Usability of the Upper Limb Risk Assessment (UPLIRA) Method for Assessing the Risk Factors of Upper Limb Disorders

It is important to design ergonomic methods or assessment with a high usability and good ergonomic features, so the method is easily adaptable to the task and the workplace environment. Usability is a measurement on how well the user can use that functionality. The study converged on testing the usability of the new tools for assessing ULDs namely as Upper Limb Risk Assessment (UPLIRA). The UPLIRA method was evaluated by 6 students (3 undergraduate students and 3 postgraduates students) from University Tun Hussein Onn Malaysia (UTHM) who are conducting research in ergonomic. From the feedback survey of UPLIRA method, the observers agree that the prototype of UPLIRA tool was applicable to workplace assessment for the wide range of jobs/task (mean 4.00, SD:0.632) with 83% percentage of agreement . They also indicate that UPLIRA method is quick to use (mean 3.67, SD:1.033) with percentage agreement of 67%. The scoring system and action level was rated as easy to understand (mean 3.67, SD:1.211) and (mean 4.17, SD:0.408). Conclusively, the UPLIRA method was rated as straightforward to use, applicable to wide range of tasks, and time saving as assessment can be completed within 10 minutes. In addition, the UPLIRA assessment covers an extensive range of physical, psychosocial, work organizational, and individual risk factors.


Introduction
Upper limb disorders (ULDs) are injury that affected the upper part of the body including neck, shoulders, elbows, wrists, and upper back [1]. ULDs correspondingly cause disability, absenteeism, pain, heavy financial costs among workers worldwide, and reduced productivity [2][3]. Prolonged exposure to risk factors at workplace may contribute to the occurrence of occupational health disorders and development of occupational diseases such as repetitive movements, awkward posture, forceful exertion, awkward posture, and vibration [3][4]. In addition, the previous study reported that psychological and individual factors such as gender, age, BMI, smoking, and anthropometry also play a role in the development of ULDs [5]. The psychosocial factors such as workload, job dissatisfaction, limited social support, time pressure and limited job control further increase the potential for the worker to get an upper limb disorders [5]. However, only a few studies have considered the multifactor association of job, individual, and psychosocial factors in assessing the prevalence of ULDs [6].
Pen and paper based observational methods are probably the most frequently used to evaluate physical workloads in order to identify hazards at workplace. The number of available methods are large, but no single method is suitable for all purposes. Since, different methods often focus on different exposures, it may be worth to combine several methods to perform a more comprehensive risk assessment [7]. The current techniques for assessing exposure to risk factors associated with ULDs includes Rapid Upper Limb Assessment (RULA) [8], Job Strain Index (JSI) [9], Occupational Repetitive Actions (OCRA) [10], Cumulative Trauma Disorders (CTD) [11], Loading on the Upper Body Assessment (LUBA) [12], Upper Limb Disorders (ULDs) Health and Safety Guide (HSG-60) [13], and Assessment of Repetitive Task (ART) [14]. From the objective for each tool, it can be concluded that the aim was to not entirely fixate on assessing the work-related upper limb disorders. Most of them only focused on general ergonomic risks [15].
It is substantial to design ergonomic methods or assessment with a high usability and good ergonomic features, so the method is adaptable to the task and the workplace environment. Usability measured the ability of a user to use that functionality [16]. In the study of [17][18] found that the usability of ART has the highest mean score. Meanwhile, the lowest rated method was the OCRA checklist. The OCRA checklist also required a relatively extensive period in average for assessment. This is probably because the ART tool is simpler as compared to OCRA checklist. Therefore, the main objective of this study is to test the usability of the new tools for assessing ULDs namely as Upper Limb Risk Assessment (UPLIRA).

