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.
Desai P, Jungmalm J, Börjesson M, Zello GA, Karlsson J, Grau S. J Orthop Sports Phys Ther. 2020 Dec 25;1-23.
Recreational half marathon runners that reported any previous running-related injury were twice as likely to develop another lower extremity running-related injury within a year of running a half marathon, regardless of age, body mass index, and weekly mileage.
Running-related injuries (RRI’s) are extremely common among the running community, and as such, many researchers have investigated injury risk factors. While retrospective studies have linked some past injury, training, and demographic traits to RRI’s, it is unclear if these same risks would be present when assessing runners over time. Prospective evaluations would allow clinicians to better assess injury incidence rates and risk factors to improve clinical care.
The authors of this study aimed to determine the total number of new RRI out of the study sample (cumulative RRI incidence proportions), injury locations, and risk factors associated with RRI development among recreational half-marathon runners over time.
The authors followed 224 healthy male and female runners who competed in regional half-marathons for one year after race participation. The study team assessed the runners at baseline for their age, sex, body mass index, previous RRI history 6 or more months before participation, years of running experience, and average weekly mileage. The runners then reported any pain during running every week. A study team physician assessed any runner who reported pain to determine the occurrence of an RRI. The authors defined an RRI as an injury to the lower extremity or back that limited running or required an evaluation by a healthcare provider. Runners who stopped reporting to the study or restricted their running training were excluded from analyses.
Overall, 75 runners (46% cumulative incidence proportion) developed RRI’s over the year. Most injuries were classified as knee and Achilles tendon or calf injuries. The authors found that runners who reported previous RRI’s were twice as likely to sustain a new RRI during the study than runners without injury history. No other training or demographic factors related to RRI development.
Overall, this large-scale prospective study identified RRI history as a key risk factor for developing a new RRI. Past retrospective studies have also identified previous injury to be predictive of future injury. However, this study is the first to show this relationship over time in a recreational running population. The most-reported injury types were localized to the knee and calf, which aligns with previously reported retrospective studies. Interestingly, the authors did not identify training factors as risk factors for RRI’s. However, this may be because the researchers assessed training behaviors at baseline alone, and all participants had just completed a half marathon race, which may have narrowed the range of training behaviors. Similarly, body mass index was unrelated to heightened injury risk, but this may be because very few runners were overweight. These training and demographics findings may not necessarily transfer to other recreational running groups. It is also important to note that the authors opted to relate baseline measures to RRI’s over time. With the advent of more advanced monitoring tools, such as wearable tracking devices, there is the potential to expand upon this study to evaluate RRI risk factors over time. For example, examining how training load over the prior month related to the onset of RRI. This study importantly laid the foundation for future studies and lent further insight into the link between past and future injury.
Clinicians should evaluate and monitor runners with a prior injury more closely to determine if other predisposing factors led to their previous injury. Furthermore, clinicians should check if an athlete is fully rehabilitated before returning to activity. The authors also acknowledged the need for clinicians to consider other factors that may relate to RRIs such as training intensity, running form, nutrition, and general well-being.
Questions for Discussion
What factors have you noted among runners that have gone on to develop running-related injuries in your clinical practice?
Written by: Alexandra F. DeJong
Reviewed by: Jeffrey Driban