Research project Running-related injuries among recreational runners

This research project addresses one of the most popular forms of physical activity in Sweden, namely running. As physical activity, such as running, prevents many of the lifestyle-based diseases that are common in the western world, it is important from a public health perspective to minimize the risks of physical activity so that more people can continue to be active. However, runners are vulnerable to various types of injuries, and the most common reason to quit running is an overuse injury. The mechanisms behind overuse injuries are not clearly described in the literature, and the purpose of the project is therefore to identify risk factors that influence the development of running-related overuse injuries in recreational running.

The project was granted ethical approval by the Regional ethics review board in Gothenburg (file number 712-15) in the autumn of 2015 and data collection started in spring 2016 at Center for health and performance (CHP), University of Gothenburg's test center. With assistance from Gothenburg half marathon we were able to include 227 recreational runners (89 women, 138 men). All runners underwent a comprehensive physical examination regarding mobility, running style and strength and were then asked to register their training in a certain log for the upcoming 52 weeks. Data collection lasted for two years, as it took approximately one year to finish the initial physical examination for all participants.

The aim of the project is to increase knowledge about various risk factors that affect the development of running-related injuries in recreational runners. Among other things, the project has contributed to an increased understanding of the type of runners who have an increased risk of sustaining running-related injuries.

The following is a summary of the scientific articles that have been published within the project.

The study protocol (Jungmalm et al., 2018) describes the methods we have used in the project in detail. Moreover, we also discuss the importance of collecting training-specific data (such as distance, intensity, frequency) and data that represents runners' capacity (how much a person can train before injury occurs in a structure) as well as data on factors affecting load-distribution (eg running speed, type of shoes and surface).

The publication in BJSM (Jungmalm, Bertelsen & Nielsen, 2020) describes how cumulative injury incidence proportion changes depending on whether it is calculated with or without censoring. The more runners who are censored during the study period, the greater the differences. Four prospective cohort studies that together studied 2,798 runners (56.8% women) were included.

Data from Desai et al. (2020) shows that the most injured structure of recreational runners was the knee and the area around the Achilles tendon / calf muscles. The likelihood of suffering an injury was greater for runners who had previously been injured. Both for the previously injured runners and for those who had never had an injury, the likelihood of suffering a new injury with increased running distance per week increased.

Results from Jungmalm et al. (2020) shows that runners with a relatively late timing of maximum ankle eversion suffered 20.7% (95% CI = 1.3; 40.0) more injuries compared with runners with a later timing of the maximum ankle eversion. In addition, the study showed that runners with weak hip abductors in relation to hip adductors suffered 17.3% (95% CI = 0.8; 33.7) more injuries compared with the reference group.

• Recreational Runners With a History of Injury Twice as Likely to Sustain a Running-Related Injury Than Runners With No History of Injury: A One-Year Prospective Cohort Study

• Study protocol of a 52-week Prospective Running INjury study in Gothenburg (SPRING)
• What proportion of athletes sustained an injury during a prospective study? Censored observations matter

• Associations between biomechanical and clinical/anthropometrical factors and running-related injuries among recreational runners: a 52-week prospective cohort study