# Augmented Reality in a Lean Workplace at Smart Factories: A Case Study
## 6 Analysis and Discussion
### Results  
This research found that the prevalence of MSD among logistic workers in this case study is high, with 56% of participants reporting at least, one issue. The most commonly reported regions were shoulders (66%), lumbar region (66%) and neck (46%), according to the NMQ. When asked about physical effort, 78% mentioned handling heavy loads as the leading complaint. Additionally, processes such as the picking cycle in supermarkets (36%), tasks that require the worker to reach lower levels (20%) and repalletization in the incoming area (14%) presented a high physical demand for the workers. The highest levels of perceived strain were reported for activities involving heavy lifting, repeated movements, uncomfortable body positions, and material stored in hard-to-reach places. Furthermore, the cognitive effort was also a problem, due to workers having to find products and materials in a timely manner while being aware of any risks in their environment. When it came to the AR solutions proposed to lessen the risks identified in the RAES-Log methodology, the majority of workers had a favourable opinion and felt confident that they would be able to improve their working conditions and mitigate existing risks. In particular, they had trust in technologies such as exoskeleton technology (90%) and WWD (82%), which are likely to reduce physical strain and decrease the risk of work-related MSD. Regarding solutions for reducing cognitive workload, such as AAR and HMD, workers also felt that AR solutions could aid by reducing their mental strain throughout the working day. However, these technologies were seen as less important than those designed to decrease physical exertion, with acceptance ratings of 80% and 68%, respectively. Therefore, \begin{table}
\begin{tabular}{l c c c} \hline \hline \multicolumn{1}{c}{**Category**} & \multicolumn{2}{c}{**Parameters Assessed**} & \multicolumn{1}{c}{**Used Instruments**} \\ \hline \multirow{3}{*}{A. Workers’ characterization} & \(\bullet\) & Age & \\  & \(\bullet\) & Work experience & – \\  & \(\bullet\) & Tasks performed & \\ \hline \multirow{3}{*}{B. Musculoskeletal symptomatology} & \(\bullet\) & Diagnosed MSD & \\  & \(\bullet\) & Work-related occurrences & Numerical pain scale [85] \\  & \(\bullet\) & Classification of pain & \\ \hline \multirow{3}{*}{C. Perception of exertion} & \(\bullet\) & Assessment of physical exertion perceived by & \\  & \(\bullet\) & the workers; & Category Ratio-10 [86] \\  & \(\bullet\) & Identification of the most demanding tasks. & \\ \hline \multirow{3}{*}{D. Workers’ opinion and acceptance} & \(\bullet\) & Assessment of worker’s opinions about the & \\  & & possible AR solutions to implement in & Five-point Likert scale [87] \\ \cline{1-1}  & & workstations & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Summary of questionnaire structure, parameters assessed and used instruments [59]. workers are generally optimistic that AAR and HMD can help to reduce their cognitive effort and contribute to better working conditions. The global worker's opinion regarding the proposed AR solution is expressed in Figure 5, where is possible to understand that, for all the solutions, the majority of workers showed a positive judgment about these technologies to mitigate risks within their workplaces. Workers have the highest confidence in exoskeleton technology, which they feel can reduce the physical strain associated with handling heavy materials, a common complaint in the logistics industry. They also have a high level of trust in WWD, particularly in SMD supermarkets where workers carry heavy devices to scan the barcodes throughout the day. AR solutions such as AAR and HMD were seen as less important, but still provide an essential role in reducing cognitive workload and improving working conditions. Overall, workers were positive about the AR solutions put forth, showing enthusiasm and optimism about their potential to improve safety in their workplaces.