Abstract
The prevalence of work-related musculoskeletal disorders (WMSD) continues to increase among office workers. Appropriate and easy quantification of the predisposing factors are essential in developing and implementing interventions to prevent WMSD in this population. This requires the use of assessment methods that provide elaborate estimation of workers’ exposure to identified risk factors rather than an abridged sample of their work routine. This study tests with five bank tellers the Ergonomic Assessment tool for Unstructured and unregulated Work (EAUW) originally developed to provide duration and frequency estimations of risk factors in informal, non-routine work. The goal of this case study is to demonstrate the EAUW’s usefulness and applicability in office ergonomics assessment. The results indicate that the principles governing the EAUW (real time coding of risk factors) are applicable to office work assessment and promises to provide detailed estimation of risk factors when compared to existing job analysis tools.
Introduction
Office ergonomics ensures workstations, tools and equipment are adapted to the task, workers’ anatomical and physical capabilities. This is an essential first step in characterizing and remedying likely causes of work-related musculoskeletal disorders (WMSD) in the office environment. Thus far, various ergonomic assessment tools have been designed to aid assessment of WMSD risk factors. Most existing office ergonomics assessment tools provide an abbreviated assessment and to some extent, are limited to the use of a single picture representing the most/worst assumed posture as the basis for the assessment (Hignett and McAtamney, 2000; McAtamney and Corlett, 1993).
The challenge with existing office assessment methods is that they do not provide a true reflection of the entire work situation and thus may under report some important risk factors that do not fall under the “most or worst” assumed working posture criteria and may miss duration or frequency estimations. This issue is further compounded in occupations with high variability in work tasks performed between different workers and for the same worker across multiple days (Acquah et al., 2020; Acquah et al., 2021).
Prior work by Acquah et al. (2020; 2021) has demonstrated the shortcomings of existing ergonomics exposure assessment tools for quantifying exposure to risk factors in unstructured and nonrepetitive type of work using informal e-waste recycling as an example (Acquah, 2020; Acquah et al., 2021). To overcome the limitations of previous observation-based assessment tools (e.g. REBA, RULA, QEC, and OWAS) the same research team developed and validated the Ergonomic Assessment Tool for Unstructured and Unregulated Work (EAUW) [Acquah et al., 2020]. This tool allows for the quantification of frequency and duration of physical exposures (awkward/non-neutral postures, forceful exertion, repetitive movements, contact stress, vibration and manual material handling) while accounting for the high variability in unstructured work environment (Acquah et al., 2020; Yeboah et al., 2022). The tool was shown to have very high inter- and intra-observer agreement (>0.8) and good criterion validity when compared to tools such as REBA, RULA, QEC, and OWAS (Acquah et al., 2020; Yeboah et al., 2022).
Although the EAUW was developed with informal, unstructured, and unregulated work in mind, the ergonomic principles governing the design and use of the tool may be applicable in other job context that also involve nonrepetitive and/or non-routine work such as office work. The aim of this investigation was to test the applicability of a modified version of the EAUW to office work assessment using the job of bank tellers as a case study.
Methods
Study design and setting
The study used a cross sectional study design and employed real time coding of direct work observation complemented by worker interviews to understand and analyse the various tasks performed by bank tellers and quantify relevant ergonomic exposures. The study received ethical approval from the Ethics and Protocol Review Committee (EPRC) of the School of Biomedical and Allied Health Sciences (SBAHS) of the University of Ghana. Permission was also sought from the management of the two banks involved in this study. All participants signed an informed consent form after the details of the study had been explained to them and they had agreed to participate in the study. The authors did not receive consent from management of the banks to take photographs or videos during the observation. Thus, the study relied on direct observations and real-time coding of exposure data on coding sheets for the EAUW.
Study participants and sampling method
A purposive sampling approach was used to select two banks out of eight banks from the banking square at the University of Ghana. Access Bank and Universal Merchant bank were selected based on the design of their banking hall which allows for easy observation of tasks being performed by workers. Ten (10) full-time workers were conveniently sampled from both sites as part of the job analysis phase of the study. Five (5) of these sampled workers, comprising of three (3) tellers from one bank and two (2) from the other were observed for exposure assessment using the EAUW. A total of one thousand three hundred and thirty-five (1335) observations were documented for the five (5) bank tellers in one working day over an approximately four-hour period. Multiple days assessments were not performed as bank tellers’ work do not vary significantly between days.
