Table 4.
Model selection and IMU sensor position for estimating ground reaction force.
| Reference | Number of Sensors | Position | Frequency | Activation | Tasks | Optimal Model | Accuracy |
|---|---|---|---|---|---|---|---|
| (Guo et al., 2017) [58] | 1 | L5 | 128 Hz | Walking | vGRF | OFR | Average prediction percentage error < 5% |
| (Wouda et al., 2018) [56] | 3 | Pelvis, lower legs | 240 Hz | Running | vGRF | ANN | Single subject training: ρ > 0.99, Multiple subject training: ρ > 0.9 |
| (Shahabpoor et al., 2018) [59] | 3 | C7, L5, thigh | 128 Hz | Walking | Tri-Axial GRF | Linear regression | NRMSE: vGRF: 7%, A-P GRF: 16%, M-L GRF: 18% |
| (Lim et al., 2019) [16] | 1 | CoM | 100 Hz | Walking | A-P GRF, vGRF |
ANN | The approximate errors: vGRF: 58 N, A-P GRF: 23 N |
| (Johnson et al., 2021) [8] | 5 | Pelvis, thigh, shank | Virtual IMU data | Sidestepping, running |
Tri-Axial GRF | CaffeNet | Pearson correlation coefficient: 0.89 |
| ResNet-50 | Pearson correlation coefficient: 0.87 | ||||||
| (Jiang et al., 2020) [98] | 1 | Shank | 100 Hz | Walking | vGRF | Random forest regressor | Intra-subject test: RMSE = 0.02 BW Inter-subject test: RMSE = 0.10 BW |
| (Lee and Park, 2020) [9] | 1 | Sacrum | 148 Hz | Walking | Tri-Axial GRF | ANN | NRMSE: Tri-Axial GRF: 6.7–15.6%, |
| (Dorschky et al., 2020) [10] | 4 | Lower back, the right thigh, shank and foot | 1000 Hz | Walking, Running | A-P GRF, vGRF | CNN | Pearson correlation coefficients: A-P GRF: 0.970 vGRF: 0.980 |
| (Chaaban et al., 2021) [60] | 4 acc, 4 gre | Thigh, shank | 1125 Hz | Jumping | vGRF | Linear regression | RMSE: 0.22 ± 0.002 BW |
| 4 acc | RMSE: 0.25 ± 0.003 BW | ||||||
| (Tedesco et al., 2021) [64] | 2 | Left and right shanks | 238 Hz | Running | vGRF | ANN | RMSE: 0.148 BW |
| (Alcantara et al., 2022) [14] | 3 | Two on the right shoe and one on the sacrum | 2000 Hz | Uphill and downhill running | Perpendicular to running surface GRF | RNN | RMSE: 0.16 ± 0.04 BW |
| (Zhu et al., 2023) [57] | 5 | Pelvis, left thigh, left ankle, right thigh, and right ankle | 100 Hz | Fast running, jogging, slow walking, brisk walking, and walking up and down stairs | vGRF | Transformer | MSE: 0.0205 |
OFR: Orthogonal forward regression, vGRF: Vertical ground reaction force, A-P: Anterior–posterior ground reaction force, CoM: Center of mass, L5: 5th lumbar vertebrae, C7: 7th cervical vertebrae, NRMSE: Normalized root mean square error, RMSE: Root mean square error, MSE: Mean squared error.