https://orcid.org/0000-0002-8510-1980
Figures
Abstract
The construction industry is recognized as one of the most hazardous industries globally due to the dynamic on site activities and labour-intensive characteristics. The construction tasks are physically and cognitively demanding therefore the construction workers are prone to work fatigue which compromises safety performance. The evaluation of fit for duty, or fitness for work (FFW) aims to determine if workers are at risk of adverse impacts of ill-health, injury or accidents. This systematic review aimed to critically summarize up-to-date measures and evaluation tools that were employed to monitor work fitness or fatigue specifically among construction workers. Adhering with the PRISMA protocol, three databases were searched from the inception to 2022, with a total combination of 37 keywords, concluding to the selection of 20 relevant articles. The Mixed Method Appraisal Tool (MMAT) was used as the guide for the study appraisal. A total of 20 articles were reviewed, published from 2008–2022. Majority of the studies employed experimental design. The review identified the subjective evaluation scales and objective measurement tool. The subjective self-response questionnaires can be categorized into single dimension or multidimension covering both physical and mental fitness; whereas the objective measurement tool can be categorized into physiological metrics, physical and cognitive performance measure. The available scientific evidence has raised the relevant issues for on-site practicality and potentially guide the formulation of evidence-based guidelines for the FFW assessment in the construction industry.
Citation: Heng PP, Mohd Yusoff H, Hod R (2024) Individual evaluation of fatigue at work to enhance the safety performance in the construction industry: A systematic review. PLoS ONE 19(2): e0287892. https://doi.org/10.1371/journal.pone.0287892
Editor: Caio Bezerra Souto Maior, Federal University of Pernambuco: Universidade Federal de Pernambuco, BRAZIL
Received: April 6, 2023; Accepted: June 14, 2023; Published: February 7, 2024
Copyright: © 2024 Heng et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the paper and its Supporting Information files.
Funding: The author(s) received no specific funding for this work.
Competing interests: The authors have declared that no competing interests exist.
1. Introduction
The Fitness for Work (FFW), or “fit for duty” evaluation is a comprehensive functional assessment of a worker’s capacity to perform work tasks without jeopardising their own or others’ occupational health and safety [1]. The assessment aims to identify if workers are not fit for work due to the risk of adverse impacts of ill-health, injury, accidents or fatality [2]. The construction industry represents high risk for workers’ safety compared to other industries, due to its dynamics on site activities and complex settings; with labor-intensive characteristics [3, 4]. The scaffolders, steel fixers, form workers, electrician plumbers, concreters and other manual handling labourer are often categorized as workers with physically demanding and exhausting job that are prone to work fatigue [5, 6]. The overextended fatigue is highly associated with human error [7]. Construction tasks requires sequential procedural steps and an optimum level of alertness [8]. Certain functional fitness requirements for performing construction jobs, such as postural stability, balancing, muscle strength and endurance, and cognitive impairment, are difficult to be noticed, identified, measured, and reported [9]. A reduced physical capabilities and lapse in memory may therefore compromise the task performance, turning the routine task into hazardous task.
Globally, as high as 6,000 death among workers due to construction accidents were estimated annually [10]; with a major proportion (80%) reported due to individual attribute [11–13]. Occupational accidents result in devastating socioeconomic consequences because, in addition to causing physical and mental disability, fatal accidents have significant personal, societal, and financial costs [14]. Conventionally, passive safety counter measures have been undertaken in the prevention of construction accidents, including the on-site precautionary measures of Personal Fall Arrest Systems, guardrails, safety nets, harness, workers’ training in accordance with safety regulations, and task redesign. However. the overemphasize of technical and managerial factors rather than individual attributes such as fatigue, did not improve the construction accidents statistics substantially [15]. Counter measures to tackle the individual attributes such as work fatigue should therefore be explored and promoted. When workers are in the state of physical and cognitive degradation, their information processing ability is significantly reduced followed by a cascade of effects, such as diminished attentiveness [16], decrease reaction time in response to stimuli [17, 18]. This compromises decision-making abilities, as a result, triggers unsafe behavior [19], disrupts the safety of the workplace hence resulting in errors, risky conduct, injury, and mortality [16]. Fang et al. [20] while demonstrating the relationship between work fatigue level and safety performance, reported that workers were more likely to involve in errors and accidents when they were less fit for performance.
Fatigue at work evaluation should be tailored to the functional capacity requirements and risks of the job. In other words, the scope of assessment is customized and varies between occupation and job task [26, 31]. It was frequently evaluated among certain occupational groups including the army [21], healthcare providers [22], air crews [23], drivers [24] and factory workers [25]. On the other hand, Serra et al. (2007) in a critical review reported majority of the functional fitness assessment tools applied to individual worker were laboratory diagnostic tests which are invasive and time consuming [26]. Some of the examples of these assessment tools are urine drug screening test among drivers [27]; obesity and cardiovascular risk screening among the firefighters [28]; lung function assessment among miners [29], muscular strength, core stability, flexibility and balance among the astronaut’s crops [30].
