## 3 Results
### Post-Trials Interviews and Insights  
From the post-trial interviews, we noted most of the subjects suffered from fatigue at the start of the program. Some of them possessed pain in the lower trunk because of prior spine surgery. When they were asked about the trunk exercises using the proposed exercise design, they said that our exercise program was helpful and better than conservative treatments that involve complicated physiotherapeutic and clinical methods. We asked the subjects, (a) what did you expect from the 5 weeks exercise program?, and (b) what did you think you are likely to learn about your back pain condition and its intensity (low, high, or medium) after and before the exercise program? In responding to these questions, subjects F, G, and H reported the following answers (as translated into English translation):  
Subject F noted:  
\"I didn't even know what it was when I received the new one [new version of the exercise object], but it was so nice to try it. I didn't expect much at first. Normally, back pain doesn't affect much my daily life, but it was good for my back... \".  
\"I thought my back would get better if I just do what the exercise program guided me to do so... \".  
Subject G noted:  
\"I hoped that my muscle strength would improve through the exercise program. I didn't expect anything but I just thought it would be better to do exercise to improve muscle strength, develop good posture, and give strength to my legs beside my back... \".  
\"I didn't expect what I learned. My knee got a lot worse, but it got a lot better after this program. I thought it would be better if I do this program again... \".  
And subject H noted:  
\"I had a bend back, but I wanted to make my postures correct, and it seemed to straighten my back. I hoped my body would get better by exercising with the new exercise object. I wanted my body to have muscles and become lighter... \".  
\"I didn't know what I learned, but I just wanted to do exercise with the object.  
My body feels refreshed when I perform the exercise program... \".  
Overall, the subjects expressed favorable views about the exercise training along with the exercise object. According to them, the training helped decrease their LBP. Some of those interviewed also believed that training reduced their leg pain. They elaborated that the exercise object with a 10-15\({}^{\circ}\) slope angle benefits muscle relaxation and posture correction. Subjects requested to take the training object and the printed manual of the exercise program back to their homes to maintain the training in their domestic settings. They believed the training helped them with their knees, shoulders, and waist, and they also wanted to suggest the exercise training to their families and friends. To a large extent, we observed considerable improvements in the subjects' health conditions based on the current results with the exercise program. Table 12 below and Supplementary Material D present detailed descriptions of the revised exercise program design and its points of effect in the body.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Dependent Variable** & **Effect** & **F Statistics** & **\(p\) Two-Tailed** & \(\mathbf{\eta^{2}}\) \\ \hline \multirow{4}{*}{Perceived LBP} & Treatment groups (between-subject) & F (1, 14) = 12.4 & 0.01 * & 0.47 \\  & Time (within-subject) & F (2, 28) = 47.9 & 0.01 * & 0.77 \\  & Treatment groups \(\times\) Time & F (4, 56) = 0.89 & 0.64 & 0.06 \\ \hline \hline \end{tabular}  
\end{table}
Table 11: Repeated measures ANOVA test results in perceived LBP.