Table 4.

Sensor-based features extracted from the CST Test.

Feature	Sensor	Task	Description
SD Duration	Accelerometer/Gyroscope	Sit-to-Stand, Stand-to-Sit	Standard deviation of the duration of each subtask of the test.
Duration [s]	Accelerometer/Gyroscope	Total, Sit-to-Stand, Stand-to-Sit	Duration of each subtask of the test.
NJS AP ML V [m]	Accelerometer	Sit-to-Stand, Stand-to-Sit	Normalized Jerk Score of the acceleration (it is related with the smoothness of the movement): $$NJS=\sqrt{\frac{T^5}{2}{{\displaystyle \int }}_{Tstart}^{Tend}{(\dot{a})}^{2}dt}$$ where T is the duration (Tend-Tstart) of the considered sub-task and a is the acceleration measured in m/s2.
Range AP ML V [m/s2], [°/s]	Accelerometer, Gyroscope	Sit-to-Stand, Stand-to-Sit	Range of the signal, during the considered sub-task of the test
RMS AP, ML, V [m/s2], [°/s]	Accelerometer, Gyroscope	Sit-to-Stand, Stand-to-Sit	Root Mean Square (RMS) of the signal, s, during the considered sub-task of the test (it is a measure of dispersion): $$RMS=\sqrt{\frac{1}{N}}{\displaystyle \sum }_{i=1}^N{\left(s_i -m\right)}^2$$ where N is the total number of points of the signal s, and m is the mean value $mean\left(s\right)$

ACRONYMS: AP: Antero-Posterior; ML: Medio-Lateral; NJS: Normalized Jerk Score; RMS: Root Mean Square; SD: Standard Deviation; V: Vertical.