## 3 Results
No differences in FI indexes recorded in the two groups of examined subjects were found, indicating no pathological changes in the recruitment of the motor units of neurogenic origin. Figure 3: Examples of electromyographic recordings ((**A**), sEMG) at rest (rEMG) and during the attempt of 5 s lasting maximal contraction (mcEMG), electroneurographical examinations ((**B**), ENG) and motor evoked potential recordings ((**C**), MEP) obtained in one of the healthy volunteers and in one pilot from the studied group for comparison. Calibration bars of amplitudes and time bases of recordings are the same for all sEMG, ENG and MEP recordings, subsequently. Results of the ENG studies in both groups of participants regarding the peripheral nerve impulses transmission in the motor fibers of median nerves and within C6 ventral roots bilaterally did not present clear-cut abnormalities in the parameters of M potentials (CMAP) amplitudes or recorded F wave frequencies. On the other hand, we have found significant (\(p=0.05\)-\(0.04\)) decreases in the parameters of amplitudes and increases in the latencies parameters of recorded M potentials following peroneal nerves stimulations, which may suggest the moderate changes of axonal and demyelinating nature. They were related to the decreases in frequencies of the recorded F waves (at \(p=0.05\)) suggesting the onset of abnormalities from the level of L4-L5 ventral roots. Data presented at the bottom of Table 3 regarding parameters of MEPs recordings following the stimulation of the spinal motor centers at C6, C7 neurones do not indicate significant differences between the pilots and the healthy subjects. Differences in parameters  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multicolumn{2}{c}{\ \begin{tabular}{c} **Type of Test** \\ **Recording Site** \\ **Stimulation Site** \\ \end{tabular}  } & \multicolumn{4}{c}{ \begin{tabular}{c} **Monets (Healthy Subjects)** \\ **Parameter** \\ \end{tabular}  } & \multicolumn{2}{c}{**Pilots**} & \multicolumn{2}{c}{**Pilots**} & \multicolumn{2}{c}{**Pilots**} \\ \cline{3-8} \multicolumn{2}{c}{} & \multirow{3}{*}{BIC} & \(\epsilon\)EMG (\(\mu\)V) & \(13.6\pm 3.5\) & \(15.7\pm 3.2\) & \(15.0\pm 1.9\) & \(14.3\pm 2.6\) & 0.06 & 0.07 \\  & & mcEMG (\(\mu\)V) & \(1500.0\pm 379.8\) & \(1435.7\pm 359.8\) & \(2842.9\pm 1233.9\) & \(2392.9\pm 1167.7\) & 0.02 \(\uparrow\) & 0.03 \(\uparrow\) \\  & & F1 & \(2.8\pm 0.4\) & \(2.8\pm 0.4\) & \(2.7\pm 0.5\) & \(2.7\pm 0.5\) & 0.06 & 0.06 \\ \cline{3-8} \multicolumn{2}{c}{} & \multirow{3}{*}{APB} & \(\epsilon\)EMG (\(\mu\)V) & \(16.4\pm 2.9\) & \(13.6\pm 2.9\) & \(13.6\pm 4.4\) & \(13.2\pm 4.4\) & 0.02 & 0.07 \\  & & mEMG (\(\mu\)V) & \(1557.1\pm 394.1\) & \(1664.3\pm 345.6\) & \(3057.1\pm 1080.8\) & \(2785.7\pm 1249.5\) & 0.01 \(\uparrow\) & 0.02 \(\uparrow\) \\  & & F1 & \(2.9\pm 0.3\) & \(2.9\pm 0.3\) & \(2.8\pm 0.6\) & \(2.9\pm 0.3\) & 0.1 & 0.12 \\ \cline{3-8} \multicolumn{2}{c}{} & \multirow{3}{*}{RECT} & \(\epsilon\)EMG (\(\mu\)V) & \(15.0\pm 3.3\) & \(13.9\pm 4.3\) & \(15.4\pm 1.2\) & \(15.4\pm 1.3\) & 0.07 & 0.06 \\  & & mEMG (\(\mu\)V) & \(1442.9\pm 145.0\) & \(1535.7\pm 183.6\) & \(2671.4\pm 1412.9\) & \(2392.9\pm 1310.1\) & 0.02 \(\uparrow\) & 0.04 \(\uparrow\) \\  & & F1 & \(2.7\pm 0.5\) & \(2.9\pm 0.3\) & \(2.8\pm 0.4\) & \(2.9\pm 0.3\) & 0.12 & 0.11 \\ \cline{3-8} \multicolumn{2}{c}{} & \multirow{3}{*}{EXT} & \(\epsilon\)EMG (\(\mu\)V) & \(16.1\pm 2.8\) & \(13.2\pm 2.4\) & \(17.1\pm 2.5\) & \(14.2\pm 4.5\) & 0.06 & 0.07 \\  & & mEMG (\(\mu\)V) & \(1449.9\pm 373.1\) & \(1070.1\pm 308.1\) & \(2907.1\pm 1602.4\) & \(2664.3\pm 1256.8\) & 0.02 \(\uparrow\) & 0.03 \(\uparrow\) \\  & & F1 & \(2.8\pm 0.4\) & \(2.9\pm 0.3\) & \(2.9\pm 0.3\) &of more amplitudes than latencies between pilots and controls have been found at \(p\) = 0.05-0.03, when MEPs induced oververtebrally excited L4 more than L5 spinal motoneurones and ventral roots and recordings were performed from the distal lower extremities muscles (see Figure 3C).