# Development of an Estimation Formula to Evaluate Mission Motion Suitability of Military Jackets
## 3 Results
### Development of Motion Suitability Evaluation Estimation Formula for Mission Motion  
Analysis of the correlation between mission motion and general motion (Table 6) revealed that there was a highly positive correlation between ammunition stowing I and ammunition stowing II with the stand erect, shoulder flexion 180\({}^{\circ}\), shoulder extension, horizontal shoulder adduction 90\({}^{\circ}\), and trunk flexion (\(p<0.001\)). The reason ammunition stowing I and ammunition stowing II motion was positively correlated with the stand erect posture is that the collar and hem of the current tracked vehicle crew jacket are ribbed, so even in the stand erect posture, discomfort in the waist and neck influenced the evaluation. In addition, most of the ammunition loading motions showed a high correlation with the general motions related to the shoulder joint use motions, including the trunk flexion used in receiving ammunitions, as this is conducted in pairs. Boarding and entry were correlated with the trunk flexion (\(p<0.01\)) and shoulder flexion 180\({}^{\circ}\) (\(p<0.05\)), but their correlations with shoulder flexion 180\({}^{\circ}\) were as low as 0.35 and 0.33, respectively. A multiple linear regression analysis was performed using general motions that showed a correlation of 0.4 or higher as the independent variable (\(p<0.01\), \(p<0.001\)), with respect to the main mission motions of the tracked vehicle crew, such as ammunition stowing I, ammunition stowing II, boarding, and entering. Regression equations for ammunition stowing I and ammunition stowing II were derived using the stand erect, shoulder flexion 180\({}^{\circ}\), shoulder extension, horizontal shoulder adduction 90\({}^{\circ}\), and trunk flexion as independent variables for the regression analysis (\(p<0.001\)). For boarding and entry, a regression equation was derived using trunk flexion as the independent variable (\(p<0.01\), \(p<0.05\)). The equations for estimating the mission motion suitability of the tracked vehicle crew based on general motion are listed in Table 7. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Motion** & **Boarding** & **Entry** & **Ammunition** & **Ammunition** \\  & & & **Sowing I** & **Sowing II** \\ \hline Stand Erect & 0.324 & 0.356 & 0.710 *** & 0.644 *** \\ Neck rotation & 0.142 & 0.319 & 0.328 & 0.331 \\ Shoulder flexion 90\({}^{\circ}\) & 0.128 & 0.117 & 0.369 & 0.352 \\ Shoulder flexion 180\({}^{\circ}\) & 0.355 * & 0.326 * & 0.627 *** & 0.641 *** \\ Horizontal shoulder & \(-\)0.078 & 0.054 & 0.182 & 0.270 \\ abduction 90\({}^{\circ}\) & 0.243 & 0.169 & 0.282 & 0.230 \\ Shoulder extension & 0.289 & 0.195 & 0.709 *** & 0.805 *** \\ Horizontal shoulder & & & & \\  & & & & \\  & & & & \\  & & & & \\  & & & & \\  & & & & \\  & & & & \\ \end{tabular}
\end{table} 
Table 6: Correlation results between general motion and mission motion (\(n=27\)). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Motion** & **Equation** & **R** & **R\({}^{2}\)** & **SEE** & **F** \\ \hline Ammunition & y = \(-\)0.192 + 0.490H + & & & & \\  & 0.356A \(-\) 0.406D + & 0.870 & 0.756 & 0.698 & 13.017 *** \\  & 0.170G + 0.245I & & & & \\ \hline Ammunition & y = 0.170 + 0.243H + & & & & \\  & 0.003A \(-\) 0.189D + & 0.848 & 0.718 & 0.652 & 10.753 *** \\  & 0.582G + 0.213I & & & & \\ \hline Boarding & y = 1.283 + 0.519I & 0.521 & 0.271 & 0.242 & 9.314 *** \\ \hline Entry & y = 1.521 + 0.456I & 0.462 & 0.213 & 0.182 & 6.784 * \\ \hline \hline \end{tabular}  
* A, stand erect; D, shoulder flexion 180\({}^{\circ}\); G, shoulder extension; H, horizontal shoulder adduction 90\({}^{\circ}\); I, trunk flexion. \(p*<0.05\), \(p*<0.01\), \(p*==0.001\).  
\end{table} 
Table 7: Estimation formula of main mission motion suitability (\(n=27\)). There was a significant positive correlation between ammunition stowing I and ammunition stowing II (r = 0.829, \(p\) < 0.01), as well as between boarding and entering (r = 0.833, \(p\) < 0.01), and each factor also had a high factor load (0.975, 0.962, respectively).