Document Type

Article

Publication Date

12-2026

Department

Department of Psychology and Human Factors; Health Research Institute; Department of Kinesiology and Integrative Physiology

Abstract

Background: Adherence to exercise interventions is often suboptimal, despite numerous studies documenting barriers and facilitators. Usability may be a critical yet underexplored determinant of adherence. This study aimed to develop and assess the psychometric properties of the Intervention Usability Scale for Exercise (IUSE). Methods: Item generation and content validation involved cognitive interviews and feedback from eight exercise intervention stakeholders and ten target users from the general public. Subsequently, 526 target users from University, Qualtrics and Prolific participant panels assessed exercise programs through an online survey. Dimensionality was assessed using Principal Component Analysis (PCA), Exploratory Factor Analysis (EFA), and bifactor models. Item reduction was conducted through Item Response Theory (IRT) graded response models, assessing discriminability, item information levels/patterns and differential item functioning. Test-retest reliability was assessed using Pearson’s r. Subsequently, short vs. original scale versions were compared. Finally, evidence of criterion, convergent, and discriminant validity was assessed. Results: Thirty-six items were initially included, with 16 removed due to low test-retest reliability and factor loadings (r < 0.50). A 3-factor structure emerged from EFA, PCA, and bifactor models: Value, Ease, and Social. Iterative IRT evaluation led to 12 item removals, resulting in 8 final items across three subscales. Validity analyses indicated good convergent (e.g., r = 0.79 with Intervention Appropriateness Measure, r = 0.65 with Intervention Usability Scale), criterion (e.g., r = 0.71 with Net Promoter Score and 0.75 with intention measures), and discriminant validity (r = 0.42 with External Motivation), along with satisfactory internal consistency (Cronbach's alpha: 0.79-0.84). Conclusions: The IUSE scale demonstrated promising psychometric properties. Application of the scale with collection of actual uptake/adherence data is needed to assess predictive validity.

Publisher's Statement

© 2026 The Authors. Published by Elsevier Inc. on behalf of Human Factors and Ergonomics Society. Publisher’s version of record: https://doi.org/10.1016/j.hfh.2026.100142

Publication Title

Human Factors in Healthcare

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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