The lack of standard concepts in research is perhaps the most significant difficulty in the comparison of results between studies. In the running injury field, many researchers have noted the problem of how to define a running-related injury.[2-4] Some investigators have suggested the need for a standardised definition of running-related injury.[2, 5-7] However, a consensus has not yet been reached; thus, researchers have used different definitions in their studies.[3, 8, 9]
Currently, the rates of prevalence and incidence of running injuries vary between 19% and 92%, depending on the injury definition adopted in the study. This means that the lack of standardisation of injury definitions may affect study results.[2, 3, 5, 9-15] For instance, Bovens, et al.  used a broad definition of running-related injury as “any physical complaint developed in relation with running activities and causing restriction in running distance, speed, duration or frequency”; they found an injury incidence of 84.9%. On the other hand, Blair, et al.  adopted a more stringent definition of running-related injury as “an injury that causes the runners to stop running for at least seven days”; they found a lower injury incidence of 24%. The higher rate of injury found in the first study may be due to the lack of a specific period of interruption or time off from running in the definition used, in contrast to the definition used in the second study, which clearly specifies the period of interruption.
Thus, the lack of a standard definition of running-related injury hinders comparisons between studies. Sports such as cricket, tennis, rugby and soccer have their consensus definition of injury.[19-22] The existence of these consensus provided uniformity to injury surveillance studies in these sports. A consensus definition of running-related injury will contribute to eliminate the wide variations observed in studies of running injuries as well as the implementation of effective prevention programs in the future.[2-4, 23] Therefore, the aim of this study is to reach a consensus definition of running-related injury through a modified Delphi approach.
Thirty-eight experts from nine different countries agreed to participate in this modified Delphi study. An analysis of their profiles shows that they are mostly experienced researchers with large expertise with running injury topic. The mean of articles published for each participant was approximately 70 articles and average H-index was 12.7. These data shows that the participants included are most influential researches of running injury field and are familiarised with the lack of a standardised definition of running-related injury. Thus, we believe that the participants included have the appropriated background to contribute to the development of this consensus.
Regarding to the structure of the consensus definition of running-related injury, our consensus is similar to other consensus definitions of...