Saskia Baltrusch

223 Chapter 8 exoskeleton were similar to the main working tasks described by the employees. The task with the greatest decrease in self-efficacy (Sitting), was also mentioned in the focus groups as a potential problem. Furthermore, we observed increased self-efficacy in not only static, but also dynamic tasks. This can be explained by the qualitative data that describes the flexibility of the exoskeleton as an advantage to current static and inflexible external lifting devices. As an exoskeleton is worn around the body and therefore does not interfere with the workflow, luggage handlers and managers believed in a higher usability and ease of use compared to the current external/off- body systems. These external devices come with several limitations that limit their acceptability. Given the high workload of the employees and their feeling of responsibility, main issues that were mentioned by luggage handlers and managers were perceived slower task performance, and the static, inflexible nature of external devices, conflicting with the dynamic work of a luggage handler. Although being significant, it can be questioned whether an average change of 5 points in M-SFS score can influence people’s behaviour and increase their confidence in performing work related tasks. According to Trippolini et al. (2018) [29], the systematic measurement error for assessing self-efficacy in low-back pain people is around 12-16 points. This, however, is only the case for participants having a low self-efficacy (<60). Participants in the present study had considerably higher scores. Participants who had lowest base scores (40- 60) showed the highest increase in self-efficacy. Thus, the findings suggest, that wearing a passive trunk exoskeleton potentially increases self-efficacy in people with low-back pain, having a bigger effect if people show greater restrictions due to their low-back pain. This was confirmed in the focus groups, as employees state they are mostly open to wearing the exoskeleton if they suffer from low-back pain, hence when being restricted by their low back. An increase in self-efficacy implies increased confidence to succeed in a given task, implicating decreased low-back pain and disability [24]. This likely leads to higher participation level. Also, increased self-efficacy is expected to increase acceptability of the exoskeleton. When users perceive high self-efficacy regarding assistive technology, they will have a high adoption intention [33]. 8