# Skilled Workers' Perspectives on Utilizing a Passive Shoulder Exoskeleton in Construction
## 4 Discussion
### Study Limitations  
First, only one exoskeleton, the Hilti EXO-01, was trialed in our study. Hence, our findings may not be generalizable to all commercially available exoskeletons. However, it is worth noting that in another study, which assessed three different arm-support exoskeletons (i.e., Ottobock Paexo, Skelex 360, and Ekso EVO), the users had no preference between the three [31]. We evaluated the EXO-01 because it was specifically designed for use in construction and is supported by a recognized brand in the construction industry. Further, we believe that the liked and disliked exoskeleton qualities and features identified in this study are generalizable for the future development of exoskeletons for the construction industry.  
Second, it may be a concern that two days is insufficient for workers to trial the exoskeleton and accurately form their perceptions. However, field studies have demonstrated the consistency of workers' perception of an exoskeleton over longer durations of use and workers' ability to quickly assess its applicability to their work. For example, exoskeleton usage and perceptions remained consistent over 6 weeks and 18 months among plasters and automotive assembly operators, respectively [14; 17]. Bricklayers, in another field study trailing exoskeletons, identified that the exoskeleton was not suitable for their work after three days of wear [33]. The aforementioned literature and the consistency of our participants' responses support our belief that two days is sufficient for the participants to have accurately formed their perceptions on the value, barriers, and challenges associated with the product for its intermediate/immediate use. Despite this, we cannot rule out that workers' perceptions of the exoskeleton would change over time.  
Third, there may be a geographical limitation in the applicability of the results, as all study participants worked in Southern Ontario. Our data were collected throughout the year, and outdoor temperatures within the region can range from below 30 to over 30 degrees Celsius. During warmer months, participants mainly wore t-shirts, while more layers were worn in the colder months. The choice of clothing worn underneath the exoskeleton may impact the participants' perception of the exoskeleton's comfort, maneuverability, and thermal comfort [33].  
Lastly, sampling bias may be present in our study. We collected a convenience sample of construction workers who self-identified as someone who frequently performed overhead tasks. Hence, our participants were willing or open-minded enough to try the exoskeleton and participate in a research study. If a worker opted not to participate, we did not ask for them to provide a reason. We cannot determine whether they did not participate because they did not see a use for the exoskeleton or they could not commit to the study. Therefore, our sample may be biased toward those who wanted to try the exoskeleton. We cannot confirm how this impacted the results because there were participants who trialed the exoskeleton and did not like it. The inverse may also be true: those who did not try the exoskeleton may find value in it. We can only base our conclusion on the evidence that was collected.