Damsted C1, Glad S2, Nielsen RO1, Sørensen H1, Malisoux L3.
1 Section of Sport Science, Department of Public Health, Aarhus University, Aarhus, Denmark.
2 University College Lillebaelt, Odense, Denmark.
3 Sports Medicine Research Laboratory, Department of Population Health, Luxembourg Institute of Health, Luxembourg.
Sudden changes (increases and decreases) in training load have been suggested to play a key role in the development of running-related injuries. However, the compiled evidence for an association between change in training load and running-related injury does not exist.
The purpose of the present systematic review was to compile the evidence from original articles examining the association between changes in training load and running-related injuries.
Four databases (Pubmed/Medline, SPORTDiscus, Embase, and Scopus) were systematically searched. Two reviewers screened titles, abstracts, and full-text articles independently. Articles were included if i) the study design was a randomized trial, a prospective cohort study, a cross-sectional study or a case-control study, ii) participants were runners between 18-65 years, and iii) specific information on changes in training load was provided. Methodological quality of included articles was assessed using the Newcastle Ottawa Scale and the PEDro rating scale.
Four articles fulfilled the eligibility criteria of which three found an association between increases in training load and an increased risk of running-related injuries: This association was shown by an increased injury risk amongst runners: i) if they recently had performed one or more changes in either velocity and/or distance and/or frequency compared with the non-injured runners (p = 0.037), ii) increasing their average weekly running distance by more than 30% compared to an increase less than 10% (Hazard Ratio = 1.59 (95% Confidence Interval: 0.96; 2.66)), iii) increasing their total running distance significantly more the week before the injury origin compared with other weeks (mean difference: 86%; 95% Confidence Interval: 12%; 159%, p = 0.026). However, no difference was found between a 10% and a 24% average increase in weekly volume (HR = 0.8, 95% CI: 0.6; 1.3).
Very limited evidence exists supporting that a sudden change in training load is associated with increased risk of running-related injury.
LEVEL OF EVIDENCE:
Etiology; running-related injuries; training load