Table 5.
Original and optimal cutoff frequency for each IMU at different transitions during a TUG
| Transition | IMU 1 | f cutoff (Hz) | IMU 2 | f cutoff (Hz) | ||
|---|---|---|---|---|---|---|
| Org. | Opt. | Org. | Opt. | |||
| Sit-to-stand | Trunk a z | 1.57 | -- | Hip θ | 0.69 | -- |
| Stand-to-walk out | Trunk a z | 2.44 | -- | |||
| Walk out-to-turn | Trunk ωy | 1.32 | -- | Sacrum ωy | 0.98 | --- |
| Turn-to-walk in | Sacrum ωy | 0.53 | 3.0 | |||
| Walk in-to-turn | Trunk ωy | 1.00 | 3.0 | Sacrum ωy | 0.59 | 3.0 |
| Turn-to-stand | Trunk ωy | 0.81 | 2.0 | Sacrum ωy | 1.00 | 2.5 |
| Stand-to-sit | Trunk a z | 1.02 | -- | |||
The high cutoff frequency (f cutoff) of the band pass filter was re-optimized during more dynamic transitions to increase the accuracy of the segmentation. The optimal range of these cutoff frequencies was between 0.5–3.0 Hz