The aggressive pace and rhythm at construction site can be super sensitive to the movement deceleration, in comparison to other works in relatively stable environment such as manufacturing and transportation industry. The FFW assessment must be tailored to the job function and work scenario [31, 32]. Those assessment tools employed in other industries might not be appropriately applied to the construction workers. Therefore, present critical review aims to systematically summarize various parameters used to measure physiological and psychological changes related to fitness and fatigue among construction workers and the potential evaluation tools that can be used to monitor work fitness capacity. Additionally, the type, scope and potential challenge of the worker-oriented measures will be discussed with the provision of future research directions in order to achieve the International Labour Organization’s aim of zero harm in the occupational setting.
2. Materials and methods
2.1. Formulation of research question
This review employed a systematic approach to an extensive search on relevant articles, followed by critical appraisal of the work fitness measures among the construction workers, as well as the encapsulation the type, scope and challenges of each FFW assessment tool. The relevant research question was formulated based on the three major concept in the PICO approach, namely: Population or Problem (construction workers), Interest (assessment tool or instrument), and Context/Outcome (fit for duty/fatigue) [33], which have guided the synthesis of the main research question ‘What are the potential assessment tools used to evaluate fitness for duty and monitor work fitness capacity among the construction workers in order to minimize the risk of work-related ill-health and injury?
2.2. Search strategy
The literature search was conducted in December 2022. Three databases were included, namely Scopus, PubMed and Web of Science. The 3 groups of keywords used for the searching of relevant articles are shown in Table 1. The combination of all groups of keywords using “AND” has produced a total of 295 papers, from the three databases. (Fig 1).
2.3. Selection criteria
Articles were selected based on specific inclusion criteria of: (1) original research; (2) written in English; (3) observational and experimental study relevant to the research question. The article was excluded if the outcomes related to fitness for work evaluation were not reported and not occupational related. Other exclusion criteria are: animals’ studies, review articles, case reports, newsletters, commentaries, conference proceedings, and grey literature.
2.4. Screening for eligibility and data extraction
All online search results (n = 295) were exported into EndNote 20.1, and duplicates were removed (n = 171). For the remaining 124 articles, abstract was read if uncertainties raised in the title. Two reviewers completed the screening of titles and abstracts and 55 non-relevant articles were removed, while the remaining articles were retrieved of full text (n = 69). There were 23 articles cannot be retrieved, leaving 46 articles for full-text assessment and eligibility screening. The relevant full-text articles were reviewed by the two independent reviewers. Any disputes or discrepancy between the two reviewers were resolved by the third reviewer. At the screening phase, all articles were compared against a pre-determined set of inclusion and exclusion criteria. The articles were considered eligible only if the study population was specific among the construction industry; and the outcome variable focus on the objective or subjective or combined assessment tool in order to evaluate “fitness for duty” in the perspective of physical or cognitive capacity. As a result, a total of 26 articles were excluded as the study were not occupational related, focused on occupations other than construction industry, irrelevant measure of pathological fatigue or chronic fatigue syndrome. Subsequently, the 20 remaining articles proceeded for data extraction including authors/year, country, population, study design, sample size, assessment tool (subjective or objective or combined), scope of evaluation (physical or cognitive fitness), results, strength or potential challenges.
2.5. Quality appraisal
Quality appraisal was conducted using the Mixed Method Appraisal Tool (MMAT) [34]. The MMAT is a critical appraisal tool developed to appraise methodology quality of five types of studies, namely qualitative studies, randomized control trials, non-randomized studies, quantitative descriptive study, and mixed methods study in a review article. The assessment based on five main criteria: sampling strategy relevant to address the research question; sample representative of the target population; measurements appropriateness; the risk of non-response and appropriateness of statistical analysis. The scores of qualities were reported as an overall score (5*****/100% quality criteria met; 4****/80% quality criteria met; 3***/60% quality criteria met; 2**/40% quality criteria met; 1*/20% quality criteria met) (S1 Appendix).
3. Results
There was a total of 20 articles reviewed in this study. The descriptive summary on characteristics of all included articles, including year of publication, study location and study design are tabulated in Table 2. The review articles were published from 2008 to 2022; one in 2018, two in 2009, two in 2014, three in 2015, three in 2017, four in 2018, two in 2020, two in 2021, one in 2022. Most of the studies were conducted in Asia: Taiwan (n = 4) [35–38], Hong Kong (n = 3) [39–41], India (n = 2) [42, 43], Korea (n = 1) [44], China (n = 1) [20]; followed by United States(n = 3) [32, 45, 46], Brazil (n = 2) [7, 47], and one article each for New England [8], Poland [48], Iran [49] and Chile [50]. Two-fifth of the studies (n = 8) employed experimental design in which three used simulated construction tasks. Another two-fifth (n = 8) employed cross-sectional design, while three employed longitudinal time series design and only one with case control design. The objectives, study population, details of assessment tool and research findings of all studies were summarized in Table 3.
