_Applied_  
_sciences_  
_Article_  
**Test-Retest Reliability of Sole Morphology Measurements**  
**Using a Novel Single-Image-Based Pin-Array Impression**  
**Reconstruction Method**  
**[PERSON] 1,\({}^{\dagger}\), [PERSON] 2,3,\({}^{\dagger}\), [PERSON] 1, [PERSON] 1,4, [PERSON] 5, [PERSON] 1\({}^{\copyright}\) and [PERSON] 1,6,* \begin{tabular}{l l} \({}^{1}\) & Department of Biomedical Engineering, National Taiwan University, Taipei 106127, Taiwan; \\ [EMAIL_ADDRESS] (T.-Y.C.); [EMAIL_ADDRESS] (L.-W.H.); [EMAIL_ADDRESS] (W.-C.L.); \\ [EMAIL_ADDRESS] (H.-L.L.) \\ \({}^{2}\) & Department of Orthopedics, School of Medicine, China Medical University, Taichung 40433, Taiwan; \\ d43069 mail.com.tw \\ \({}^{3}\) & Department of Orthopedics, China Medical University Hospital, Taichung 40433, Taiwan \\ \({}^{4}\) & Department of Orthopaedic Surgery, Chang-Gung Memorial Hospital, Taipei 105406, Taiwan \\ \({}^{5}\) & Department of Mechanical Engineering, National United University, Miaoli 36063, Taiwan; [EMAIL_ADDRESS] \\ \({}^{6}\) & Department of Orthopaedic Surgery, School of Medicine, National Taiwan University, Taipei 100233, Taiwan \\ \({}^{\star}\) & Correspondence: [EMAIL_ADDRESS]; Tel./-Fax: +886-2-23562095 \\ \({}^{\dagger}\) & These authors contributed equally to this work. \\ \end{tabular}   
**Featured Application: A novel method for three-dimensional sole morphological measurements**  
**gives high intra-rater, inter-rater, and inter-session reliability regardless of the rater's experience or time of measurement, and will be useful for foot assessment and subsequent applications, such as design and manufacture of customized orthoses or shoes. **  
**Abstract: Background: Assessment of the sole morphology provides a clinically useful measure of the foot condition, but existing methods are mostly limited to two-dimensional or non-weight-bearing conditions. The current study aimed to assess the reliability of a novel method called Single-Image-Based Pin-Array Impression Reconstruction Method (SIBPAIR) implemented on a commercial foot assessment system, and the intra-rater, inter-rater and inter-session reliability of the SIBPAIR-based protocol for three-dimensional sole morphological measurements. Methods: The reliability of the SIBPAIR method, and the intra-rater, inter-rater, and inter-session reliability of the SIBPAIR-based protocol in measuring morphological parameters of the sole were assessed by repeated measurements of fifteen young healthy adults by two male physical therapists, in terms of intra-class correlation coefficients (ICC) and standard error of measurement (SEM). Results and Conclusions: The SIBPAIR method was found to have very high reliability with very small SEM values, and the SIBPAIR-based protocol also showed very high intra-rater, inter-rater, and inter-session reliability with small SEM. These results indicate that accurate and reliable measurements could be obtained by following the protocol regardless of the rater's experience or time of measurement. This will be useful for foot assessment and subsequent applications, such as design and manufacture of customized orthoses or shoes. **  
repeatability; foot morphology; foot scan; arch height; arch index  
**Copyright:** **copy 2021 by the authors. Licensee MDP, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ([[https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/)]([https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/))). **  
**1. Introduction**  
The foot is one of the most complex anatomical structures in the human body, playing an important role in the normal function of the lower extremities [1]. The foot adapts to various terrains, and provides support and mobility necessary for standing and walking while bearing the body weight.