Verification of Reliability and Validity of Trunk Forward Tilt Angle Measurement During Gait Using 2-Dimensional Motion Analysis

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 ​​of 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 ​​using 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.