Instrument for data collection
A custom in-depth interview guide was developed to collect information on the various tasks performed by bank workers. The guide required participants to provide a step-by-step account of banking related tasks performed by tellers on a day-to-day basis.
The EAUW, which is an observation-based tool developed by Acquah et al (2020), was used to quantify physical risk exposures of bank tellers in real time. The tool assesses posture, forceful exertion, repetitive movement, contact stress, vibration, and manual material handling. The EAUW enables easy quantification of the frequency and intensity of physical exposures (Acquah et al., 2020; Yeboah et al., 2022) at 60 seconds interval for the entire duration of the assessment. This tool was validated in comparison with the Rapid Entire Body Assessment (REBA), Rapid Upper Limb Assessment (RULA), Quick Exposure Checklist (QEC) and Ovako Working Posture Analysis (OWASS) [Acquah et al., 2020; Yeboah et al., 2022].
Data collection procedures
Training of observers
Two observers were trained for two weeks on the use of the EAUW using training videos recorded for the initial development and validation of the EAUW. Observers were trained on the use of the coding guide and coding sheet that accompanied the EAUW. They were also given the opportunity to practice coding in real time at the banking hall to familiarise themselves with the modified version of the tool.
Task analysis and worker observations
The study procedures comprised of two parts: 1) a task analysis phase and 2) an observation-based job assessment phase.
The task analysis phase began with a walk-through observation at the banking hall to observe tasks performed by workers on a daily basis. This was done on two non-conservative working days and all observations documented in a field notebook. The walk-through observations were followed up with a brief interaction with staff in order to confirm the observed and identified tasks and to provide information on additional tasks performed by workers that might have been missed during the observation. Experienced bank workers were interviewed to provide a step-by-step account of activities performed on a normal workday. An in-depth interview guide aided questions being asked and responses were audio recorded and transcribed for analysis. The observation notes and interview responses were then used to develop a sequential and logical description of bank tellers daily work tasks.
Based on the identified tasks, the EAUW was modified for easy adaptability to the structured job tasks performed by bankers. Lifting, carrying, pushing/pulling and vibration included in the original EAUW were omitted since these were virtually inexistent in the work of bank tellers. Postures assessed included neck, trunk, upper limb, and lower limb. For the lower limb, three main working postures were considered (standing, walking, and sitting).
The pen and paper-based coding templates and guide of the EAUW was modified to reflect the changes indicated above. The modified template was pilot tested and subsequently used to assess bank tellers’ exposure to risk factors for at least 4 hours of their work shift.
Data analysis
All coded observations were recorded into Microsoft Excel. Proportions of time spent in each task and working posture were computed and tabulated.
Results
Task analysis
Ten (10) job tasks were identified among bank tellers. These included:
Interactions with customers / clients and co-workers
Typing or entering information into a desktop computer
Making and receiving calls on an office telephone
Writing and signing receipts, client forms and/or letters received by the bank
Stamping of receipts and other paperwork
Collection and counting of money (either paper notes or coins)
Giving out money or receipts or forms
Stapling of papers
Photocopying
Walking to and from co-worker’s workstation
The identified job tasks involved prolonged periods of sitting interspersed with occasional walking. Walking tasks included: walking to interact with clients or co-workers as well as walking to the photocopier to make copies of a document. Awkward sitting postures, high repetitive movements of the upper limb and the presence of contact stress from working surfaces were observed among workers.
EAUW exposure assessment
The observed Bank tellers spent 70% of their working time (WT) sitting. Sitting postures however, mostly involved neutral trunk postures (90% of WT). Non-neutral neck postures were present 33% of the WT. Banking tasks were done 82% of the time with hands above waist height and below shoulder height. Contact stress was present 42% of their WT. Typing [combination of force exertion and repetition] (26% of WT), writing [primarily repetition] (27% of WT) and counting money [repetition and some contact stress] (25% of WT) were frequently performed activities. The proportion of working time spent in various working postures as well as time spent performing work tasks are presented in Table 1. The numerical results correspond to cumulative number of times the 5 workers observed were exposed to each risk factor.
Ergonomic risk exposures among bank tellers.
