Barefoot Running Is Associated With Reduced Gastrointestinal Distress Symptoms In Males

Endurance runners experience high rates of gastrointestinal (GI) distress (e.g., nausea, vomiting, diarrhea, and cramping). Running and the high-impact forces that accompany “foot striking”, particularly when landing on the heel, is postulated to be a causative factor in the occurrence of GI distress and its related symptoms. Running barefoot (BF), however, forces runners to land on their forefoot, thus reducing ground reaction forces and potentially GI distress. To date, however, no such research has looked at the relationship between these factors. PURPOSE: The purpose of this study, therefore, is to determine the prevalence of symptoms related to GI distress in endurance runners as a function of their running kinematics as determined by whether runners run BF (i.e., low impact-fore/mid-foot strikers) or shod (SH; i.e., high impact-heel strikers). METHODS: A brief, 12-item, anonymous, online survey asking about the occurrences of GI distress symptoms (never=1, sometimes=2, occasionally=3, frequently=4) during running was completed by 157 respondents (n=51 BF [33 male, 17 female], n=106 SH [37 male, 69 female]). Potential respondents had to engage in running distances greater than 3 km at a time for greater than or equal to (≥) 4 d/wk. To qualify as BF, respondents had to answer “yes” to running >50% of the time in no or minimalist shoe wear. RESULTS: There were no significant differences (p>0.05) in age (45.8 ± 9.8 vs. 44.6 ± 10.0 yrs), weight (71.3 ± 14.3 vs. 67.6 ± 14.2 kg), or days spent running (4.5 ± 0.8 vs. 4.7 ± 0.9 d/wk) between BF and SH, respectively. There was, however, a statistically significant difference (p=0.029) in self-reported GI distress scores between BF and SH runners, with BF runners reporting lower GI distress scores (4.5 ± 4.7 vs. 7.8 ± 6.6, respectively). Two-way ANOVA revealed that this difference was accounted for entirely by the male BF runners (p=0.002). CONCLUSIONS: Barefoot running was associated with lower self-reported GI distress scores in male runners only. More research is needed to confirm and discern the nature of this association.