Saskia Baltrusch

156 Chapter 6 walking, which might reduce the use of this devices in working places that require substantial walking in between lifting and load handling tasks [16]. Recently, a new exoskeleton called SPEXOR 1 was developed with the aim to improve biomechanical support and overcome the limitations of available systems [17]. Pilot testing, to assess the effect of the exoskeleton on functional performance and user satisfaction in a range of working tasks, revealed encouraging outcomes. Users perceived several tasks as less difficult when wearing the exoskeleton and reported low interference with the actual task. However, sample size was small (n=3) and results could not be generalized. In this study, we therefore assessed the effect of wearing the SPEXOR exoskeleton on functional performance in a larger group of participants working in load-handling professions. We included potential end-users in our study population, to enhance generalizability to companies that may need such assistive devices. Moreover, we included employees with and without a history of low-back pain, to assess whether the results differ between the two groups, and hence to explore the application of the exoskeleton as prevention and/or pain management intervention. 2 Methods 2.1 Passive spinal exoskeleton In this study, we tested the passive SPEXOR exoskeleton, which is described in more detail in Näf et al. (2018) [17]. To reduce the peak and cumulative load on the lower back, the exoskeleton generates torques by two in-series connected passive actuators: a pair of hip actuators with misalignment compensation mechanism and an elastic spinal module (Figure 1a and 1b). The support torque generated at the hip is manually adjustable, by setting pretension of the springs in the hip actuator. The stiffness of the spinal module can be adjusted by adapting the thickness and number of the carbon fiber beams. The hip actuators are designed to be continuously adjustable between 10 Nm and 30 Nm peak output torque per side and up to 60 Nm in total (both sides). Current models of the spinal module can theoretically generate peak torques of up to 1 Spinal Exoskeleton for Low Back Pain Prevention and Vocational Reintegration