## 3 Results
### Muscle Synergies  
The 98% VAF led to the actual and reconstructed muscle activation patterns closely matching one another (as in Figure 3); however, Tables 6 and 7 display the average number of synergies for 80%, 90%, and 98% VAF with a constant confidence interval of 90% for healthy and stroke participants, respectively. In order to include all information from the EMG sensors and not to compromise accuracy, the choice was made to further examine synergies with a higher VAF (98%).  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**VAF**} & \multicolumn{5}{c}{**Walking Condition**} \\ \cline{2-7}  & \multicolumn{2}{c}{**FW**} & \multicolumn{2}{c}{**BW**} & \multicolumn{2}{c}{**FT-W**} & \multicolumn{2}{c}{**BT-W**} \\ \cline{2-7}  & **Pre** & **Post** & **Pre** & **Post** & **Pre** & **Post** & **Pre** & **Post** \\ \hline
80\% & 1.00 & 1.00 & 1.05 & 1.00 & 1.03 & 1.00 & 1.00 & 1.00 \\ \hline
90\% & 1.31 & 1.27 & 1.23 & 1.11 & 1.30 & 1.17 & 1.19 & 1.19 \\ \hline
98\% & 3.02 & 3.00 & 3.25 & 3.06 & 3.41 & 3.26 & 3.65 & 3.42 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Healthy group’s number of muscle synergies for 80%, 90%, and 98% VAF with constant confidence interval of 90%.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Muscle**} & \multicolumn{2}{c}{**Cohen’s \(d\)**} \\ \cline{2-5}  & **Walking** & **Walking** & **Backward** & **Tandem** & **Tandem** \\  & **Forward** & **Pre vs. Post** & **Pre vs. Post** & **Pre vs. Post** & **Pre vs. Post** \\ \hline RRF & 0.2 & 0.75 & 0.0 & \(-1.9\) \\ \hline LRF & 0.4 & 1.9 & \(-0.5\) & \(-3.2\) \\ \hline RTA & \(1.1\) & 2.6 & 1.7 & 2.1 \\ \hline LTA & 0.0 & \(-1.4\) & 2.5 & 1.2 \\ \hline LBF & 1.1 & 2.3 & 2.0 & 2.8 \\ \hline RBF & 1.5 & 1.3 & 1.5 & 1.1 \\ \hline LMG & 0.8 & 0.7 & 1.3 & 2.6 \\ \hline RMG & 1.0 & 1.4 & 0.6 & 0.9 \\ \hline \hline \end{tabular}
\end{table}
Table 5: [PERSON]’s \(d\) results for pre- vs. post-training for stroke participants in all walking conditions. Small (red), medium (blue), and large (green) effect sizes are noted in the table; a negative symbol is shown to indicate directionality.  
Table 8 displays the average number of muscle synergies and standard deviations for 98% VAF used for each group for each walking condition. From the results, it is observed that there were increases, on average, in the healthy group from easier (FW) to most difficult (BT-W) conditions. It is important to note that for BT-W (the hardest walking condition), for stroke, only the participants who felt the most comfortable and confident with their walking ability attempted; others opted out or could not complete it. Conversely, within each walking condition, there were slight decreases in numbers of synergies used post-compared to pre-training. For healthy adults, there were decreases in synergies, on average, post- compared to pre-training. Further, for BW and FT-W in the stroke group, there were decreases in the number of synergies, whereas for FW and BT-W there were increases in the number of synergies post- compared to pre-training.  
Table 8 above shows the average number of muscle synergies for each walking condition within each group and their standard deviations in parentheses. For data shown in the above table, we compared the number of muscle synergies 1) within each group (healthy pre- vs. post-training and stroke pre- vs. post-training) for each walking condition and 2) within each walking condition across groups (e.g., stroke FW vs. healthy FW). We performed a non-parametric significance test (Kruskal-Wallis) using RStudio software (RStudio Version 2023.12.1, Boston, MA, USA) to test for significant differences where significance was defined as a \(p\)-value \(<\) 0.05. It was determined that the number of synergies for backward walking (BW) compared to backward tandem walking (BT-W) for both the healthy and stroke groups were found to be significant (\(p\) = 0.01 and 0.008, respectively). All other comparisons were not found to be statistically significant.