Reference values for instrumented Timed Up and Go—outcomes of vertical accelerations and angular velocities in healthy subjects

Background: Gait is a fundamental function, and instrumented timed up and go (iTUG) has become a widely used gait analysis tool. Reference values of healthy populations are recommended when assessment technologies are used in clinical settings. The aim of this study is to establish reference values ​​for iTUG subphases (accelerations and angular speeds) among healthy subjects. Methods: This is a cross-sectional study with 79 healthy subjects who took the iTUG test with a G-Walk inertial wearable system. The variables of vertical, anteroposterior, and lateral accelerations during the sit-to-stand and stand-to-sit subphases and the average rotation speed during the mid and final turnings were collected from the wearable device and stored in electronic media for analysis. Clinical and demographical characteristics were also collected and tested with simple linear regression as covariables of the gait characteristics. The bootstrapped fifth and 95th percentiles of the parameters were described as the reference values for iTUG measured by G-Walk. Results: The study analyzed 79 healthy volunteers. They were mostly women (67.07%), aged 40.40 (SD: 13.21). None of the demographic variables were associated with the iTUG parameters, therefore, no statistical correction was required. Vertical accelerations below 3 m/s 2 , anteroposterior below 2 m/s 2 , and lateral accelerations below 1 m/s 2 during the sit-to-stand phase and 2 m/s 2 during the stand-to-sit phase were considered atypical. Likewise, turnings below 60 deg/s exceed the established reference value. Conclusions: Our study established reference values for subphases of the iTUG test measured with the wearable sensor G-Walk for a population of a major urban area.