## 4 Discussions  
Based on the mean from the performed 72 measurement tests it was determined that the average maximum velocity \(v_{max}\) in a single propelling cycle with the activated anti-rollback system was 0.47 m/s and with the deactivated anti-rollback system it was 0.54 m/s. This results in a 13% decrease in velocity during ramp climbing with the activated anti-rollback system in relation to the ramp climbing with the deactivated anti-rollback system. In the event of the minimum velocity of the propelling cycle, the following values were recorded: 0.13 m/s for the activated anti-rollback system and 0.27 m/s for the deactivated anti-rollback system. This results in 52% decrease in velocity during ramp climbing with the activated anti-rollback system in relation to the ramp climbing with the deactivated anti-rollback system. When averaging the velocity of a single propelling cycle and then determining a mean for all the performed measurement tests, the results were as follows: 0.31 m/s for the activated anti-rollback \begin{table}
\begin{tabular}{l c c c c c c} \hline  & \multicolumn{2}{c}{**Triceps**Brachili _MA_} & \(\Delta\) & \multicolumn{2}{c}{**Extensor Caripi Radialis Longus _MA_} & \(\Delta\) \\  & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** \\ \cline{2-7}  & **ON** & **OFF** & & **ON** & **OFF** & \\ \hline Participant 1 & 51.30 & 65.37 & 21.52 & 87.72 & 93.86 & 6.54 \\ Participant 2 & 60.16 & 66.00 & 8.85 & 71.59 & 82.41 & 13.14 \\ Participant 3 & 53.10 & 63.84 & 16.84 & 33.12 & 33.41 & 0.86 \\ Participant 4 & 37.46 & 46.05 & 18.67 & 37.39 & 43.37 & 13.79 \\ Participant 5 & 55.71 & 45.94 & 21.27 & 19.05 & 29.18 & 34.69 \\ Participant 6 & 46.69 & 55.05 & 15.18 & 18.14 & 23.26 & 22.01 \\ Participant 7 & 33.15 & 35.63 & 6.96 & 15.07 & 20.76 & 27.42 \\ Participant 8 & 27.55 & 43.92 & 37.28 & 26.99 & 28.43 & 5.08 \\ \hline \end{tabular}
\end{table} 
Table 7: The comparison of the average muscle activity of triceps brachili and extensor carpi radialis longus for respective participants, where _MA_—muscle activity, ON—activated anti-rollback system, OFF—deactivated anti-rollback system, \(\Delta\)—a percentage difference between muscle activity measured with the activated anti-rollback system and the deactivated anti-rollback system. Figure 11: The diagrams of the average muscle activity for respective participants with the activated anti-rollback system (anti-rollback ON) and with the deactivated anti-rollback system (anti-rollback system OFF). Where: \(\Delta\)—a percentage difference between the muscle activity measured with the activated anti-rollback-system and with the deactivated anti-rollback-system. system and 0.42 m/s for the deactivated anti-rollback system. For this parameter, the decrease amounted to 26% during ramp climbing with the activated anti-rollback system. Despite this decrease of the average propelling cycle velocity with the activated anti-rollback system, a minor difference in the path distance in a single propelling cycle was observed. The decrease in the path distance in a single propelling cycle s equaling 7% with the activated anti-rollback system was determined. Moreover, during ramp climbing with the activated anti-rollback system, it was determined that the average increase in the propelling cycle duration time \(t_{cycle}\) was 1%. These observations indicate that the kinematics of the upper limb movement propelling the drive wheel did not change with the activated anti-rollback system in relation to the wheelchair without such modifications. This was confirmed by the analysis of the push phase share in the propelling cycle because an average value of the push phase share was the same for ramp climbing with the activated anti-rollback system and with the deactivated anti-rollback system. The differences described in the velocity values result only from supplying the propelling system with an additional element generating motion resistances.