Study Design Data Collected
The prototype was evaluated by 6 students (3 under graduate students and 3 postgraduates students) from University Tun Hussein Onn Malaysia (UTHM) who are conducting research in ergonomic. Firstly, the participants were given a brief discussion about the purpose of the tool, the applications of UPLIRA, the instructions, the scoring system, action level system, and exposure level. Then, all the participants were briefed on how to conduct an UPLIRA assessment for about 1 hour during the day. The video of 3 different tasks being performed such an operator in packaging section, a cashier, and an accountant was presented. After that, the participants made their assessment on each recorded task. The video was re-played to ensure that all observers could complete their assessment on that particular task. About 10 minutes were taken by the observers to evaluate each task.
After the observers completed all their assessment, they fill out the feedback survey questions to evaluate the usability of the UPLIRA method. The questionnaire comprises 3 parts; part 1 consists of 13 questions about the UPLIRA method such as , simple and quick operation, the clarity and conciseness of the instructions, the readability of the wordings, the clarity and conciseness of the pictures/illustrations , level of results interpretation of scoring system, understandability of the score for each items, understandability of the final score and action level applicability towards workplace assessment, applicability in wide range of jobs/tasks, valuable at works (cost effective) and valuable at works (provide a good basis for intervention proposals) as shown in Figure 1. These closed-ended questions were rate with five point Likert scale (1 = strongly disagree, 5 = strongly agree). Part 2 on the other hand consist of overall comments and suggestions for UPLIRA method and Part 3 consist of comments and suggestions for each part as shown in Figure 1 and 2.

Data Analysis
Statistical analysis was performed using Statistical Package for Social Sciences (SPSS) version 22. The feedback survey was presented as mean, standard deviation (SD) and percentage.

