## 3 Results
### Supported Body Areas and Investigated Parameters  
Figure 3 illustrates that the parts of the body most commonly supported by occupational exoskeletons in the documents analyzed are: various parts of the spine (lumbar, trunk, and thorax) and the entire spine, as well as the lower and upper limbs. These parts of the body are also the most sensitive to MSDs. Some studies suggested that occupational exoskeletons have the potential to reduce the risk of developing MSDs in these locations, by providing support and reducing the load on the musculoskeletal system. About the 10% of the occupational exoskeletons investigated were tested in industrial facilities, while most of the applications were from laboratory studies. The factors analyzed in the documents investigated in the study are in Figure 4. In the articles analyzed, the topics that received the most attention, in order, are: user discomfort and perceived usability, muscle activation, kinematics, and metabolic consumption. These findings provide insight into the areas where research is most focused and, consequently, which factors are deemed most significant to those studying the interaction between exoskeletons and users. Muscle activation is a key metric because exoskeletons work by providing additional support to the wearer's muscles. Electromyography (EMG) is a technique used to measure and evaluate the electrical activity generated by the muscles during contraction. EMG is a useful method for assessing the success of exoskeletons in lowering muscle activation levels, which can indicate reduced physical strain on the user. It can also aid in identifying places where exoskeleton design and configuration may need to be changed to optimize their effects on muscle activation. The user's comfort and discomfort during exoskeleton use is particularly important to evaluate, since it might influence their willingness to continue using the device. To examine the impressions of users during and after the usage of occupational exoskeletons, interviews and questionnaires with both open-ended and closed-ended questions are frequently utilized. In particular, questionnaires and annotations of impressions during usage were the most commonly used approaches in the research examined in the present study. Questionnaires are extensively used because they allow for uniform data gathering and may be delivered to a large sample size with ease. Open-ended questions are frequently included in questionnaires to allow participants to offer more thorough feedback. Figure 3: Body areas supported by the occupational exoskeleton, and number of studies that investigated the use of an occupational exoskeletons supporting each specific body area. The methodologies adopted in the questionnaires to obtain users' subjective ratings include: the [PERSON]'s scale to assess the rate of perceived exertion [17]; the local perceived pressure to evaluate the musculoskeletal pressure of the parts of the body that are in contact with the exoskeleton [18]; the visual analog scale and the numeric rating scale to measure the pain intensity [19] and the pain severity [20]; the system usability scale to assess the perceived usability [21]; and the Likert scale to collect the level of agreement and disagreement of users on a symmetric agree-disagree scale for a series of statements [22]. Questionnaire are convenient and easy to administer, but they may suffer from response bias or may not capture the full range of experiences and perceptions of the user. On the other hand, annotations of perceptions during use provide more detailed and personalized feedback, but they may be time-consuming to analyze and may not be feasible for larger sample sizes. Overall, the choice of methodology for assessing personal perceptions about exoskeletons should be carefully considered based on the research question and the specific population being studied. Combining multiple methods may also provide a more comprehensive understanding of the user's experience with the exoskeleton.