## 4 Discussion  
Changing PA when cycling an e-bike does not only influence the loading exerted by the upper leg muscles but also steer and seat loading. In general, the level of PA does not change the shape of an entire pattern. Significant differences are found, though only in certain phases of the pedal cycle. As most power is exerted in the downstroke phase (from 0 degrees to 150 degrees), most significant differences are found in the upper dead center and power phase. For all analyzed variables, the significant differences escalate in magnitude in function of the amount of pedal assistance. Furthermore, the variation increases in function of the amount of pedal assistance. This is in line with the literature as PA reduces the effort and an increased effort improves the symmetry of pedaling kinetics [34]. The phase in the pedal cycle is addressed from the perspective of the right pedal. The upper dead center and power phase of the right pedal are, respectively, the lower dead center and recovery phase of the left pedal. For this reason, seat and steer AVCs are expected to be symmetric between the two halves of the pedal cycle. Significant differences that are present in the upper dead center or power phase should also be present in, respectively, the lower dead center or the recovery phase. Though, as seen in the Section 3, this is not the case. Only the steer axial moment presents significant differences in opposing phases. When analyzing the AVCs, variation is significantly higher for the upper dead center and power phase of the left pedal, which hinders the significance of differences due to the level of pedal assistance. In total, 90% of the tested subjects are right-legged, utilizing their right leg as the leader and the left as the follower. Research states that increased pedaling effort demands a more stable technique and results in a reduced variability [35]. Therefore, differences due to PA should be visible in both opposing phases, though will not always be significant. Furthermore, multiple subjects are compared to each other, which increases the variation as each individual has his own cycling technique. Visual differences can be clinically relevant, even though they are not significantly relevant, and will be discussed in this section. Lateral loading originates from the pedaling movement and is predominantly generated in the downstroke phase. When generating the push on the pedals, the most comfortable power exertion direction is enforced, resulting in a small lateral component. PA reduces the power exertion during the push and, therefore, also the lateral component. In the power phase, a significant decrease in the lateral pedal force is observed due to PA (maximally \(-\)66.8%). Lateral seat loading patterns are induced by the pelvis movement. Towards the downstroke phase, the pelvis rotates internally and laterally, causing the hip to translate anteriorly and inferiorly. The movement is presented by the right leg in the first half of the pedal cycle and by the left leg in the second half of the pedal cycle, resulting in locally increasing lateral seat forces. PA significantly decreases the lateral seat forces maximally in the upper dead center (maximally \(-\)120.5%) followed by the power phase (maximally \(-\)116%). The decrease in the left leg is observable in the visual evaluation, though not significant due to high variation. Lateral steer-loading patterns are induced by trunk motion in the axial plane during pedaling. The trunk rotates medially towards the downstroke phase, generating a pull on the allied handle and a push on the opposing one, resulting in locally increasing lateral steer forces and axial moments. Increasing the levelof PA, decreases all steer axial moments significantly (maximally \(-69.5\%\) for the upper dead center, maximally \(-67.4\%\) for the power phase, maximally \(-50.6\%\) for the lower dead center and maximally \(-55.4\%\) for the recovery phase), the difference is the largest in the first half of the pedal cycle as the right leg is dominant.