Saskia Baltrusch

37 Chapter 2 bending [29,30]. In the long-term this reduction in muscle recruitment might lead to a reduction in back muscle capacity , due to the decreased demand on the back muscles, A long-term study on the effect of wearing an exoskeleton on muscle strength would be needed to deal with the patients’ concern. A requirement that derives from this argument is that an assistive device should be used temporarily and the level of support should be adjustable, as mentioned by the patients. Providing different levels of support allows the user to decide how much support is needed for certain tasks and how much work can still be performed by their trunk muscles. From the healthcare professionals’ perspective, disadvantages of using an assistive device would be confirming the patient’s disability, increasing vulnerability and potential dependency on the device. Given that low-back pain patients appear to often underestimate their own capabilities, an assistive device might only confirm their wrong self-perception. Trippolini et al. (2018) [31] showed that people suffering from low-back pain indeed have reduced self-efficacy. Low levels of perceived self-efficacy influence behavior in a way that people shy away from tasks they perceive as a threat with respect to their musculoskeletal disorder [32]. The focus group with patients confirmed that a change in movement behavior occurs due to fear of movement and fear of recurrent pain. Healthcare professionals even admitted partial responsibility as a result of wrong beliefs in the past that were communicated to low-back pain patients. Still, patients also confirmed that they believed to be supported in their daily activity tasks when wearing the device and indicated to be potentially more active with the exoskeleton, rather than feeling confirmed in their disability. Adapting movement behavior is a common way of low-back pain patients to deal with their pain and may consist of lowering physical activity [33] increasing trunk muscle co-contraction and reducing deep trunk muscle activity [34]. This leads to consequences such as decreased movement and motor variability, increased spinal loading [34] and detrimental effects, such as high cumulative load on intervertebral discs and stiffening of the trunk muscles [35]. Especially decreased motor control was mentioned by the healthcare professionals, who explained that low-back pain patients often show guarded movement. They therefore expressed their concern immobilizing patients with the exoskeleton, 2