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Abstract
Objectives The purpose of this study was to describe injury patterns and healthcare utilisation of marathon runners.
Methods This was a previously reported 16-week prospective observational study of runners training for the New York City Marathon. Runners completed a baseline survey including demographics, running experience and marathon goal. Injury surveys were collected every 4 weeks during training, as well as 1 week before and 1 week after the race. Injury details collected included anatomic location, diagnosis, onset, and treatment received.
Results A total of 1049 runners were enrolled. Injuries were reported by 398 (38.4%) during training and 128 (14.1%) during the marathon. The overall prevalence of injury was 447/1049 (42.6%). Foot, knee and hip injuries were most common during training, whereas knee, thigh and foot injuries were most common during the race. The most frequent tissue type affected was the category of muscle, tendon/fascia and bursa. The prevalence of overuse injuries increased, while acute injuries remained constant throughout training. Hamstring injuries had the highest prevalence of diagnosis with 38/564 injuries (6.7%). Of the 447 runners who reported an injury, 224 (50.1%) received medical care. Physical therapy was the most common medical care received with 115/1037 (11.1%) runners during training and 44/907 (4.9%) postrace.
Conclusion Runners training and participating in a marathon commonly experience injuries, especially of the foot and knee, which often are overuse soft tissue injuries. Half of the injured runners sought out medical care for their injury. Understanding the patterns of injuries affecting marathon runners could help guide future injury prevention efforts.
- injuries
- training
- marathon
- running
- injury
Data availability statement
Data are available upon reasonable request.
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
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WHAT IS ALREADY KNOWN ON THIS TOPIC
Training for and participating in a half or full marathon have been associated with a high risk of running-related injury (RRI) with a prevalence of 29%–44% during training.
RRIs can result in training time lost, failure to complete a race and a financial burden on the athlete and medical system.
WHAT THIS STUDY ADDS
Among runners who were injured while training for and participating in a marathon, the most affected tissue type was soft tissue (muscle, tendon/fascia and bursa), and the most common anatomic locations of injury were the foot and knee.
While the most common medical service used by marathon runners for their injuries was physical therapy, 1 in 23 had an MRI before or after the race. For a large marathon like the New York City Marathon, this equates to over 2000 MRIs for injuries associated with training or participating in the marathon.
Overall incidence and pattern of injury were consistent in age groups.
HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY
Understanding the types of injuries affecting marathon runners could help guide future injury prevention programmes.
Understanding the healthcare utilisation among marathon runners throughout training and racing can help clinicians better prepare for, evaluate and treat these injuries.
Introduction
Running is one of the most common forms of exercise worldwide. Running race participation has increased by 57% over the past decade, with approximately 1.1 million people finishing a marathon worldwide each year.1 2 Running-related injuries (RRIs) are common among recreational runners with an incidence ranging from 4.0 to 6.3/1000 training hours in varied populations of runners.3–5 RRIs are often presumed to be multifactorial as risk factors are broad and include a history of RRI, inexperience, strength deficits, training errors, biomechanics and orthotics use.6–10 Training for and participating in a half or full marathon have also been shown to be associated with an increased risk of RRI.6 8 In the lead-up to a marathon or half marathon, the prevalence of RRI ranges between 29.2% and 43.5%.11 RRIs can result in training time lost, failure to complete a race and a financial burden on the athlete and medical system.12 RRIs have been shown to prevent nearly 10% of runners from reaching the starting line of their goal marathon and account for 35% of prerace dropouts.13 Healthcare utilisation associated with RRIs can be a financial burden on athletes and the medical system, despite a relatively low amount of time loss from work.14
Understanding why runners get injured is essential when creating injury prevention programmes. To date, few interventions have resulted in a measurable decrease in injuries among runners.15–18 Foundational to understanding why runners get injured is understanding how runners get injured. There are little data available for marathon runners throughout training and racing to determine when runners are more likely to experience injuries, what those injuries are (eg, anatomic location and tissue type), the effect of age on injury patterns and runners’ healthcare utilisation for these injuries.19
A more robust understanding of the patterns, types and timing of injuries would allow researchers and sports medicine professionals to better understand why marathon runners get injured. This could lead to more precise identification of modifiable risk factors, which could in turn lead to the development of methods for effective injury prevention for runners. The purpose of this study is to describe the distribution and types of injuries experienced by a cohort of marathon runners and measure healthcare utilisation for these injuries, which can add a financial burden to runners and healthcare systems.
