## 3 Results
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & & & **PRE-CON** & **PRE-1** & **POST-1** & **POST-2** & **POST-3** & **POST-4** & **POST-5** & **POST-6** \\ \hline \multirow{3}{*}{Erector Spinea (RMS \%)} & STOOP & 40.6 & 39.1 & 41.4 & 41.4 & 42.3 & 39.6 & 39.9 & 42.4 \\  & & (12.4) & (12.4) & (11.8) & (8.7) & (12) & (10.4) & (10) & (10.4) \\  & SQUAT & 41.7 & 40.9 & 45 & 47.4 & 43.3 & 41.4 & 41.3 & 43.6 \\  & & (12.9) & (12.3) & (15) & (14) & (12.1) & (8.8) & (10.1) & (10.6) \\ \hline \multirow{3}{*}{Gluteus Maximus (RMS \%)} & STOOP * & 19.5 & 19.9 & 25.2 & 19.8 & 19.6 & 20.7 & 19.5 & 19.4 \\  & & (13.2) & (14.6) & (13.9) & (10.4) & (9.2) & (10.1) & (12.1) & (11) \\ \cline{1-1}  & & 19.5 & 21.4 & 27.2 & 22.7 & 22.4 & 23 & 21.7 & 21.4 \\  & & (11.6) & (12.5) & (12.2) & (11.3) & (10.2) & (9.9) & (10.8) & (9.8) \\ \hline \multirow{3}{*}{Obliques Externus (RMS \%)} & STOOP & 5 & 6.3 & 10.1 & 8.9 & 7.9 & 7.2 & 7.6 & 6.9 \\  & & (4.6) & (6.3) & (9.4) & (5.7) & (6.1) & (5.1) & (8.1) & (6.2) \\ \cline{1-1}  & & 6 & 5.3 & 7.1 & 6.7 & 6.6 & 6.6 & 6.4 & 6.8 \\ \cline{1-1}  & & (2.9) & (3.2) & (5) & (3.8) & (4.3) & (3.9) & (3.5) & (3.8) \\ \hline \multirow{3}{*}{Rectus Abdominis (RMS \%)} & STOOP & 3.1 & 2.8 & 2.6 & 3.4 & 2.8 & 2.6 & 3.1 & 3.6 \\ \cline{1-1}  & & (2.6) & (1.7) & (1.6) & (3.4) & (2.6) & (2.3) & (3.6) & (4.1) \\ \cline{1-1}  & & 2.1 & 2 & 1.9 & 2.2 & 1.9 & 1.8 & 1.8 & 2.3 \\ \cline{1-1}  & & (1.4) & (1.4) & (1.1) & (1.5) & (1.2) & (1.1) & (1) & (1.5) \\ \hline \multirow{3}{*}{Tensor Fascia (RMS \%)} & STOOP & 7.3 & 8.2 & 5.5 & 5 & 4.9 & 5.6 & 5.9 & 4.5 \\ \cline{1-1}  & & (7.9) & (13.3) & (3.2) & (3) & (2.6) & (3.1) & (3.8) & (3.1) \\ \cline{1-1}  & & 11.9 & 12.4 & 13.3 & 12.2 & 11.8 & 11.3 & 11.7 & 11.7 \\ \cline{1-1}  & & (12.0) & (11.7) & (13.2) & (13.1) & (12.7) & (12.2) & (11.9) & (12.6) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Median (interquartile range) of muscle activity (RMS) in STOOP and SQUAT in PRE-CON and over the familiarization protocol from PRE-1 to POST-6. * Statistical main effect of the familiarization protocol. nor from POST-6 (\(p\) = 0.5). Other NASA-TLX weights were not significantly influenced by the familiarization protocol. Pressure perceptions, evaluated through Likert scales, were influenced by the familiarization protocol (Figure 5 and Table 4). Statistical analyses showed a significant main effect of familiarization on knee perceived pressure for both STOOP (\(p\) < 0.001, W = 0.19) and SQUAT (\(p\) = 0.01, W = 0.21). For STOOP, pairwise comparisons revealed that perceived pressure in POST-1 and POST-2 was significantly higher than in POST-5 and POST-6 (\(p\) < 0.001). For SQUAT, this analysis revealed significantly higher perceived pressure in PRE-1 than in POST-4 to POST-6 (\(p\) < 0.01), as well as for POST-1 compared to POST-4 and POST-6 (\(p\) < 0.001). PRE-CON values were not assessed due to the obvious absence of pressure perception. Also, there was a significant main effect of familiarization on buttock perceived pressure for both STOOP (\(p\) < 0.001, W = 0.23) and SQUAT (\(p\) = 0.01, W = 0.13). For STOOP, pairwise comparisons revealed that buttocks perceived pressure was significantly higher in PRE-1 than in POST-4 to POST-6 (\(p\) \(\leq\) 0.001), and also significantly higher in POST-1 than in POST-5 and POST-6 (\(p\) < 0.001) and higher in POST-2 and POST-3 than in POST-6 (\(p\) \(\leq\) 0.001). For SQUAT, buttocks perceived pressure was significantly higher in PRE-1 than in POST-3 and POST-6 (\(p\) < 0.01). Then, there was a significant main effect of familiarization on armpit perceived pressure in STOOP (\(p\) = 0.01, W = 0.13; Table 4), but post-hoc tests could not tease out significant differences between sessions. Next, the statistical analysis showed a significant main effect of familiarization on trapezius pressure in STOOP (\(p\) = 0.009, W = 0.13), which was higher in PRE-1 than in POST-6 (\(p\) < 0.01).