Affiliations: [a] École de réadaptation, Faculté de Médecine et des Sciences de la santé, Université de Sherbrooke, Sherbrooke, Qc, J1H 5N4, Canada
| [b]
Centre de recherche du Centre hospitalier universitaire de Sherbrooke (CRCHUS), Sherbrooke, QC, Canada
Correspondence:
[*]
Corresponding author: Yannick Tousignant-Laflamme, pht, Ph.D., School of Rehabilitation, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, Qc, J1H 5N4, Canada. Tel.: +1 819 821 8000/Ext. 72912; Fax: +1 819 820 6864; E-mail: yannick.tousignant-laflamme@usherbrooke.ca.
Abstract: BACKGROUND:Recent smartphones are equipped with gyroscopic functions enabling measurement of joint range of motion (ROM). Previous studies have demonstrated that the use of the iPod™ to measure shoulder ROM shows good reliability. However, evidence of concurrent validity of shoulder ROM taken with an iPod™ remains scarce. Thus, the aim of this study was to investigate the concurrent criterion validity of the gyroscopic functions of the iPod™, for the measurement of shoulder joint ROM. METHODS:A trained examiner measured shoulder ROM for the movements of flexion, abduction, extension and external rotation. For each movement, four to six trials (repetitions) were performed at different angles, in order to obtain values for the entire available ROM. Measures were simultaneously taken with the iPod™ (5th generation) and a digital inclinometer (gold standard). Validity was estimated using the Intraclass Correlation Coefficient (ICC) and mean differences (MD), as well as 95% limits of agreement (LOA) with Bland-Altman plots. RESULTS:ROM data was collected from 28 healthy participants. We found excellent criterion validity for all four movements studied (ICCs = 0.907–0.996). In terms of accuracy, the MD between both instruments for all movements was between –1.9° and 2.0°, except for extension (MD = 3.80°–4.70°). CONCLUSIONS:This study provides evidence of validity of the gyroscopic functions of the iPod™ for the measurement of the shoulder ROM in a wide range of amplitudes. The use of an armband to position the instrument can minimize potential measurement errors compared to conventional goniometry. However, future studies should investigate ways to improve accuracy of extension measurements.
Keywords: Shoulder joint, range of motion, validity, smartphone, accuracy