Methods
This was a secondary analysis of a previously reported 16-week observational study of runners training for the 2019 New York City Marathon.20 Eligibility criteria included marathon registrants, age 18 years and older, English-speaking and without a current injury. A study recruitment email was sent by New York Road Runners to all registrants 20 weeks before the marathon.
Data collection
Data were collected and managed using Research Electronic Data Capture (REDCap), which is a secure web platform for online databases and surveys that is supported by the Weill Cornell Medicine Clinical and Translational Science Center and subsidised by National Institutes of Health (NIH) grant UL1 TR0002384 from the National Center for Advancing Translational Sciences of the NIH. The recruitment email included a link to an electronic consent form and a baseline survey (online supplemental appendix A), which asked about age, sex, race, ethnicity, height, weight, marathon goal, current running patterns (average runs/week and distance/week in the past month), running race experience (number of completed half and full marathon and fastest finishing times) and other forms of exercise.
Supplemental material
The 16 weeks before the marathon were divided into four training quarters (TQ), numbered TQ1–TQ4. A survey was administered at the end of each TQ to inquire if the runner was still planning to participate in the marathon and whether the runner had sustained an injury (online supplemental appendix B). For those who were no longer planning to participate in the marathon, runners were asked to provide a primary reason. One week after the marathon, a final survey (online supplemental appendix C) was administered that asked if the runner started the marathon, finished the marathon (if not, the primary reason why not), finishing time and if their finishing time was affected by an injury.
Supplemental material
Supplemental material
Runners who reported an injury were also asked how the injury affected training or the marathon itself, as well as the location of the injury, any specific diagnosis (if known) and what medical care had been received for the injury (if any). Injuries during training were defined as those that limited training frequency, distance or pace. Pain while training (without an associated impact on training) was not considered an injury for this study. An injury associated with the race was recorded if it was the primary reason for a finishing time being slower than the runner’s goal or if the runner received medical care for it in the week after the marathon.
Injured runners were asked to select the anatomic location primarily affected: low back, hip, thigh, knee, leg, ankle, foot or others. Runners then selected a diagnosis to the best of their knowledge (table 1). Diagnoses were classified by tissue type by the investigators as one of the following: (1) muscle, tendon/fascia, bursa, (2) joint, (3) bone or (4) nerve. For the onset of injury, runners selected one of the following: (1) ‘acute injury, such as a twisted ankle’; (2) ‘rapid onset of an overuse injury, such as a pulled muscle’; and (3) ‘gradual onset of an overuse injury, such as shin splints, iliotibial (IT) band syndrome or plantar fasciitis’. All questions also included ‘other’ and ‘don’t know’ as options. At any point, if a runner experienced more than one injury, the runner was asked to report only the most severe injury.
Running injury diagnoses and tissue type affected by anatomic location
Statistical analysis
Runners were included in the current analysis if they completed at least one injury survey (TQ1–TQ4 or postrace). Descriptive statistics were used to analyse baseline characteristics, which included means and SD for normally distributed data and medians and IQRs for non-normally distributed data. χ2 tests were used to compare the prevalence of injury between the TQs, as well as tissue types by age group. For runners who had previously reported that they intended to participate in the marathon but reported in the postrace survey that they did not start the marathon due to injury, the injuries were classified as ‘prerace’ and were included in TQ4. For runners who reported multiple injuries, a subsequent report of an injury of the same anatomic location was considered the same injury. For runners who reported an injury of the same anatomic location on more than one survey, the final diagnosis reported on the last survey was used.
Results
A total of 1082 runners enrolled and participated in the study.20 1049 runners met the inclusion criteria for the current analysis (the remainder opted out or became injured prior to the start of the observation period and were excluded). Table 2 shows summaries of their demographics and running experiences. During the study period, 142 runners stopped training because of reasons unrelated to injury or were lost to follow-up. Given that the 1049 runners were sent 5 surveys each, a total of 5245 surveys were distributed, among which 4792 (91.4%) were completed. There were 907 runners (86.5% of runners enrolled) that started the marathon and 896 that completed it (85.4% of runners, 98.8% among those who started). The mean time to finish the marathon was 4 hours and 26 min (SD 60 min).
