**4. Results**

Average classification accuracies in every fold for the Knee, KEMG, and Reference approaches are shown in Table 1 for the learned-test set (LS-test) and in Table 2 for unlearned set (US). Figure 3 depicts a direct comparison of accuracy provided in each fold by Knee (red bars) vs. KEMG approach (blue bars). The direct comparison between mean values (horizontal dashed lines) shows a significant improvement of 4 points (94.6 ± 2.3% vs. 90.6 ± 2.9%, *p* < 0.05) of the classification accuracy provided by KEMG approach, compared with Knee approach. Starting from stance vs. swing classification, the present study is able to predict also the signal of foot–floor contact and to estimate gait events. An example of predictions of foot–floor-contact signal provided by Knee vs KEMG approaches is depicted in Figure 4. Tables 3 and 4 report the performance in US of HS and TO prediction in terms of mean absolute error (MAE), precision, recall, and F1-score. MAE detected in the prediction of HS provided by the Knee approach is significantly higher than MAE assessed by KEMG and Reference approaches (29.4 ± 13.7 ms vs. 18.8 ± 7.9 ms and 21.6 ± 7.0 ms; *p* < 0.05). Similarly, a significant higher MAE is observed in TO prediction provided by Knee approach (99.5 ± 28.9 ms vs. 35.9 ± 20.6 ms and 38.1 ± 14.2 ms; *p* < 0.05). No further significant di fferences were detected between groups.




**Table 2.** Stance vs. swing classification accuracy provided in US

**Figure 3.** Direct comparison of classification accuracy provided in each fold by Knee (red bars) vs. KEMG approach (blue bars). Average values over 23 folds are represented with horizontal dashed lines.

**Figure 4.** Example of predictions of foot–floor-contact signal in the same five strides of a representative subject, achieved by Knee (red dotted line) and KEMG (blue dotted line) approaches. Predictions are compared with the ground truth (black solid line).

**Table 3.** MAE (mean absolute error), precision, recall, and F1-score provided by Knee, KEMG, and reference (Ref) approach for heel strike (HS) prediction.


\* means *p* < 0.05 between Knee and KEMG approach.


**Table 4.** MAE (mean absolute error), precision, recall, and F1-score provided by Knee, KEMG, and reference (Ref) approach for toe o ff (TO) prediction.

\* means *p* < 0.05 between Knee and KEMG approach.
