## 3 Case Study: Evaluation of a Passive Back-Support Exoskeleton
### Stage II: Detailed Experimental Planning
#### 3.2.3 Questionnaires  
Two separate questionnaires, i.e., Questionnaire A and Questionnaire B, were developed to collect user perceptions. Questionnaire A (see Appendix A) serves as an introductory pre-test questionnaire, to be completed before the beginning of the test. It includes initial questions to measure users' familiarity with exoskeleton technology, their subjective opinions on these devices, and any prior experience using one. Users who have used an exoskeleton before are asked whether it was powered or passive, and which body part it supported (e.g., upper limbs, lower limbs, back). Additionally, Questionnaire A collects information about the participants, including their level of daily physical activity. For workers who regularly handle loads in their workplace, a set of questions investigates the average weight handled, the duration of the MMH activity, and the type of grip used. The  
Figure 5: The technological setup with the motion capture garment, sensorized baropodometric insoles, sensorized wristband, and passive back-support exoskeleton IX BACK AIR.  
primary objective of Questionnaire A is to better characterize the user sample. This allows for an assessment of how a person's physical activity level or experience in MMH may influence the overall evaluation of an occupational exoskeleton, both in terms of measured parameter variations and perceptions.  
Questionnaire B (see Appendix B) is designed to assess user perceptions after testing. It consists of 13 closed questions, where users rate their preferences on a scale from 1 to 5 for 11 questions. This questionnaire is divided into two parts: one to be completed after testing without the exoskeleton's use, and another after testing with the exoskeleton's use. The first part includes two questions: one assessing discomfort experienced in different body areas (e.g., neck, shoulders, upper limbs, back, legs, feet, and ankles), and another evaluating physical fatigue during specific task actions (e.g., maintaining an upright position, walking, bending the knees to lift a load, lifting a load without bending the knees). Users rate their discomfort and fatigue levels on a scale from 1 to 5. The second part, completed after testing with the exoskeleton's use, repeats these two questions to assess discomfort and physical fatigue. This allows for a comparison between responses after testing with and without wearing the exoskeleton. Specifically, one question investigates the Locally Perceived Pressure (LPP) in various contact areas between the exoskeleton and the human body, formulated using an LPP scale as proposed in [43]. The LPP scale was adapted to a 5-point scale to align the scores with other questions and enhance user questionnaire completion ease. Four usability questions were constructed using a five-point Likert scale [44] to evaluate the ease of wearing and using the exoskeleton, its comfort level, and any potential movement limitations introduced by the device. Two additional questions about usage intentions were formulated using a five-point Likert scale to collect information on how frequently users would use the exoskeleton and consider its implementation as an enhancement in their workplace. Lastly, users are asked about changes in their opinion regarding exoskeleton use and whether they perceive the exoskeleton as beneficial for their work activity.