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Training Load and Injury: Causal Pathways and Future Directions

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A Letter to the Editor to this article was published on 22 July 2021

A Letter to the Editor to this article was published on 22 July 2021

Abstract

Causal pathways between training loads and the mechanisms of tissue damage and athletic injury are poorly understood. Here, the relation between specific training load measures and metrics, and causal pathways of gradual onset and traumatic injury are examined. Currently, a wide variety of internal and external training load measures and metrics exist, with many of these being commonly utilized to evaluate injury risk. These measures and metrics can conceptually be related to athletic injury through the mechanical load-response pathway, the psycho-physiological load-response pathway, or both. However, the contributions of these pathways to injury vary. Importantly, tissue fatigue damage and trauma through the mechanical load-response pathway is poorly understood. Furthermore, considerable challenges in quantifying this pathway exist within applied settings, evidenced by a notable absence of validation between current training load measures and tissue-level mechanical loads. Within this context, the accurate quantification of mechanical loads holds considerable importance for the estimation of tissue damage and the development of more thorough understandings of injury risk. Despite internal load measures of psycho-physiological load speculatively being conceptually linked to athletic injury through training intensity and the effects of psycho-physiological fatigue, these measures are likely too far removed from injury causation to provide meaningful, reliable relationships with injury. Finally, we used a common training load metric as a case study to show how the absence of a sound conceptual rationale and spurious links to causal mechanisms can disclose the weaknesses of candidate measures as tools for altering the likelihood of injuries, aiding the future development of more refined injury risk assessment methods.

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Acknowledgements

The authors would like to thank Blake McLean, Michael Rennie, Emily Matijevich, and Brook Kalkhoven for their contributions to the manuscript.

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Authors and Affiliations

  1. School of Sport, Exercise and Rehabilitation, Human Performance Research Centre, Faculty of Health, University of Technology Sydney, Moore Park Precinct, Broadway, Ultimo, PO Box 123, Sydney, NSW, 2007, Australia

    Judd T. Kalkhoven, Mark L. Watsford, Aaron J. Coutts & Franco M. Impellizzeri

  2. Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada

    W. Brent Edwards

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  1. Judd T. Kalkhoven
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  2. Mark L. Watsford
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  3. Aaron J. Coutts
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  4. W. Brent Edwards
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  5. Franco M. Impellizzeri
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Correspondence to Judd T. Kalkhoven.

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Conflict of Interest

Judd Kalkhoven, Mark Watsford, Aaron Coutts, W. Brent Edwards and Franco Impellizzeri declare that they have no conflicts of interest.

Author contributions

JTK conceived the idea for the article, wrote the first draft of the manuscript and all versions thereafter. MLW contributed substantially to the editing and conceptual direction of the manuscript. AJC contextualised the information provided in the manuscript within the current climate of training load research. WBE contributed to the tissue engineering and mechanical load components of the manuscript. FMI contributed to the conceptual formation and editing of the manuscript as a whole with a special emphasis to Sect. 3. All authors read and approved the final manuscript.

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No sources of funding were used to assist in the preparation of this article.

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Data sharing is not applicable to this article as no datasets were generated or analysed during the current study.

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Kalkhoven, J.T., Watsford, M.L., Coutts, A.J. et al. Training Load and Injury: Causal Pathways and Future Directions. Sports Med 51, 1137–1150 (2021). https://doi.org/10.1007/s40279-020-01413-6

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  • DOI: https://doi.org/10.1007/s40279-020-01413-6

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