## 6 Occupational Footwear Characteristics That Influence Biomechanics and Physiological Workload  
Previous studies included the testing of these work boots or combinations of them under acute and chronic simulated occupational workloads, assessing both biomechanical and physiological workloads, such as postural stability, gait, slips, and muscle activity, as well as heart rate, rate of perceived exertion (RPE), energy expenditure, oxygen consumption, and pain perception [8; 15; 37; 38; 39; 40; 41; 32; 35]. In order to assess the chronic effect these boot types have on postural stability, previous literature reported participants completing a simulated workload wearing each boot for four hours on separate days [8; 38; 42]. Results showed significantly greater postural stability with TB and SB compared to SR, with all three footwear leading to decrements in postural stability over the course of the workload [8]. Similarly acute workloads have also been reported to cause decrements in postural stability and lower extremity muscular exertion and muscle activity due to the physiological workloads [32; 42]. Regarding the physiological effects of footwear, the greater mass has been shown to increase energy expenditure, with every 100 g of increase in mass causing a 0.7-1.0% increase in energy expenditure [43]. Moreover, an increased rate of muscular fatigue and greater energy expenditure has been reported in firefighter boots, steel-toed work boots, and even military boots respectively [44; 45; 40], thus increasing the risk of falls due to decreased postural stability. Previous research has reported multiple findings revealing footwear with a lighter mass can significantly improve postural stability and energy expenditure over time [40; 41; 35; 42]. Furthermore, when comparing SB and TB, [PERSON] et al. [39] revealed no significant effect on heart rate, RPE, and pain perception. However, a significant difference in oxygen consumption and energy expenditure between footwear with SB was reported resulting in a 6.2% and 7.1% increase in horizontal and graded treadmill walking protocols, respectively [40]. A summary of the different biomechanics and physiology studies using the occupational footwear SB, TB and SR are presented in Table 2 followed by a summary of the findings with pictorial demonstrations of data collection of the different studies presented in Figure 2.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**No. **} & \multirow{2}{*}{**Study**} & \multirow{2}{*}{**Occupational Footwear**} & \multicolumn{2}{c}{**Human Performance Assessment**} & \multirow{2}{*}{**Variables Assessed**} & \multirow{2}{*}{**Workload**} & \multirow{2}{*}{**Conclusion**} \\  & & & & & & & \\ \hline \multirow{4}{*}{1} & \multirow{4}{*}{\ \begin{tabular}{c} [PERSON] et al., \\ _Footwear Science_, \\ 2014 [8] \\ \end{tabular}  } & \multirow{4}{*}{SB, TB, SR} & \multirow{4}{*}{ \begin{tabular}{c} Postural \\ stability using \\ sensory \\ organization \\ test. \\ \end{tabular}  } & Anterior–posterior & \multirow{4}{*}{Walking for 4 h in} & SB and TB had better \\  & & & & and medial–lateral & postural stability than \\  & & & & & & \\ \cline{1-1} \cline{3-5} \cline{