## 3 Results
### Analysis of Secondary Outcomes and Data Imputation
A comparison of changes in the MAS scores, joint ROM, and pain perception measurements pre- and post-intervention between the shaking exercise and control groups showed no statistically significant differences for any of the parameters measured (Appendix A). Significant within-group changes in the control group were particularly notable in MAS elbow extension (W = 19.5, \(p\) = 0.005, effect size r = \(-\)0.839) and MAS wrist flexion (W = 6.0, \(p\) = 0.083, effect size r = \(-\)0.861). The other scores in the control group did not show statistically significant differences. In the intervention group, although there were no statistically significant overall changes, the MAS wrist flexion score showed a moderate effect size (W = 97.5, \(p\) = 0.206, effect size r = \(-\)0.720). In within-group comparisons of the intervention group, the most significant change was observed in active shoulder extension ROM (W = 93.0, \(p\) = 0.011, effect size r = \(-\)0.727), indicating a statistically significant decrease in shoulder extension ROM following the intervention. Other ROM measurements showed no significant changes, with effect sizes indicating slight to moderate reductions, such as in passive elbow extension ROM (W = 97.0, \(p\) = 0.512, effect size r = \(-\)0.721) and passive wrist extension ROM (W = 162.5, \(p\) = 0.056, effect size r = \(-\)0.620). In the control group, no significant changes were observed in most ROM measurements after treatment. However, notable changes with moderate effect  
\begin{table}
\begin{tabular}{c c c c|c c c c|c c c c} \hline \hline \multicolumn{2}{c|}{} & \multicolumn{2}{c|}{**Variables**} & \multicolumn{4}{c|}{**Intervention Group**} & \multicolumn{4}{c|}{**Control Group**} & \multicolumn{4}{c}{**\(\Delta\) Control vs.**} \\ \multicolumn{2}{c|}{} & & \multicolumn{2}{c|}{**Pre**} & \multicolumn{2}{c|}{**Post**} & \multicolumn{2}{c|}{**Delta**} & \multicolumn{2}{c|}{**Pre**} & \multicolumn{2}{c|}{**Post**} & \multicolumn{2}{c|}{**Delta**} & \multicolumn{2}{c}{**U**} & \multicolumn{2}{c}{**\(p\)**} & \multicolumn{2}{c}{**r**} \\ \hline \multirow{4}{*}{
\begin{tabular}{c} **Vas. ** \\ **Vas. ** \\ **Vas. sizes were identified for several measurements, although they did not reach statistical significance at conventional thresholds. This method allowed us to statistically estimate missing data based on available patient information and characteristics observed in complete cases. Table 11 presents the results of the PP analysis of the secondary outcomes. Using nonimputed data, patients in the intervention group maintained a significantly greater active ROM in shoulder extension (A5.4 vs. \(\Delta-1.3\)) and wrist active flexion (6.6 vs. 1.5; \(p=0.03\)), as well as less pain (\(-0.61\) vs. 0.15) than the control group. All participants adhered to the assigned intervention or control group throughout the study, and no crossover between groups occurred. Although participants were absent from training sessions and adhered to the prescribed regimen, some protocol deviations were observed. For example, participants were sometimes unable to grasp the lever of the shaking device with their affected hand. These deviations were addressed by providing assistance to therapists or by installing a holding jig to prevent any impact on the training. Only \(1/47\) patients (2.1%) in the test group experienced an adverse event that was undeniably related to the shaking device. The patient experienced mild pain in the clavicular area, which improved with follow-up. There were no adverse events in the control group.