Saskia Baltrusch

164 Chapter 6 3.3 Subjective Performance Participants perceived lifting, static forward bending and static 3 point kneeling as less difficult when wearing the SPEXOR exoskeleton compared to control condition (Figure 3a, p=0.008, p=0.002 and p=0.001, respectively). For the remaining tasks, the exoskeleton did not significantly change perceived task difficulty. We did not find a significant main effects of group or interaction effects with group on perceived task difficulty (Figure 3b). Figure 3a: Boxplots of change in perceived task difficulty for the various tasks. (The red/ green line represents the sample median. The distances between the tops and bottoms are the interquartile ranges. Whiskers show the min and max values, including outliers.) *Significant change in perceived task difficulty between exoskeleton (with) and control condition (without). Note that in this figure an increase represents a negative effect and a decrease a positive effect. Figure 3b: Difference in perceived task difficulty between control and exo condition in the subgroups healthy participants compared to participants with low- back pain.