Discussion
This study shows that the application of the EAUW for the assessment of office work provides a detailed analysis of tasks and their relationship with established risk factors. The adaptation of the EAUW was based on a necessary preliminary task analysis to select the relevant risk factors and, sampling of observations, which then facilitated the application of the real time analysis. Hence it is assumed that this procedure can be used to adapt this assessment tool to different jobs in order to obtain in real time a coding of the risk factors. The initial task analysis is an essential phase for the modification/adaptation of the tool. A similar approach (Acquah, 2020; Acquah et al., 2019) was adopted by the developers of the EAUW during the formative process of the tool.
The EAUW assessment of risks among bank tellers revealed prolonged sitting, awkward neck postures and high repetitive movements as predominant risk factors. These risk factors are known to contribute to the development of WMSDs in various working populations (Kasaw et al., 2020; Naqvi et al., 2013) and are associated with neck and back pain, which are the cause of the most prevalent WMSDs reported among bankers (Kasaw et al., 2020). Prolonged sitting may be a source of fatigue leading to psychosocial stress. Intermittent standing, sitting, and walking at work reduces fatigue (Garcia et al., 2020), musculoskeletal discomfort and improves productivity (Thorp et al. 2014). The small amount of time spent walking at work is indicative of high sedentary work lifestyle which is a known risk factor for various chronic diseases (Bauman et al., 2013; Chen et al., 2009; Freak-Poli et al., 2011).
It is worth noting from the present study that typing formed an essential part of the daily tasks. Hence, the majority of the working time was spent sitting. However, the neck and trunk were often in a neutral position. These adequate postures may be resulting from an ergonomic workstation design; however, workstations were not evaluated. Nevertheless, the prolonged time spent interacting with computer screens could be a concern for the development of computer vision syndrome (Sen and Richardson, 2007).
Awkward neck and trunk postures reported in this study were essentially observed during writing and signing tasks, which were often accomplished with pen and paper on a non-adjustable desk. This work condition induced the posture. In addition, photocopy machines located at a low height on tellers working desk also required significant trunk and neck flexions.
High repetitive movements primarily derived from typing, writing/signing forms and money counting trigger the development of carpal tunnel syndrome (Wærsted et al., 2010). Stamping and stapling of documents although occurred multiple times and required considerable amount of forceful exertion was not performed for prolonged durations of tellers’ shift compared to the above manual activities. That notwithstanding, the repetitive movement and moderate to high force exertion associated with stamping and stapling tasks contribute to cumulative effects for upper limb WMSDs.
Overall, the modified EAUW is able to provide a detailed estimation of exposure to key risk factors in office work environment. The frequency and proportion of working time spent in various exposures can be associated with specific tasks. The assessment is based on a significant duration to adequately characterise exposures and their sequence, which may not be the case for most usual tools designed for job analysis (e.g., REBA, RULA, QEC, and OWAS). In addition, classic tools that emphasize “rapid” assessments tend to quantify exposures for the most frequently performed tasks or the most awkward posture assumed during work rather than a focus on the entire work. This may limit the data and information on other possible work scenarios which may also contribute to WMSD.
The main advantage of the EAUW is the ability to provide detailed assessment of ergonomic exposures in highly variable context and examine the association of risks with specific tasks. In addition, the present study supports the flexibility/adaptability of the tool for various conditions, including unstructured work, which overcomes a limitation of tools that were designed for the assessment of structured, regular, repetitive work.
Limitation
While a preliminary study with a relatively small sample, the focus was on determining the feasibility for using the EAUW in an office setting. One key limitation of the present study is that it does not compare the modified version of the EAUW directly with existing office ergonomic assessment tools to determine its criterion validity. However, this is the focus of a subsequent study.
Conclusion
Using a thorough task analysis and a detailed understanding of the specific work content, this study demonstrated the applicability of the EAUW with modifications for assessing ergonomic exposures in various office work setting.
Footnotes
Acknowledgements
Author AAA received funding from the National Institute of Health Fogarty fellowship 2022/2023 and Building a New Generation of Academics in Africa (BANGA-Africa) project (funded by the Carnegie Corporation of New York). We acknowledge the hard work of Miss Fridaus Abdul Samed a Research Assistant that supported research activities on this project.
