In recent years participation in mass community-based endurance running events has grown significantly.  And although there are numerous health-benefits, distance running is also associated with the development of injuries sustained from repetitive loading, combined with insufficient recovery time – referred to as “gradual onset running related injuries” (GORRIs).  Risk factors that might cause these injuries include age, sex, body mass index, previous injury, physical fitness, psychological factors, running volume, intensity, and frequency, the environment, and footwear. Although several risk factors for developing GORRIs have been reported, researchers of 2 studies recently published, wanted to investigate risk factors predictive of a history of GORRIs in ultramarathon (races longer than 42.2 km) road runners, and in trail runners. These studies collected data from 29 585 participants of the 56 km Two Oceans ultramarathon and 2824 entrants of the Two Oceans trail races from 2012 to 2015. They found that there were some novel risk factors not reported before, that could predict a history of GORRIs – these are ‘a history of multiple chronic diseases’ and ‘a history of any allergies’. In trail runners an additional risk factor was also ‘longer race distance’. When it comes to chronic disease, it was found that for every 2 additional chronic diseases present, the prevalence of GORRIs increased 1.6 times in the trail running cohort, and 2.3 times in the road running group.  In the road running group, researchers were also able to identify that a history of certain chronic diseases, particularly GIT disease, respiratory disease, a history of CVD, symptoms of CVD, and any nervous system/psychiatric disease, was predictive of an increased risk for developing a GORRI in the ultramarathon race entrants. And although finding the reasons why chronic disease is a risk factor for injuries in runners was not the aim of the study, the authors do explain that there is indirect evidence that chronic diseases or medications used to treat chronic diseases, have been found to be related to tendinopathies, ligament injuries, skeletal muscle myopathy, and bone stress injuries. In addition to identifying these novel risk factors, the study found that an increased number of years as a recreational runner, a lower average weekly running distance, and a slower average training running speed, were also predictive of developing GORRIs.

Knowledge of these novel factors, together with training variables, means these risk factors can be targeted to develop and implement injury prevention, treatment, and rehabilitation interventions in runners. This is important, because patients with a history of chronic disease will benefit greatly from the regular physical activity, including running.  The authors conclude that risk factors predictive of GORRIs are multifaceted and they suggest that a comprehensive medical assessment to identify chronic diseases and allergies should be considered as part of the clinical assessment of a runner presenting with a GORRI. The findings of these studies form the basis for future research to determine cause–effect in predictive risk factors of GORRIs in ultramarathon road and trail runners.

References:

Chronic Disease, Allergies, and Increased Years of Running Are Risk Factors Predicting Gradual Onset Running-Related Injuries in Ultramarathon Runners—SAFER XIX Study in 29 585 Race Entrants. Patience Mokwena, Martin Schwellnus, Audrey Jansen van Rensburg, Dimakatso Ramagole, Pieter Boer, Esme Jordaan. Clin J Sport Med 2021;00:1–8

Independent Risk Factors Predicting Gradual Onset Injury in 2824 Trail Running Race Entrants: SAFER XVIII Study. Carel Viljoen, Nicola Sewry, Martin Schwellnus, Dina Janse van Rensburg, Sonja Swanevelder, Esme Jordaan. Wilderness and Environmental Medicine, accepted April 2021, article in press.