Demographics and baseline running information
Specific to the runners included in this analysis, injuries were reported by 398/1037 (38.4%) during training. Of the 907 runners who participated in the marathon, 128 (14.1%) reported an injury that either affected their finishing time or required medical care after the race. The overall prevalence of injury during both training and the race was 42.6% (447/1049). The prevalence at each TQ and the overall incidence of injuries by anatomical location, tissue type and onset are shown in table 3. There was a statistically significant increase in injury prevalence from TQ1 to TQ4 (X2 p<0.001).
Injury prevalence and overall incidence by anatomic location, tissue type and onset
The specific diagnoses (as best understood and reported by the runner) are listed in table 4.
Diagnosis by location
The tissue type injured by age group is shown in table 5. Although the proportion of joint injuries was slightly higher among runners age ≥50 years (compared with the younger age groups), it was not statistically significant (X2 p=0.38).
Injury tissue type by age
There were 224 runners who reported receiving medical care for their injuries during training and after the marathon, equating to 21.4% of all runners (n=1049) and 50.1% of those reporting an injury (n=447). The specific healthcare utilisation during training and after the race is shown in table 6.
Healthcare utilisation
Discussion
In this large cohort of runners who we were prospectively following while training for and participating in the New York City Marathon, we showed a propensity during training for foot (93/1037, 9.0%), knee (87, 8.4%) and hip (73, 7.0%) injuries, whereas during the race, knee (26/907, 2.9%), thigh (25, 2.8%) and foot (23, 2.5%) injuries were the most reported. Injuries of the muscle, tendon/fascia and bursa category were the most frequent tissue type injured at each time point in this study. As expected, overuse injuries were more common than acute injuries with the prevalence of overuse injuries having steadily increased throughout training, while the prevalence of acute injuries remained more consistent. Gradual onset of an overuse injury was the most common form of symptom onset during each TQ as well as during the marathon. As for self-reported diagnoses, hamstring strain/tear had the highest incidence. The incidence of injury by age group was similar, but there was an increased incidence of joint injuries in older runners. Physical therapy was the most used form of medical treatment.
The predominance of knee and foot injuries has been reported in multiple studies of marathon runners.19 21–26 In terms of knee diagnoses, IT band syndrome and patellofemoral pain/chondromalacia patella were most common in our cohort of marathon runners, which is consistent with a literature review of the epidemiology and aetiology of injuries in marathon runners by Fredericson et al.27 As for diagnoses of the foot and ankle, our data support prior RRI evidence that Achilles tendinosis and plantar fasciitis are the most common injuries to those anatomic locations. Di Caprio et al observed 166 runners over 4 years and reported that the most common injuries were plantar fasciitis (31%) and Achilles tendinopathy (24%).28 The pattern of knee and foot injuries was also described by Lopes et al, in a systematic review of ultramarathon runners where the rates of patellofemoral pain and Achilles tendinopathy were higher than any other anatomic location.29 Additionally, a high rate of hamstring injuries among marathon runners was reported by Longo et al, who collected injury questionnaires from 700 runners of the 2019 Rome Marathon.30 Within our cohort, thigh injuries were the second most common race injury location, of which the majority (54%) were attributed to hamstring injuries.
The overall incidence of injury was consistent between age groups, as was the distribution of injuries by tissue type affected. The prevalence of lower extremity joint injury in the two older age groups (5.0% and 6.7%) in this study was less than the prevalence of knee osteoarthritis in the general population of 55–60-year-olds (almost 10%).31 32 Despite perceptions about the negative impact of running on knee health,33 several recent systematic reviews suggest no difference in rates of knee osteoarthritis, progression of knee arthritis symptoms, patient-reported outcomes or radiologic progression of knee osteoarthritis in populations of runners compared with non-runners.34 35 Further research is needed to determine the true effect of running on knee osteoarthritis.
