# Verification of Industrial Worker Walking Efficiency with Wearable Hip Exoskeleton
## 3 Results
### Climbing Stairs
#### 3.2.2 Energy Expenditure  
Table 5 shows the results of the energy expenditure analysis for climbing the stairs to the fifth floor.  
\begin{table}
\begin{tabular}{c c c c c c} \hline  & & **No WIM** & **WIM** & **\% Difference** & **t-Value** \\ \hline \multirow{4}{*}{RF} & Muscle activity & \multirow{2}{*}{19.90 \(\pm\) 11.63 \({}^{\$}\)} & \multirow{2}{*}{16.56 \(\pm\) 9.87} & \multirow{2}{*}{\(-\)16.78\%} & \multirow{2}{*}{3.404 \({}^{\ast\ast}\)} \\  & (\%MVC) & & & & \\ \cline{2-5}  & Muscle fatigue & \multirow{2}{*}{0.005 \(\pm\) 0.050} & \multirow{2}{*}{\(-\)0.040 \(\pm\) 0.057} & \multirow{2}{*}{\(-\)873.08\%} & \multirow{2}{*}{1.923} \\  & (Hz) & & & & \\ \hline \multirow{4}{*}{ST} & Muscle activity & \multirow{2}{*}{14.06 \(\pm\) 7.99} & \multirow{2}{*}{12.47 \(\pm\) 7.69} & \multirow{2}{*}{\(-\)11.32\%} & \multirow{2}{*}{3.234 \({}^{\ast\ast}\)} \\  & (\%MVC) & & & & \\ \cline{2-5}  & Muscle fatigue & \multirow{2}{*}{\(-\)0.024 \(\pm\) 0.074} & \multirow{2}{*}{0.026 \(\pm\) 0.069} & \multirow{2}{*}{\(-\)206.15\%} & \multirow{2}{*}{\(-\)2.014} \\  & (Hz) & & & & \\ \hline \multirow{4}{*}{TA} & Muscle activity & \multirow{2}{*}{15.73 \(\pm\) 5.05} & \multirow{2}{*}{14.75 \(\pm\) 4.90} & \multirow{2}{*}{\(-\)6.23\%} & \multirow{2}{*}{1.382} \\  & (Hz) & & & & \\ \hline \multirow{4}{*}{GCM} & Muscle activity & \multirow{2}{*}{\(-\)0.113 \(\pm\) 0.082} & \multirow{2}{*}{\(-\)0.019 \(\pm\) 0.024} & \multirow{2}{*}{\(-\)83.51\%} & \multirow{2}{*}{\(-\)2.754 \({}^{\ast}\)} \\  & (\%MVC) & & & & \\ \cline{1-1} \cline{2-5}  & Muscle fatigue & \multirow{2}{*}{\(-\)0.015 \(\pm\) 0.084} & \multirow{2}{*}{\(-\)0.025 \(\pm\) 0.119} & \multirow{2}{*}{\(-\)76.08\%} & \multirow{2}{*}{\(-\)2.197} \\  & (Hz) & & & & \\ \hline \end{tabular} RE, rectus femoris; ST, semitlinosus; TA, tibialis anterior; GCM, gastrocnemius; MA, muscle activity (%MVC); ME, muscle fatigue (Hz); \(\$\) mean \(\pm\) standard deviation; \({}^{\ast}\)\(p<0.05\); \({}^{\ast\ast}\)\(p<0.01\).  
\end{table}
Table 4: Results of average muscle activity and muscle fatigue of lower-extremity muscles during walking up stairs.  
\begin{table}
\begin{tabular}{c c c c c} \hline  & **No WIM** & **WIM** & **\% Difference** & **t-Value** \\ Oxygen uptake & \multirow{2}{*}{9.28 \(\pm\) 1.22 \({}^{\$}\)} & \multirow{2}{*}{8.55 \(\pm\) 1.55} & \multirow{2}{*}{\(-\)7.93\%} & \multirow{2}{*}{5.447 \({}^{\ast\ast\ast}\)} \\ (VO\({}_{2}\)/Kg) & & & & \\ \hline Heart rate (bpm) & 88.93 \(\pm\) 12.05 & 86.78 \(\pm\) 14.74 & \(-\)2.42\% & 1.647 \\ \hline EEM (kcal/min) & 3.47 \(\pm\) 0.40 & 3.21 \(\pm\) 0.48 & \(-\)7.39\% & 5.102 \({}^{\ast\ast\ast}\) \\ \hline Total EE (kcal) & 10.41 \(\pm\) 1.22 & 9.66 \(\pm\) 1.43 & \(-\)7.26\% & 5.636 \({}^{\ast\ast\ast}\) \\ \hline Net EEM & 2.42 \(\pm\) 0.33 & 2.16 \(\pm\) 0.42 & \(-\)10.59\% & 5.102 \({}^{\ast\ast\ast}\) \\ \hline EE, energy expenditure; EEM, energy expenditure per min; \({}^{\$}\) mean \(\pm\) standard deviation; \({}^{\ast\ast\ast}\)\(p<0.001\). & & & \\ \hline \end{tabular}
\end{table}
Table 3: Results of energy expenditure during 6 min treadmill walking.  
There was no significant difference in the stair-walking performance time for WIM use between the two conditions, excluding total EE, oxygen uptake (\(p\) < 0.05), heart rate (\(p\) < 0.01), EEM (\(p\) < 0.05), and the net EEMs (\(p\) < 0.01) all decreased.