C.T. Viljoen1,2,3, D.C. Janse van Rensburg4,3, W. Van Mechelen2,5,6,7, E. Verhagen2, E. Korkie1,3, T. Cronje8
1University of Pretoria, Physiotherapy, Pretoria, South Africa, 2Amsterdam Collaboration for Health and Safety in Sports, Department of Public and Occupational Health, Amsterdam Movement Sciences, Amsterdam University Medical Centers, Location VU University Medical Center, Amsterdam, Netherlands, 3Sport, Exercise Medicine and Lifestyle Institute (SEMLI), Pretoria, South Africa, 4University of Pretoria, Section Sports Medicine, Pretoria, South Africa, 5University of Queensland, School of Human Movement and Nutrition Sciences, Faculty of Health and Behavioural Sciences, Brisbane, Australia, 6University of Cape Town, Division of Exercise Science and Sports Medicine (ESSM), Department of Human Biology, Faculty of Health Sciences, Cape Town, South Africa, 7University College Dublin, School of Public Health, Physiotherapy and Population Sciences, Dublin, Ireland, 8University of Pretoria, Department of Statistics, Faculty of Natural and Agricultural Sciences, Pretoria, South Africa
Background: Trail runners are exposed to uneven and varying running surfaces, large elevation changes, and environmental hazards. Runners cover large geographical regions, often in remote areas where medical evacuation is challenging. Limited literature reports prospectively on running-related injuries (RRIs) among trail runners. There is a need to investigate the epidemiology and associated risk factors of RRIs among trail runners to help guide appropriate injury prevention strategies.
Purpose: To prospectively investigate the epidemiology and associated risk factors of injury among trail runners participating in training and racing, mainly in South Africa.
Methods: This prospective cohort study used a dynamic sampling method and utilised the Oslo Sports Trauma Research Centre Questionnaire on Health Problems (OSTRC-H) to register RRIs two-weekly over 15 follow-up periods (30 weeks). The characteristics of the demographic profile, running exposure, and response rate of the participants were reported as means (95%CI). We recorded the two-weekly mean prevalence (% runners; 95%CI) and frequency of RRI characteristics (% of RRIs) for anatomical region, body area, tissue type, and pathology type; injury severity grade (mean OSTRC-H score; 95%CI), and associated injury risk factors (OR; p-value).
Results: 151 trail runners participated with a mean response rate of 67.6% over the 15 two-week follow-up periods. We recorded a total of 370 RRIs with 71.5% of participants reporting at least one injury. The mean prevalence of all RRIs reported was 23.7% with sudden onset RRIs showing a higher prevalence per two-week period (12.5%) compared to gradual onset RRIs (10.0%). The overall injury rate was 37.2 RRIs per 1000h of running with a mean severity score (maximum of 100) of 48.0. The most commonly injured anatomical region was the lower limb (83.8%). Common injuries by body region involved the knee (31.1%), lower leg (17.6%), and foot (16.5%). The most common injured tissue type was muscle/tendon (57.6%) with specific pathology types comprising tendinopathy (36.2%) and muscle injury (18.4%). Independent injury risk factors included current RRI (OR=1.989; p=0.0389) and RRI in the past 12 months (OR=3.028; p=0.0061), while a higher number of running sessions was a protective factor (OR=0.808: p<0.0001).
Conclusion(s): Almost ¾ of trail runners reported at least one injury over a 30-week period. The lower limb was mostly affected, specifically the knee, lower leg and foot. Current and previous RRI were independent risk factors for sustaining trail RRIs while a higher number of running sessions per two-week period seems to be a protective factor. To our knowledge, this was the first prospective cohort study where trail runners were exposed to a wide variety of running surfaces (mountain, desert, beach, forest).
Implications: Current and previous RRIs increase the risk of sustaining another RRI. Physical therapists need to focus on optimal rehabilitation of injured runners in order to restore sport-specific tissue loading capacity to prevent the occurrence or reoccurrence of RRIs. A higher number of running sessions seems to be a protective factor. However, considering the complexity of sport injury, higher running sessions can only be a protective factor if we consider other variables like the total running distance and running intensity.
Funding, acknowledgements: No funding
Keywords: Trail running, Running-related injuries, Epidemiology
Topic: Sport & sports injuries
Did this work require ethics approval? Yes
Institution: University of Pretoria
Committee: Research Ethics Committee, Faculty of Health Sciences
Ethics number: 469/2018
All authors, affiliations and abstracts have been published as submitted.
