Development of a trail running injury screening instrument (TRISI)
Authors:   , Viljoen Carel Thomas 
Published: January 2023

Trail running is characterised by running on off-road surfaces, in natural environments, and often involves large elevation changes. The consequences of injury in trail running are of concern as medical support in remote regions are challenging. This highlights the importance of identifying trail runners at increased risk for injury before trail running participation in remote regions. It is also important to identify increased injury risk in trail runners not participating in remote regions to design individualised injury risk management strategies. At the start of this research project, limited research evidence was available on injury in trail running.
To determine the epidemiology and clinical characteristics of injury in trail running, a systematic review was conducted (Chapter 2). A wide injury incidence range of 1.6–61.2 injuries per 1000 h of running were reported. The most injured anatomical region reported was the lower limb, mostly affecting the foot. The review highlighted the limited research evidence on injury in shorter distance trail running.
In Chapter 3, the epidemiology, clinical characteristics, and associated injury risk factors were investigated prospectively. An overall injury rate of 19.6 running-related injuries (RRIs) per 1000 h and an RRI mean prevalence of 12.3% were reported. The most injured anatomical site was the lower limb (82.9%), affecting the knee (29.8%). Independent risk factors for RRIs among were a history of previous RRI in the past 12 months (p=0.0032) and having a chronic disease (p=0.0188).
In Chapter 4, the epidemiology, clinical characteristics, and associated injury risk factors were investigated specifically in shorter distance trail runners through analysing an existing dataset. The retrospective annual incidence for gradual onset running-related injuries (GORRIs) was 13%. The most injured anatomical region was the lower limb (94%) with soft tissue injuries accounting for most (83%) GORRIs. Longer race distance (p<0.0001), increasing chronic disease composite score (p=0.0012), and a history of allergies (p=0.0056) were independent risk factors predicting GORRIs.
In Chapter 5, a quantitative multiple methods approach was used to develop the TRISI. The study utilised five phases thorough which 26 risk factors were deemed relevant in trail running. The final TRISI includes risk categories of training, running equipment, demographics, previous injury, behavioural, psychological, nutrition, chronic disease, physiological, and biomechanical factors.
Chapter 6 is a living systematic review that provide an up-to-date summary of the current research evidence regarding injury risk in trail running and of the epidemiology and clinical characteristics of injury in trail running. Currently, eight intrinsic and nine extrinsic risk factors are associated with injury in trail running. The injury incidence range is 0.8 to 61.2 injuries per 1000 h of running and prevalence range is 1.3% to 90%. The most injured anatomical region is the lower limb (83.3%) with the most common injured body areas being foot/toe (55.6%).
In conclusion, I have firstly established the gap in literature regarding the epidemiology and clinical characteristics of injury in trail running through conducting a systematic review. This followed with two original research papers to address the some of the gaps identified and further contributed to determining factors associated with injury among trail runners. I developed a TRISI to be used in future as a clinical decision aid in injury risk management in trail running. Lastly, a living systematic review is conducted to provide up to date evidence to be used in updating the TRISI.