The information presented here can help refine other analyses of risk factors for injury. Our previous analysis of training patterns associated with injury from this cohort of runners showed that rapid increases in training as measured by the acute to chronic workload ratio were associated with increased injuries.20 However, this analysis of training patterns did not differentiate acute versus overuse injuries or soft tissue versus bone/joint. If a larger cohort of runners can be similarly measured, by involving multiple marathons or multiple years, the training patterns associated with injury could be identified for specific injury onset patterns and tissue types. Additionally, a better understanding of the type and onset of injury may help inform future injury prevention programmes for runners by identifying potentially preventable injuries. Specifically, training modifications may prevent overuse injuries in general, whereas strength training interventions may prevent soft tissue (muscle, tendon/fascia, and bursa) injuries. This estimate of potentially preventable injuries is needed to accurately power future interventional studies.
More than half of the injured runners in our study (50.1%) reported receiving some form of medical care with the most common being physical therapy, which was similarly observed in a cohort of 1696 novice runners by Smits et al.14 Wayner et al also showed that the use of rehab services was the predominant form of medical utilisation when looking at bone stress injuries in cross-country runners (168 bone stress injuries generating 1764 athletic training services and 117 physician encounters).36 For the purpose of this study, seeking out physician services, physical therapy or other medical services was weighted equally whether that entailed one visit or several. While X-ray was the most used imaging modality, the use of MRI was notable. We found that 1 in 23 marathon runners get at least one MRI during training or in the week following a marathon. If this cohort was representative of all registrants of the 2019 New York City Marathon, which had 54 205 starters, this translates to over 2300 MRIs performed for injuries related to training for the marathon before accounting for those that were unable to start the race due to injury. This represents a significant use of healthcare resources and costs stemming from marathon running.37 Future directions may evaluate whether this cost is offset by any potential reduction in the financial burden of chronic disease that may be reduced from running. In addition, future directions may look into the injury patterns of the 49.9% of runners who did not seek medical care and how they compare with those who did seek medical care.
Strengths and limitations
This study included a large cohort of runners training for the same event, with frequent injury surveillance surveys and a high response rate. This robust dataset allows for a better understanding of the types of injuries experienced by marathon runners, the timing of when injuries occur and the medical care received. By using a self-reported survey, we captured injury data from runners who received care during the race as well as those who did not receive medical care until after the race. Given that an injury in this study was defined as having affected training or marathon participation, pain or dysfunction that does not limit training was not captured in this study. With an injury defined as having affected training or marathon participation, runners who elect to run through an injury/pain may go unreported. Diagnoses were self-reported and hence not extracted from medical records or recorded by clinicians directly. This may lead to misclassification of both the specific diagnoses and the tissue type. Our study participants may have a stronger bias towards seeking medical care, limiting the translation of our results to the overall collection of marathon runners. Further limitations include the large time frame of each TQ. Evaluation on a more frequent basis with smaller sections of the training time in between may help to further elicit when/how injuries occur relative to training.
Conclusion
This study analysed injury data from 1049 runners from a single marathon and demonstrated an overall injury prevalence of 43%. We found that knee (with 8.4% during training and 2.9% during race) and foot injuries (with 9.0% during training and 2.5% during race) were the most common conditions at all time points and increased as the training cycle progressed. Hamstring injuries were the most common diagnosis. Older runners have similar overall incidence of injury and distribution of affected tissue types. Half of the runners who reported an injury received medical care, predominantly physical therapy services.
Data availability statement
Data are available upon reasonable request.
Ethics statements
Patient consent for publication
Ethics approval
This study involves human participants and was approved by the Hospital Special Surgery Institutional Review Board on 5 March 2019 and renewed on 5 February 2020 (study ID 2019-0279). Participants gave informed consent to participate in the study before taking part.
Acknowledgments
The authors wish to thank New York Road Runners and Jessica Podell for making this study possible.
References
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Footnotes
Twitter @mcgrathtodd, @bretttoresdahl
Contributors TMM: study design, data analysis, manuscript preparation and guarantor. MAF: statistical analysis, data analysis and manuscript review. BGT: study design, data collection, data analysis and manuscript review.
Funding The study also used REDCap, which is supported by the Weill Cornell Medicine CTSC and subsidised by grant UL1 TR0002384 from the National Center for Advancing Translational Sciences of the NIH.
Competing interests None declared.
Patient and public involvement Patients and/or the public were involved in the design, or conduct, or reporting, or dissemination plans of this research. Refer to the Methods section for further details.
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.