Concurrent validity and intra-trial reliability of a bluetooth-embedded inertial measurement unit for real-time joint range of motion

Abstract Along with advancements in science and technology, anthropometric measurements using electronic devices have become possible, and research is being actively conducted on this topic. Recently, devices using Bluetooth that are portable because of their small size have been developed to allow real-time measurements and recording. This study investigated the concurrent validity and intra-trial reliability of a recently developed Bluetooth-embedded inertial measurement unit. Thirty-seven healthy, young adult participants (age = 22.1±1.2 years, height = 166.8±1.6 cm, mass = 61.9±12.3 kg) were included in the study. The knee extension angles during active knee extension were measured for validity, using both the Bluetooth-embedded inertial measurement unit and the standard goniometer. Intra-trial reliability was tested for consistency during repeated measurements. The intra-class correlation coefficients value for the concurrent validity between the Bluetooth-embedded inertial measurement unit and standard goniometer was 0.991, and the values for the intra-trial reliability of the two devices were 0.973 and 0.963, respectively. Based on its high validity and reliability, the Bluetooth-embedded device may be useful for evaluating functional impairment and exercise performance ability by real-time measurements of joint ranges of motion in clinical rehabilitation or sports fields.