## 2 Materials and Methods
### Post-Stroke Participants
#### 3.2.2 Glass Grip  
The glass grip exercise measured how well participants flex their fingers around a cylindrical object resembling a drinking glass. Participants reached out and wrapped their fingers around a 6 cm-diameter, 10 cm-tall cardboard tube engineered to simulate the feel and weight of a filled glass. We compared trials without actuation to those with left-side and right-side assistance from the SRPAS to see if and how the device alters grip coordination. From each trial, we extracted both time-domain and frequency-domain features, then used PCA to reveal clear groupings of sensor patterns under each condition. Figure 11: HER-01-001—EMG and accelerometer data FFT spectra—ball grasping: (a) right hand and (b) left hand. Figure 12: HER-02-001—EMG and accelerometer data FFT spectra—ball grasping: (a) right hand and (b) left hand. \begin{table}
\begin{tabular}{l l c c c c} \hline \hline
**Participant** & **Condition** & \begin{tabular}{c} **LH EMG Dominant** \\ **Freq (Hz)** \\ \end{tabular} & \begin{tabular}{c} **LH EMG Total** \\ **Power (\(V^{2}\))** \\ \end{tabular} & \
\begin{tabular}{c} **RH EMG Dominant** \\ **Freq (Hz)** \\ \end{tabular} &
\begin{tabular}{c} **RH EMG Total** \\ **Power (\(V^{2}\))** \\ \end{tabular} \\ \hline HER-01-001 & Non-actuated & 0.099354 & 1830.000000 & 0.099354 & 1830.000000 \\ HER-01-001 & Left Actuation & 0.796495 & 1890.282550 & 0.199124 & 1854.152767 \\ HER-01-001 & Right Actuation & 0.299880 & 1830.000000 & 0.099960 & 1830.000000 \\ HER-02-001 & Non-actuated & 0.200361 & 1886.492856 & 0.400721 & 1889.190431 \\ HER-02-001 & Left Actuation & 0.099562 & 1887.675208 & 0.298686 & 1883.218107 \\ HER-02-001 & Right Actuation & 0.701262 & 1890.172429 & 0.500902 & 1888.627353 \\ HER-02-002 & Non-actuated & 0.398248 & 1890.866749 & 0.099562 & 1890.583968 \\ HER-02-002 & Left Actuation & 0.400721 & 1890.911656 & 0.100180 & 1823.081392 \\ HER-02-002 & Right Actuation & 0.300541 & 1886.715516 & 0.200361 & 1890.946518 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Frequency-domain features for EMG sensors—ball grasping exercise. Figure 13: HER-02-002—EMG and accelerometer data FFT spectra—ball grasping: (a) right hand and (b) left hand. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline
**Participant** & **Condition** & \begin{tabular}{c} **LH Accel Dominant** \\ **Freq (Hz)** \\ \end{tabular} & \begin{tabular}{c} **LH Accel Total** \\ **Power (\(V^{2}\))** \\ \end{tabular} & \
\begin{tabular}{c} **RH Accel Dominant** \\ **Freq (Hz)** \\ \end{tabular} &
\begin{tabular}{c} **RH Accel Total** \\ **Power (\(V^{2}\))** \\ \end{tabular} \\ \hline HER-01-001 & Non-actuated & 0.099354 & 1830.000000 & 0.099354 & 1830.000000 \\ HER-01-001 & Left Actuation & 0.099562 & 1888.322165 & 0.099562 & 1888.413307 \\ HER-01-001 & Right Actuation & 0.399840 & 1830.000000 & 0.233240 & 1830.000000 \\ HER-02-001 & Non-actuated & 1.035197 & 1889.605088 & 0.300541 & 1890.473058 \\ HER-02-001 & Left Actuation & 0.696933 & 1880.280903 & 0.398248 & 1884.340688 \\ HER-02-001 & Right Actuation & 0.233754 & 1875.938184 & 0.233754 & 1881.659661 \\ HER-02-002 & Non-actuated & 0.099562 & 1889.261171 & 0.099562 & 1888.783603 \\ HER-02-002 & Left Actuation & 0.400721 & 1889.190340 & 1.268951 & 1885.319101 \\ HER-02-002 & Right Actuation & 1.068590 & 1867.917990 & 1.703066 & 1871.429125 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Frequency-domain features for accelerometer sensors—ball grasping exercise. Figure 14: Ball grasping exercise—PCA time and frequency domain features. Figure 15: Flex peak amplitude—glass grip: (**a**) HER-01-001 right hand; (**b**) HER-01-001 left hand; (**c**) HER-02-001 right hand; (**d**) HER-02-001 left hand; (**e**) HER-02-002 right hand; (**f**) HER-02-002 left hand. Figure 16: HER-01-001—EMG and accelerometer data FFT spectra—glass grip: (**a**) right hand and (**b**) left hand.