The longer exposure of the musculoskeletal system to running may explain this association. Any runner executes around 50 to 70 strides per minute and each ground contact generates loads ranging from 3 to 8 times the total body weight through the lower limbs (Macera et al 1989). The application of this load for long periods of time accumulated over years of running training could explain the association between running experience and presence of musculoskeletal pain in our study cohort. We also observed a statistically significant difference in the weekly running distance between respondents with and without pain, which is consistent with previous studies (Fredericson and Misra 2007, Macera

et al 1989, Walter et al 1989). However,

the distribution of the data suggests that it is not the average weekly Everolimus cell line running distance that is important, but whether the distance is above a certain threshold, which is also consistent with other studies (Fredericson and Misra 2007, Macera et al 1989). We did not observe a significant difference in the number of training sessions per week between respondents with and without pain, which is consistent with the findings of van Middelkoop and colleagues (2008). We selleckchem are aware of some limitations of our study and we suggest that our findings should be interpreted cautiously. First, although we recruited a representative sample, our analysis is purely cross-sectional and no causation should be interpreted from our study. We suggest that more prospective, longitudinal studies should be performed in the future. Second, due to feasibility issues, we collected all information from the respondents through self-report questionnaires, with no clinical assessment Astemizole being performed. We understand that the athletes could interpret the presence of pain in different ways, and a clinical assessment would supplement

the data collected by the questionnaires. Nevertheless we do believe that the data and our subsequent analyses do give a reasonable and useful indication of the current presence of running-related musculoskeletal pain in recreational athletes who are competing in a running event. This study presents important information on the issue of sports participation despite the presence of pain. To our knowledge, there is no study on the effects of early identification of overuse injuries and possible physiotherapy interventions for this problem. Therefore studies on this topic are needed urgently. We also suggest that studies should be performed to investigate the relationship between the presence of pain and actual disability (or performance) in this population. Finally, qualitative studies would clarify why amateur runners commonly decide to participate in competitions despite their pain. The prevalence of recreational runners competing in a race with musculoskeletal pain is high.