## 3 Results  
### Participants  
Characteristics of the participants are shown in Table 1.  
No critical arrhythmias were detected during the exercise protocol, and VO\({}_{2}\) increased during the hybrid exercise when compared with the cycle ergometer exercise during the 4 min warm-up (10.9 \(\pm\) 1.9 mL/kg/min vs 9.4 \(\pm\) 1.0 mL/kg/min, respectively; \(p<0.05\) \begin{table}
\begin{tabular}{c c} \hline \hline
**Characteristics** & **Total (_n_ = 15, mean \(\pm\) SD)** \\ \hline Age (y) & 28.9 \(\pm\) 5.1 \\ Male (\%) & 10 (67\%) \\ Height (cm) & 166.7 \(\pm\) 7.5 \\ Weight (kg) & 64.7 \(\pm\) 11.8 \\ BMI (kg/m\({}^{2}\)) & 23.2 \(\pm\) 3.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Characteristics of participants. Figure 1: Protocol for the cardiopulmonary exercise test. (**a**) Each participant underwent a cycle ergometer exercise and (**b**) a hybrid of whole-body neuromuscular electrical stimulation with cycle ergometer exercise in a crossover study design. r = 0.72). During the hybrid exercise, the increase in VO2 was greater at the workload of AT (19.9 \(\pm\) 4.3 mL/kg/min vs 18.4 \(\pm\) 3.6 mL/kg/min, \(p\) \(<\) 0.05, r = 0.79); the increase in VO2 was greater up to the maximum load (Figure 2). Figure 2: (**A**) Comparison of VO2 between the cycle ergometer exercises and hybrid exercises (mean \(\pm\) SD). During the hybrid exercise, VO2 increased compared with the cycle ergometer exercise during the 4 min warm-up (_p_ \(<\) 0.05, r = 0.72). At the workload of anerobic threshold (AT) during the cycle ergometer exercise, the increase in VO2 was greater in the hybrid exercise (_p_ \(<\) 0.05, r = 0.79). (**B**) Serial changes in VO2 every minute during the cycle ergometer and hybrid exercises (mean \(\pm\) SE) \({}^{*}\)_p_ \(<\) 0.05. The metabolic responses at the respiratory compensation point of cycle ergometer exercise and hybrid exercise are shown in Table 2. Although there was no significant difference in exercise workload and ventilation at the respiratory compensation point between the two exercise programs, VCO\({}_{2}\) in the hybrid exercise at the respiratory compensation point was significantly higher than that in the cycle ergometer exercise (\(p<0.05\), r = 0.57). The results of the ex vivo microcirculatory evaluation are shown in Figure 3A. Whole blood passage time--as a parameter of blood fluidity--was significantly prolonged just after performing the cycle ergometer exercise when compared with the resting state (52.8 \(\pm\) 15.7 s to 112.6 \(\pm\) 66.0 s, respectively \(p<0.05\), r = 0.25). Similarly, the whole blood passage time was significantly prolonged just after the hybrid exercise when compared with the resting state (50.8 \(\pm\) 14.1 s to 123.8 \(\pm\) 63.1 s, respectively; \(p<0.001\), r = 0.41). There was no significant difference in the delta values for whole blood passage time (at rest and just after exercise) between the cycle ergometer and hybrid exercises (\(p=0.65\)). The results of the in vivo microcirculatory assessment are shown in Figure 3B,C The microvascular flow index and nailfold microvascular flow remained unchanged. Additionally, other in vivo values--including the total vessel density, perfused vessel density, and proportion of perfused vessels--remained unchanged after the hybrid, as well as cycle ergometer exercises. Still, the ex vivo values for blood fluidity demonstrated transient exacerbation. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Exercise Style** & **Load (W)** & **Minute Ventilation (L/mL)** & **VCO\({}_{2}\) (L/mL)** \\ \hline Cycle ergometer & 161.2 \(\pm\) 35.0 & 63.7 \(\pm\) 14.8 & 2117.6 \(\pm\) 463.3 \\ Hybrid & 162.1 \(\pm\) 33.1 & 71.4 \(\pm\) 16.3 & 2242.5 \(\pm\) 468.1 * \\ \hline \hline \end{tabular} Data are expressed as mean \(\pm\) SD. * \(p<0.05\) vs. cycle ergometer.  
\end{table} 
Table 2: Comparison of exercise load, minute ventilation, and VCO\({}_{2}\) at the respiratory compensation point.