Foot Volume Change during Long Distance Running in Healthy Adults

Abstract

Background and purpose: Healthy adults frequently engage in running as a means of cardiovascular exercise. Larger running shoes are often chosen based on common beliefs that feet swell during running, yet many continue to encounter foot injuries, such as blisters, as a result of this activity. Previous research has analyzed the changes in foot volume during short bouts of activity. However, there has been limited research on the effect of long distance running on foot volume, which is where many of these injuries are seen. The purpose of this study was to examine the effects of long distance running, defined as 10 kilometers (10K), on foot volume in healthy adults. Subjects: Twenty-eight healthy subjects (18 females and 10 males) participated in the study. Methods: Upon arrival, participation information (gender, running status) and baseline foot measurements (shoe size, foot volume) were obtained. After a 5 minute warm up, participants completed the 10K run at a self selected speed. Immediately following the completion of the run, comparison measurements were once again taken. Results: No difference was found between pre and post volumetric measurements (p=0.897). There was a significant interaction in pre and post volumes between individuals classified as runners and non-runners (p=0.014) but simple main effects were inconclusive. A significant difference in the pre-run (p=0.006) and post-run (0.001) volumes of the two groups was observed, but there was no significant change in the foot volume of the runners (p=0.100) or the non-runners (p=0.065). No relationship existed between the difference in shoe to measured foot size and the foot volume change (p=0.436). There was no significance between gender and volume change (p=0.868). A statistically significant relationship was found to occur between outside temperature and foot volume change (r=0.419). Discussion: Running a 10K did not result in a significant change in foot volume, even when subjects were divided by running status or gender. Since previous research has seen a trend towards foot volume increasing following short runs and decreasing following a marathon, a 10K run may be an equilibrium point between when a foot initially swells and when it shrinks smaller than its initial volume due to extraneous variables associated with a longer run (i.e. dehydration). Change in foot volume was related to the outside temperature, which may also be related to increased dehydration during runs in hotter temperatures. Conclusion: This study found temperature as the only variable affecting foot volume following a 10 K run, with higher temperatures resulting in a greater change in foot volume. Due to the existence of several design flaws, the results should be interpreted with caution. Future studies should control for more of the confounding variables, by completing the run indoors and increasing the number of participants in order to…