## 3 Results
### Eeg
#### 3.2.2 Beta PSD  
Significant differences in beta PSD were observed between the two protocols in the central scalp zone (\(p\) < 0.001) and TP (\(p\) = 0.027), but not in the frontal or parietal zones (all \(p\) > 0.05) (Table 2). Protocol differences occurred at 80% (\(p\) = 0.028) and 100% (\(p\) = 0.044) of the test duration (Figure 2). Within the IET protocol, beta power increased significantly from 60% to 80% (\(p\) = 0.006), with no significant change from 80% to 100% (\(p\) = 0.069). Similarly, within the SPV protocol, beta power differed from 60% to 80% (\(p\) = 0.048), but not from 80% to 100% (\(p\) = 0.733) (Figure 2).  
Unlike cadence, which was consistently higher in the SPV protocol than in the IET protocol, EEG responses were greater in the IET only towards the end of the tests (after 80% of the time to exhaustion) (Figure 2). Additionally, a significant main effect was observed for the time (\(F\) = 7.73, \(p\) < 0.001) and the condition (\(F\) = 6.32, \(p\) = 0.014) in the central scalp zone, although no significant interaction between the time and the condition was found.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Variable** & **IET** & **SPV** & \(p\) \\ \hline Central \(\alpha\) & 2.03 \(\pm\) 1.6 & 1.92 \(\pm\) 1.1 & 0.856 \\ Frontal \(\alpha\) & 1.80 \(\pm\) 1.2 & 1.72 \(\pm\) 1.0 & 0.856 \\ Parietal \(\alpha\) & 1.83 \(\pm\) 1.3 & 1.74 \(\pm\) 0.8 & 0.579 \\ TP \(\alpha\) & 1.83 \(\pm\) 1.3 & 1.75 \(\pm\) 0.9 & 0.587 \\ Central \(\beta\) & 1.65 \(\pm\) 0.9 & 1.33 \(\pm\) 0.8 & **<0.001** \\ Frontal \(\beta\) & 1.54 \(\pm\) 0.7 & 1.49 \(\pm\) 0.7 & 0.309 \\ Parietal \(\beta\) & 1.63 \(\pm\) 0.8 & 1.57 \(\pm\) 0.8 & 0.274 \\ TP \(\beta\) & 1.58 \(\pm\) 0.8 & 1.46 \(\pm\) 0.7 & **0.027** \\ Central \(\alpha\)/\(\beta\) ratio & 0.99 \(\pm\) 0.7 & 0.87 \(\pm\) 0.9 & 0.122 \\ Frontal \(\alpha\)/\(\beta\) ratio & 1.16 \(\pm\) 0.6 & 1.12 \(\pm\) 0.6 & 0.422 \\ Parietal \(\alpha\)/\(\beta\) ratio & 0.81 \(\pm\) 0.5 & 0.84 \(\pm\) 0.6 & 0.618 \\ TP \(\alpha\)/\(\beta\) ratio & 1.01 \(\pm\) 0.6 & 0.96 \(\pm\) 0.5 & 0.310 \\ \hline \end{tabular} Note: central, frontal, and parietal scalp zones are assessed for both alpha and beta bands, along with the alpha/beta (\(\alpha\)/\(\beta\)) ratio and total power (TP). Values are expressed as a percentage of baseline EEG measures. The value in bold indicates a statistically significant difference between the two tests (\(p\) < 0.05). Abbreviations: IET = incremental exercise test, SPV = self-paced VO\({}_{2}\)max test, \(\alpha\) = alpha, \(\beta\) = beta, \(\alpha\)/\(\beta\) = alpha/beta ratio, TP = total power.  
\end{table}
Table 2: Comparison of EEG alpha and beta power spectral densities between the incremental exercise test and the self-paced VO\({}_{2}\)max test.  
Figure 2: Comparison of changes in beta power spectral density in the central brain scalp zone during the incremental exercise test (IET) and the self-paced VO\({}_{2}\)max (SPV) test. The IET data are represented by the blue curve, and the SPV data are shown by the orange curve. The error bars are color-coded to match the corresponding condition (blue for IET and orange for SPV) to enhance the visual distinction between the two tests. Significant differences (\(p\) < 0.05) between the two tests are marked with asterisks (*), and differences between previous steps within the same test are indicated by daggers (\(\dagger\)).