RESUMEN
Objective: The purpose of this study was to verify the reliability and validity of trunk forward tilt angle measurement during gait using the 2-dimensional motion analysis, open-source software Kinovea. Methods: The participants were 48 healthy people (23.3 ± 3.7 years of age), and the measurement task was normal gait. Two-dimensional motion analysis using Kinovea and measurement using a 3-dimensional motion analyzer were performed synchronously to calculate the forward tilt angle of the trunk during gait. The maximum and minimum values ââof the trunk forward tilt angle in 1 gait cycle were used as representative values. The intraclass correlation coefficient and the minimum detectable change amount in Kinovea were calculated. We also verified the correlation with the measured values ââusing the 3-dimensional motion analyzer and the error by Bland-Altman analysis. Results: The intraclass correlation coefficient for Kinovea was 0.925 (95% confidence interval, 0.866-0.958) at the maximum and 0.918 (95% confidence interval, 0.854-0.954) at the minimum. The maximum value of the minimum detectable change amount was 2.7°, and the minimum value was 2.9°. The correlation coefficient between the methods was the maximum value r = 0.964 (R² = 0.929) and the minimum value r = 0.970 (R² = 0.941). The average difference between the methods (d) was -0.55 to -0.51° and the standard deviation of the difference between the measured values was 0.66 to 0.84°, and the minimum value was d = -0.59 to -0.54° and SDd = 0.63 to 0.91°. Conclusion: The reliability and validity of the measurement by 2-dimensional motion analysis of the trunk forward tilt angle in young adults were confirmed.