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Poor isometric neck extension strength as a risk factor for concussion in male professional Rugby Union players
  1. Theo Farley1,2,
  2. Ed Barry3,
  3. Richard Sylvester2,4,
  4. Akbar De Medici2,
  5. Mathew G Wilson1,2
  1. 1 Division of Surgery and Interventional Science, University College London, London, UK
  2. 2 Institute of Sport, Exercise and Health (ISEH), University College London, London, London, UK
  3. 3 Georgia Rugby Federation, Tbilisi, Georgia
  4. 4 National Hospital for Neurology and Neurosurgery, London, UK
  1. Correspondence to Theo Farley, Division of Surgery and Interventional Science, University College London, London, UK; Theo_farley{at}


Background Concussion is one of the highest burden injuries within professional Rugby Union (‘rugby’) and comes with a high health and financial cost to players and teams. Limited evidence exists as to the existence of modifiable intrinsic risk factors for concussion, leaving athletes and clinicians with few options when developing prevention strategies.

Objective To investigate whether neck strength is significantly associated with concussion incidence in professional male rugby players.

Methods 225 rugby players were assessed for neck strength at three time points throughout the 2018/2019 season using a method of isometric contraction. Associations with clinically diagnosed concussion injuries are presented as incidence rate ratios (IRRs) with 95% CIs.

Results Thirty concussions occurred in 29 players during the study period; a rate of 13.7 concussions per 1000 hours played. Greater neck strength was observed at mid and end of season time points versus preseason across the study population. There was a significant association between extension strength and concussion; a 10% increase for extension strength was associated with a 13% reduction in concussion rate (adjusted IRR (95% CI) 0.87 (0.78 to 0.98). No other significant associations were observed between concussion incidence and any other unique neck strength range or composite score.

Conclusion Higher neck extension strength is associated with lower concussion rates in male rugby players. Neck strength is a modifiable intrinsic risk factor for concussion and may be an important component of a strength and conditioning regime.

  • isometric
  • neck
  • strength
  • brain concussion

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  • Collaborators There were no collaborating groups involved in this study.

  • Contributors TF conceptualised the study methods and along with EB, undertook data collection. TF wrote the original draft of the manuscript. All authors analysed the data and supported the construction of the manuscript. All authors read and approved the final copy of the manuscript. TF is the guarantor

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

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

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.