# Effects of 10 KM run on foot morphology and bilateral symmetry in male recreational runners

## TL;DR

A 10 KM run causes small changes in foot size and arch height in male recreational runners, suggesting the need for shoes with arch support.

## Contribution

This study quantifies foot morphology and arch changes after a 10 KM run using 3D scanning in male recreational runners.

## Key findings

- Foot length increased and ball girth decreased slightly after a 10 KM run.
- Foot arch height significantly decreased while arch stiffness increased.
- Bilateral symmetry changes were observed in navicular height and arch height ratio.

## Abstract

Foot morphology and arch integrity do not remain constant during a running bout. Previous studies have reported inconsistent changes in foot sizes and arch parameters and this discrepancy may be related to the variation in their test duration, e.g., 15-min treadmill run vs. 30 KM trial. Hence, this study sought to evaluate the change in foot morphology, arch integrity and bilateral symmetry after a 10 KM run among 19 male recreational runners. Before and after the run, a portable foot scanner was used to capture the 3-dimensional foot images and measure foot dimensions in both weight-bearing and non-weight-bearing conditions. Foot arch integrity was quantified by arch height ratio, arch height index, and arch stiffness index (ASI). Bilateral symmetry was evaluated by calculating the symmetry index. Increased foot length (p = 0.007;
ηp2
= 0.18) and decreased ball girth (p = 0.038;
ηp2
= 0.11) were demonstrated following the run with absolute differences of less than 2 mm. Navicular height, dorsum height, arch height ratio and arch height index significantly decreased after the run (p < 0.001;
ηp2
≥0.30) whereas ASI increased (p < 0.001,
ηp2
= 0.33) and navicular height drop reduced (p < 0.001,
ηp2
= 0.37). Significances of symmetry index were only demonstrated for navicular height (p = 0.019, effect size = 0.37) and arch height ratio (p = 0.019, effect size = 0.42). A few changes in foot morphology were detected but a reduction in foot arch height was demonstrated, which may give shoe manufacturers insights into shoe design. Male recreational runners were recommended to choose shoes with arch support for maintaining foot arch function during a 10 KM run.