Effect of exercise therapy on eversion / inversion angle in female runners : A pilot study

Background: Running has many health benefits and has therefore become a sport with an expanded popularity worldwide. With it comes an increased incidence of overuse injuries, and there is a constant debate whether the shoes a runner uses should be as supportive as possible or minimalistic in order to facilitate a more natural running pattern. Many running retail outlets use video analysis to find out whether the runner has excessive rearfoot eversion (if they overpronate) or not and prescribe running shoes accordingly. Purpose: The purpose of the present study was to investigate the effect of an exercise program on pronation/rearfoot eversion in female recreational runners and compare the results to running with a shoe with support under the midsole, a stability shoe. Method: Eight participants were recruited, and they were all recreational female endurance runners. On test day 1 a maximum voluntary isometric contraction (MVIC) of the ankle invertors was recorded. After that, the rearfoot inversion/ eversion angle was measured whilst running on a treadmill both in neutral and in stability shoes. The participants were divided in two groups using the every other method, and the intervention group (5 participants) went home with an exercise program to carry out over 6-8 weeks, and the control group (3 participants) did not. On test day 2 the same procedure followed. Due to the small sample size the current study is categorised as a pilot study. Results: There was no significant difference (p>0.05) in maximum voluntary isometric contraction between the two test days, in both groups, and also no significant difference (p>0.05) in rearfoot eversion in either of the groups and not when comparing the different types of shoes. Looking at individual results in the study group however there is an indication that rearfoot eversion decreased for more participants than did not, and it would therefore be of interest to look at this topic on a larger group. Conclusion: The results showed no significant difference in rearfoot eversion/ inversion after exercise therapy, however after analysing individual results it would be of interest to see this pilot study on a larger group.