Table 1
Definition of metrics used in the present study.
| Metric | Definition (units) |
| Position metrics | |
| Standing/walking | Time spent standing or walking (%) |
| Sitting | Time spent sitting (%) |
| Lying | Time spent lying (%) |
| Steps | |
| Daily step count | Average steps walked per day |
| Base gait metrics | |
| Gait velocity | Distance traveled per second (m/s) |
| Step length | Distance between 2 consecutive contacts of any foot with the ground (m) |
| Step time | Time between 2 consecutive contacts of any foot with the ground (s) |
| Double support | Percentage of time where both feet are in contact with the ground (%) |
| Derivative gait metrics | |
| Symmetry score | Gait symmetry index (score from 0–100), calculated as the sum of the 3 components below.
|
| Gait velocity variability score | Step-to-step variability of gait velocity, calculated as the coefficient of variation (CoV):
|
| WORM score | Quantifies the stability, or “figure-of-8” motion of a subject’s trunk during walking as an indicator of falls-risk with exact calculations by Mobbs et al.23 |
Abbreviation: WORM, walking orientation randomness metric.
Note: Position metrics, steps, and base gait metrics are directly calculated by the sensor. Derivative gait metrics are mathematically derived from the base gait metrics and are not directly calculated by the sensor. Symmetry is related to differences between the left and right leg. Variability is related to differences in gait velocity between each step.