The Concurrent Validity and Reliability of the Smartphone Measurement Application to Evaluate Iliotibial Band Tightness: A Cross-Sectional Study

Abstract

Purpose: In recent years, the medical use of smartphones has increased with the development of hardware. The study aims to evaluate the reliability and concurrent validity of iPhone® measurement application to measure ITB tightness. Methods: This was a cross-sectional study. Thirty athletes with ITB tightness (17 males, 13 females) between 20 and 45 years old were included and assessed in this study. The intraclass correlation coefficient (ICC) was used to evaluate the reliability of each smartphone measurement, and Bland–Altman analysis was used to examine measurement errors. The ITB tightness was measured with Ober test using a bubble inclinometer and iPhone® measurement application and evaluated by two experienced physiotherapists. The researchers carried out three measurements for both extremities, using both the bubble inclinometer and the iPhone® measurement application. Measurement values were recorded by a third physiotherapist. Results: The iPhone® measurement application has strong inter-rater (ICC=0.941) and intra-rater (ICC=0.986) reliability and concurrent validity (r=0.945) in measuring ITB tightness. Conclusion: From the cross-sectional study’s results, it can be concluded that the iPhone® measurement application possesses strong intra-rater and inter-rater reliability and concurrent validity and can be used for measuring ITB tightness.