Results and Discussion
This section discussed the feedback for usability of UPLIRA tool, general comment, and suggestion for UPLIRA tool, and specific comments and suggestion for UPLIRA tool. From the result, the observers (n = 6) indicates that the prototype of UPLIRA tool was easy to use and straightforward (mean 3.60 SD:1.140), quick to use (mean 3.67 SD:1.033), instructions is clearly to read and understand (mean 3.17 SD:0.753), wordings is clearly to read and understand (mean 3.33 SD:0.816), pictures or illustrations is clearly to see and understand (mean 3.83 SD:0.753), scoring system is easy to interpret the results (mean 3.67 SD:1.211), score for each items is easy to interpret the results (mean 3.50 SD:1.049), final score is easy to understand (mean 3.67 SD:1.506), action level is easy to understand (mean 4.17 SD:0.408), applicable to workplace assessment (mean 4.00 SD:0.632), applicable to wide range of jobs/tasks (mean 4.17 SD:0.753), valuable at works which is cost effective (mean 4.17 SD:0.753), and finally valuable at works which provide a good basis for intervention proposals (mean 4.17 SD:0.753). Figure 1 tabulated the results of percentage feedback survey of usability from 6 observers (3 undergraduate students and 3 postgraduate students). Table 1 shows the observers rating of feedback surveys for usability of UPLIRA method.  Figure 1 shows the percentage for feedback survey on usability of UPLIRA method. All of the observers agreed and strongly agreed that UPLIRA method is easy to use and straightforward (60%), quick to use (67%), instructions is clearly to read and understand (83%), wordings is clearly to read and understand (50%), picture or illustrations is clearly to see and understand (67%), scoring system is easy to interpret the results (50%), score for each items is easy to understand (50%), final score is easy to understand (67%), action level is easy to understand (100%), applicable to workplace assessment (83%), applicable to wide range of jobs/tasks (83%), valuable at works which is cost effective (83%), and lastly valuable at works which provide a good basis for intervention proposals (83%). From the results, it is deduced that more than 50% of observers has either agreed or strongly agreed with the questions of the survey. From the feedback questionnaire about usability of the UPLIRA method for all participants (n = 6) using ratings (1 = strongly disagree to 5 = strongly agree), found that the action level is easy to understand with mean (mean 4.17 ± 0.408) with percentage of agree and strongly agree was 100%. This is because the final score is easy to understand that lead to choosing the suitable action level. The observers considered that these prototype is applicable to wide range of job/task (mean 4.17 ± 0.753), valuable at works (mean 4.17 ± 0.753), and provide a good basis intervention proposals (mean 4.17 ± 0.753) with percentage agreement of each was 83%. This is because the observers believe that the UPLIRA method can be used at different workstations. Unfortunately, the observers found that the instructions and wordings is not readable and understandable based on the relatively low score (mean 3.17 ± 0.753) and (mean 3.33 ± 0.816) with percentage of agreement of 83% and 50% respectively. This is because the observer found that the font is small and the color of figure and box of risk level is confusing. In addition, the observers found that the pictures or illustration is vague (mean 3.83 ± 0.753) and percentage agreement was 67%. The observers found that the picture and the motion is confusing. In other study found that it was difficult for observers to determine the specific angle solely by observation [19]. In addition, the observers found that the UPLIRA method is not really easy to understand, time consuming with the results (mean 3.60 ± 1.140) and (mean 3.67 ± 1.033) with percentage agreement 60% and 67% respectively. While for the scoring system and final score, the observers take more time to understand before they properly decide based on the score (mean 3.67 ± 1.211) and (mean 3.67 ± 1.506) with the percentage agreement was 50% and 67%. The observers stated that, the UPLIRA method is applicable to workplace assessment with the score (mean 4.00 ± 0.632) with percentage agreement of 83%.
Part 2 of feedback questions explored the general comments and suggestion for UPLIRA method. Most of the observers found that the left and right side is really confusing because it's not synchronized and the instructions should be explained appropriately for better understanding. Other than that, they believe that UPLIRA method can be a good reference for workplace improvement and good for ergonomic assessment especially in upper body. The UPLIRA method is confusing for the first-time user and the observers suggest that it need to be revised. Table 2 shows the summary of overall feedback comments from observers. i. It is a good for create a new method in the ergonomic assessment tool. ii. This will be one of the alternative to reduce the risk 4 i. The prototype need to be revised ii. Useful tool to use iii. It is difficult to use without any reference or user guide 5 i. The instructions is better in circle than cross (x) ii. The left and right side should be synchronized 6 i. The right and left side are confusing ii. The instruction not clear iii. The words in the score box is not clear iv. The angle line is not clear Table 3 shows the summary of suggestions from the observers. Some of the suggestions mentioned about using simple and short words for instruction, reducing the questions, adding more exposure level range, improving the range of angle motion, and minimizing the use of paper. The others mentioned about the technicality of the UPLIRA tool such as the keywords should be bold, increasing the size of risk level box, putting a degree (•) symbol in every classes of motion, and changing the color of the score box because the color of moderate box is same as the figure. Add more exposure level range iii.
Minimize the use of paper for scoring sheet 6 i. Put a degree (•) symbol in every classes of motion ii.
Make a short and simple instruction or used symbol iii.
The keywords should be bold iv.
Change the color of the score box v.
Minimize the used of paper vi.
Synchronized the left and right side Table 4 shows shows the summary of specific comments and suggestions for UPLIRA tool. This is the third part of feedback questions from UPLIRA tool. Most of the comments and suggestions are from Part 1 of the UPLIRA prototype which is physical risk factors items and some from psychosocial and individual risk factors. The repetition for every motion should be added in the UPLIRA tool. In addition, the illustration is not clear especially for wrist motion. Unclear definitions of postures can be a source of disagreement between the assessors [20]. Most of the questions comprises of choice (OR) options and it's confusing. Furthermore, the right (R) and left (L) side should be synchronized. In addition, the noise and lighting level should be used in numerical range instead of general value such as slow, loud, very loud. While for psychosocial risk factors, the observer believes that 'always' and 'often' have the similar meaning. They suggest using another word and reduce the questions and use only ones that are related to upper limb disorders. For individual risk factors, some of the questions is confusing. The observers also imply reducing the questions and only ask the questions related to upper limb disorders.  As the conclusion, the UPLIRA method was rated as it is straightforward to use, widely applicable, and time saving. In addition, the UPLIRA assessment covers an extensive range of physical, psychosocial, work organizational, and individual risk factors. Meanwhile, the disadvantages of UPLIRA assessment is that it is undoubtedly a complex method. Therefore, further refinements are required to render the UPLIRA to be a better assessment in evaluating work related ULDs