This study’s objective was to assess the concurrent validity and reliability of the Simple Goniometer (SG) iPhone® app compared to the Universal Goniometer (UG). Design: Within subject comparison design comparing the UG with the SG app. AT James Cook University, Townsville, Queensland, Australia, 36 persons, with a mean age of 60.6 years (SD 6.2), volunteered . Thirty-six volunteers performed three standing lunges during which the knee joint angle was measured with the SG app and the UG. There weren’t any significant differences in the measures of individual knee joint angles between the UG and the SG app. Pearson correlations of 0.96-0.98 and intraclass correlation coefficients of 0.97-0.99 (95% confidence interval: 0.95-1.00) were recorded for all measures. Using the Bland-Altman method, the standard error of the mean of the differences and the standard deviation of the mean of the differences were low.
The study found that the measurements from the SG iPhone® app are reliable and have concurrent validity d when compared to the UG with the sample and protocol use.