Footstrike pattern at the 10 km and 39 km points of the Singapore marathon in recreational runners

The prevalence of rearfoot striking is similar to 60% in elite marathoners, but similar to 90% in North American and European recreational marathoners. Recent data indicate that this prevalence is similar to 70% in Asian recreational marathoners. How this prevalence changes throughout the course of a marathon remains undocumented. We filmed 350 runners at the 10 km and 39 km marks of the Singapore marathon (similar to 71% Asian field), and classified footstrike patterns in 347 and 327 runners at these locations. The prevalence of rearfoot, midfoot, forefoot, and asymmetric patterns was 65%, 21%, 33%, and 11% at 10 km, which differed significantly from the corresponding 77%, 15%, 1%, and 8% at 39 km (p < 0.01). The prevalence of non-rearfoot strikers at both filming locations was greater than reported in the literature for North American recreational marathoners (p < 0.01), but lower than reported for non-Asian elite marathoners (p <= 0.02). The 12% increase in rearfoot strikers at the later mark of the marathon in our Asian cohort of recreational runners was greater than the 5% increase reported for the North American-based cohort (p < 0.01), but comparable to the one reported for non-Asian elite runners (p = 0.97). Our findings confirm previous conclusions that running research should consider and report ethnicity alongside performance standards given that both can (in part) explain biomechanical differences in running gait. Noteworthy is that numerous factors can influence marathon performance and fatigue that here remained unaccounted for, including age, sex, course profile, footwear, and environmental conditions.