## 3 Results  
The results of demographic and anthropometric data collection, the questionnaire and clinical studies are shown in Table 1. The pilots and the healthy volunteers did not differ significantly in demographic and anthropometric characteristics. The pilots conducted moderate physical activity (training; moderate stretching exercises, bicycling, swimming) with a frequency of about two times a week, similar to the healthy subjects who were mainly the office workers (N = 7) than physical workers (N = 8). Only one pilot reported the incidence of a weak trauma, requiring short-lasting conservative treatment which could not permanently influence the general health status on the day of examination. Pilots experienced 1711 h of flying the high-maneuvering aircraft at 7G over-loading, all of them had four catapulting trainings, on average. The intensity of pain with the occurrence onset at 1.7 years on average in the cervical and the lumbosacral region was rated as 1.4 on average on the 10-point VAS scale by pilots Table 1). The studies of sensory perception (FvF) did not reveal any symptoms of hypereesthesia or hypoaesthesia in the area of C2-S1 dermatomes on both sides. Neither the pilots nor the healthy volunteers complained of symptoms of pain or numbness in the distal areas of the upper and lower limbs on both sides. Based on the data from the questionnaire (Table 2), the pilots with a number of flying hours <2000 reported the symptom of spine pain with a 0.88 intensity on average, while the pilots with a number of flying hours >2000 scored 1.67 on average. The twice as high pain level in pilots with a number of flying hours >2000 was not related to the frequency of weekly activity; similarly, about 2 h in all studied pilots. Examples of the recordings from neurophysiological studies performed in one of the pilots in comparison to one of the control subjects are presented in Figure 3. Table 3 \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Variable** & **Pilots (N = 15)** &
\begin{tabular}{c} **Healthy Subjects** \\ **(N = 15) Control** \\ \end{tabular} & \(\boldsymbol{p}\) \\ \hline Age (years) & (25–48) 38.2 \(\pm\) 7.6 & (22–47) 35.6 \(\pm\) 6.9 & NS \\ Height (cm) & (171–189) 178.0 \(\pm\) 4.8 & (161–182) 173.3 \(\pm\) 5.9 & NS \\ Weight (kg) & (52–95) 76.4 \(\pm\) 9.5 & (50–95) 76.9 \(\pm\) 10.3 & NS \\ BMI & (20.2–36.2) 28.1 \(\pm\) 5.3 & (19–28.7) 25.1 \(\pm\) 2.6 & NS \\ Number of flying hours (all years) & (410–3100) 1711.7 \(\pm\) 861.9 & NA & \\ Average number of training & 4 & NA & \\ catapulting & 1/15 & 0 & \\ Traumas & 1/15 & 0 & \\ Conservative treatment & 1/15 & 0 & \\ Activity (days in a week) & (1–4) 1.9 \(\pm\) 0.4 & (1–4) 2.3 \(\pm\) 0.5 & NS \\ Spine pain VAS (0–10) & (0–3) 1.4 \(\pm\) 0.6 & (0–0) 0 & NS \\ Spine pain (since when, years) & (1–3) 1.7 \(\pm\) 0.8 & 0 & \\ Pain–upper extremity & 0/15 & 0/15 & \\ Pain–lower extremity & 0/15 & 0/15 & \\ Numbness in hands & 0/15 & 0/15 & \\ Numbness in legs & 0/15 & 0/15 & \\ Superficial sensory perception & 1 & 1 & \\ (FvF) & & & \\ \hline \hline \end{tabular} Abbreviations: NS—not significant; NA—not applicable; VAS—visual analogue scale score; FvF—0—decreased, 1—normal.  
\end{table} 
Table 1: Demographic and anthropometric properties, results of reports and clinical studies in pilots and healthy subjects. Ranges, median or mean values with standard deviations are presented. summarizes the most significant differences found in sEMG, ENG, and MEPs recordings in two studied groups of subjects. The mean amplitudes of sEMG recordings performed at rest (rEMG) in all participants never reached values \(\geq\)25 u, which proves no pathological symptoms of the increased muscle tension. The values of amplitudes of sEMG recordings during the attempt of maximal contraction (mcEMG) have been found to be significantly higher in all examined muscle groups in pilots at \(p\) = 0.02-0.04, pointing to the better ability of the muscle motor units for the contractile properties than in controls.