Running Mechanics After Training on Sand in Runners With Pronated Feet: A Randomized Controlled Trial

Pronation in the foot is a normal rolling movement occurring at the subtalar joint during running. The human foot, as the primary interface with our environment, presents morphological and postural changes following prolonged running. This study aims to identify running mechanics while training on the sand in runners with pronated feet. 

Thirty runners with pronated feet were in the control group, and 30 runners with pronated feet were in the experimental group. An experimental group conducted an 8-week corrective exercise program, while a control group did not exercise. A force plate was included to collect ground reaction forces in the walkway. An analysis of variance (ANOVA) with repeated measures test was conducted to identify the presence of an interaction between the within-and between-subject factors on the dependent variables. The significance level was set at P<0.05.

The experimental group displayed lower first peak vertical ground reaction force (P=0.026), peak mediolateral ground reaction force (P=0.000), anterior-posterior impulse (P=0.032), loading rate (P=0.004) and a larger last peak vertical ground reaction force (P=0.000) during training on the sand. Irrespective of the group under consideration, a lower first peak mediolateral ground reaction force (P=0.000), peak positive free moment amplitude (P=0.001), and a larger last peak mediolateral ground reaction force (P=0.003) observed in the post-test compared to the pre-test. 

We suggest that training on sand may be a suitable intervention to change running mechanics in male runners with pronated feet.