MOVEMENT MEASUREMENT VALIDITY AND RELIABILITY OF THE IMAGE J PROGRAM FOR KINEMATIC ANALYSIS

Background: While advanced motion analysis systems can provide accurate kinematic information, the majorities of motion analysis systems are stationary, expensive and time consuming. Image J is a Java-based image processing program that was originally developed at the National Institutes of Health and has rapidly gained widespread acceptance among rehabilitation specialists as a portable and affordable alternative motion analysis system. However, the validity and reliability of the Image J program have not been well established. Objective: The purpose of this study was to investigate the validity and test-retest reliability of the Image J kinematic analysis system. The Image J kinematic analysis system is designed to produce precise kinematic evidence during normal and pathological static and dynamic movement patterns. Methods: The Image J motion analysis system was concurrently compared with the electrogoniometer system as a reference standard measure by obtaining sagittal kinematic knee joint angle data. Results: Image J motion analysis system measurement revealed outstanding validity (R-2 = 0.976; r = 0.988 and p < 0.01). The test-retest reliability for kinematic knee angle data showed remarkable consistency (Cronbach's alpha = 0.994). Conclusions: This study provides the first evidence highlighting the Image J kinematic analysis system's excellent validity and reliability for evaluating human kinematic movements in elderly people with hemiparetic stroke.