee for Medical and Health Research Ethics (2017/2232) and approved by the ethics board of The Norwegian School of Sports Sciences (39–1 91 217) and the Norwegian Center for Research Data (56935).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information. All data are available as supplementary files.

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