# Visualization of Caregiving Posture and Risk Evaluation of Discomfort and Injury
## 3 Results
### Comparison of REBA and C-REBA  
When the Exp group and Inexp group caregivers were evaluated by our C-REBA method, there were significant differences between the Exp and Inexp groups at each individual stage (Stage 1: \(p\) < 0.01; Stage 2: \(p\) < 0.001; Stage 3: \(p\) < 0.001; Stage 4: \(p\) < 0.001; Stage 5: \(p\) < 0.05). This indicates that the C-REBA method could provide good differentiation in each stage of the caregiving task (Figure 9), as well as being suitable for providing guidance and reference for inexperienced caregivers. More specifically, the mean C-REBA scores for the Exp group in Stages 1-5 were all below eight points, at a medium risk level. For the Inexp group, on the other hand, the mean C-REBA scores were above eight points except for Stages 1 and 5. This indicated that the caregiving posture in Stages 2, 3, and 4 needed to be corrected to reduce musculoskeletal discomfort and injury risks. It also suggested that Stages 2, 3, and 4 might be the most meaningful caregiving posture intervention stages.  
To verify the improvement of C-Extra A and C-Extra C in C-REBA, we set up ablation experiments to verify the REBA scoring rules, REBA with C-Extra A scoring rules, and C-REBA (REBA with C-Extra A and C-Extra C) scoring rules. The scoring results of REBA and REBA with C-Extra A were significantly different (Table 3; all groups and all stages p1 < 0.05). The evaluation rules for C-Extra C focused on the caregiving power position and the load-bearing time. For the Exp group, they were familiar with the caregiving power position, and their load-bearing time was relatively short. Therefore, the C-Extra C rules had little effect on the Exp group. However, for the Inexp group, there were significant differences in Stages 2 (\(p\) < 0.001), 3 (\(p\) < 0.001), and 4 (\(p\) = 0.035) in the scoring results of REBA with C-Extra A and C-REBA, indicating that the Inexp group had a greater change in the COG and a longer load-bearing time in these stages. Thus, urgent intervention was needed in these stages. In addition, we calculated the proportion of high-risk (scores above eight points) frames in the caregiving process to assess the risk adaptability of these methods.  
\begin{table}
\begin{tabular}{c c} \hline
**Score** & **Rule** \\ \hline +1 & Large body tipping due to COG instability \\ +1 & Load-bearing time over 3.87 s \\ +1 & The COG height difference between Stage 1 and the highest point exceeds 7.54 cm \\ \hline \end{tabular}
\end{table}
Table 2: The C-Extra C scoring rule of C-REBA.  
Figure 9: The differences between the REBA and C-REBA scoring results; \(n\) = 8 in the Exp group, \(n\) = 10 in the Inexp group. NS = not significant, \({}^{\star}\)\(p\) < 0.05, \({}^{\star\star}\)\(p\) < 0.01, \({}^{\star\star\ast}\)\(p\) < 0.001. The red line represents a REBA score of 8 points.  
There was a significant difference (Table 4; all groups and all stages p1 \(<\) 0.05) in the results of the proportion of high-risk frames (scores above eight) between the REBA and C-REBA methods. For the Inexp group, the proportion of high-risk frames in Stages 2, 3, and 4 was high, indicating that the caregiving postures needed to be corrected in these stages. These results suggest that C-REBA avoided the problem of overassessment of caregiver posture. Also, the C-REBA method evaluated the COG changes in the caregiving power position and load-bearing time, and it provided reliable posture risk feedback for the caregivers.