## 3 Experimental Results
### Evaluation of Reflex Control Model
Between the yellow lines and the blue lines, they are \(88.2\pm 6.1\%\) and \(90.4\pm 7.5\%\), respectively. The RMSEs of SOL and GAS between the red lines and the blue lines are \(0.03\pm 0.02\) and \(0.007\pm 0.004\), respectively. Between the yellow and blue lines, they are \(0.09\pm 0.03\) and \(0.024\pm 0.008\), respectively. The \(p\) values for the one-way ANOVA test of the VAFs between the red lines and the yellow lines are \(0.033\) for SOL and \(0.082\) for GAS. In terms of the RMSEs, the \(p\) values are \(0.019\) and \(0.0035\) for SOL and GAS, respectively. Considering a significance level of \(0.01\), there are no significant differences between the red lines and yellow lines, except for the RMSEs of GAS. The corresponding \(p_{a}\) and \(d_{a}\) values of Figure 10 are listed in Table 1. The relative standard deviation (SD/Mean) of \(p_{a}\) (SOL: 0.09, GAS: 0.19) is smaller than that of \(d_{a}\) (SOL: 0.69, GAS: 0.82). Compared with \(d_{a}\), the values of \(p_{a}\) do not change much. It seems that the \(d_{a}\) value is more sensitive to the disturbance. Figure 10: Reflex model fitting results of the forepart of subject A of the six trials. The blue lines are the muscle activation calculated from the measured sEMG signals. The red lines are the prediction results using individually calibrated reflex gains. The yellow lines are the prediction results using mean reflex gains. Figure 9: Variations of \(p_{a}\) and \(d_{a}\) of a single trial. The blue lines are the \(p_{a}\) and \(d_{a}\) values. The red lines are the VAF values of prediction results. Table 2 shows the mean reflex gains and prediction results for the remaining four subjects. It can be easily observed from Table 2 that, in comparison to the individual calculation results, the values of VAF based on mean gains prediction decreases. The minimum decrease value is 2.0%, in the prediction of the GAS activation of subject B, while the maximum value is 6.6%, in the prediction of the SOL activation of subject A. However, it is important to note that, despite showing a decreasing tendency in the values of VAF, they are still at a relatively high level (above 85%), which shows the potential of the mean value in real-time implementation. Differences in reflex gains among the subjects are listed in Table 3 (repeated two-sample t-test, 0.05 significance level). From this table, one can see that, on the one hand, the difference of \(p_{a}\) among subjects B, C and D is not significant, while on the other hand, the difference of \(d_{a}\) among subjects A, C and D is also not significant. Equation (1) is implemented to evaluate the rest of the muscle activation level. That is to say, the starting point is the end time point of the forepart, and the ending point is the time point at which muscle activation level returns to its quiet level. The fitting results for subject A are shown in Figure 11, in which the lines with different colors have the same meanings as those shown in Figure 10. The VAF values of SOL and GAS between the red lines and the blue lines are 90.4 \(\pm\) 8.1% and 93.0 \(\pm\) 7.5%, respectively. Between the yellow lines and the blue lines, they are, respectively, 64.9 \(\pm\) 12.9% and 67.5 \(\pm\) 20.9%. RMSEs of SOL and GAS between the red lines and the blue lines are 0.05 \(\pm\) 0.02 and 0.01 \(\pm\) 0.005, respectively. Between the yellow and the blue lines, they are 0.17 \(\pm\) 0.09 and 0.041 \(\pm\) 0.020, respectively. The \(p\) values of the one-way ANOVA test of the VAFs between the red lines and the yellow lines are