The reliability of a smartphone application in measuring the foot structure of cyclists during sitting and standing

Previous studies have focussed on the relation between foot structure and function, revealing that 3D scanning is the measurement tool with higher precision and accuracy. However, to date only non-studies have investigated the test-retest reliability and potential of a smartphone 3D application for measuring foot morphology. The purpose of the present study was to assess the intra-rater reliability of the Avatar3D application in analysing the foot structure of cyclists. Thirty-five female road cyclists assessed her own foot through the Avatar3D application on two occasions separated by 10minutes. Instep girth, foot length, ball girth, and ball width were registered in sitting and standing positions during the test and retest. The reliability of the measurements was evaluated using intraclass correlation coefficient (ICC), coefficient of variation (CV's) and Bland-Altman plots. All dependent variables showed ICC range values from moderate to very high with low CV's (<6%), evidencing no significant changes in any variable. This thesis was reinforced by Bland-Altman plots and one sample t-tests (p > 0.05). The Avatar3D application is a reliable and easy-to-use tool for assessing the foot structure in female cyclists in sitting and standing positions.