The subsequent systematic analysis identified two main types of fatigue assessment tool, namely the subjective scale and objective measurement. The subjective evaluation tool included self-response or self-administered survey, which was further categorized based on the dimension they measured, namely physical fatigue; or the combination of multidimensional fatigue comprised of physical and mental domains. The Borg scale [36, 40, 41, 45] for the perceived fatigue based on efforts for exertion and the Baecke questionnaire [48] were used to evaluate solely on physical fatigue. On the other hand, validated questionnaire like Work Ability Index (WBI) [47, 49], Subjective fatigue symptoms RCIF scale [35, 37], Fatigue Assessment Scale for Construction Workers (FASCW) [7, 20, 37], Self-reported physical fatigue, physical and cognitive function and Swedish Occupational Fatigue Inventory (SOFI) [44, 46] were able to evaluate both physical and mental fatigue. For the objective measurement tool, it was further categorized based on the performance measure that the tool is able to assess, namely (i) physiological metrics of calf circumference [35, 37], blood pressure [35, 42], heart rate [7, 35–38, 40, 42, 45], oxygen consumption [36, 41], skin thermoregulation [40, 45] and electrical brain activity [38, 45, 46],(ii) physical performance measure of stability test of one leg standing test with eyes closed and opened [48], static balance test [39], core strength and endurance [43], lower limb flexibility [43], muscle strength test (pinch, grip, back) [35, 37, 43]; and (iii) cognitive performance measure of personal computer version of the Psychomotor Vigilance Test (PC-PVT) [46, 50] and critical flicker fusion [35]. The type, scope and challenges of the evaluation tool were illustrated in Table 4.
4. Discussion
The term “Fit to Work” correlates with work performance. It refers to the physical and mental wellbeing of the workers and their ability to fit well with the job task especially the high-risk work. Unfit for work has been recognized as a consequence of fatigue which can trigger unsafe behavior [51], lead to work error therefore leaving an impact on the safety and increase the likelihood of occupational accidents [19]. The scientific literatures have categorized causes of construction accidents into technical factors, environmental factors, human factors and organizational factors [52]. The technical errors arisen from deficiencies in the plant, equipment, tools or materials handling system such as insecure structure design. Human factors have been highlighted as the main culprit leading to construction accidents which is strongly associated with the individual fitness for work level that could be influenced by fatigue [53]. Human factor analysis further revealed that workers’ unsafe behaviour, violation of the safety rules. experience, PPE practices; are among the attributes that were caused by work fatigue. Fatigue is identified as an influencing factor for the applied capability task demands mismatch which may result in work error. In other words, fatigue may reduce the overall capability, so as to increase the probability of errors term [20].
Construction workers have high level of physical and cognitive demand as a result of an overextended work activity, therefore are prone to fatigue and safety performance degradation [8]. The work fitness assessment can be a huge challenge. Relevant indicators like postural stability, balancing, muscular fatigue, cognitive degradation is typically difficult to be self-recognized [9]. The unfit state is mostly underreported due to the job security issue [18] hence may provide a false alarm of safety because workers are less able to recognize a scaled-down capability to effectively attend a given task. Additionally, the biochemical marker sampling of fatigue like serum cortisol or blood lactate are invasive thus are not feasible to be applied for rapid, on-site FFW assessment [54]. Without the proper assessment employing valid tools, it can be tough for the worker or supervisor to predict their physiological and psychological fitness level. Studies had shown that migrant workers who made up the main construction workforce who represents a vulnerable group in terms of workplace safety [55]. The use traditional questionnaire survey alone might not be able to quantify the true fatigue level and safety related behavior due to the effect of dynamic construction environment; and workers are likely to underestimate their risk of becoming weaned off [56]. Given the deficiency and shortcoming of the subjective self-assessment survey which is less reliable [57, 58]; and the invasive biochemical test which is less practical to be applied on-site, it is recommended that the adoption of series of objective evaluation tool, in combination with the subjective scale will be a powerful approach in identifying fitness for duty capacity among the construction workers. A longitudinal day-level of fatigue or fitness indicators should be considered to examine the day-level fluctuation of energy resources which denotes fatigue and recovery [59, 60]. In the following sections, we will discuss the suitability of the objective parameters that are in parallel with the physiological and psychological change during construction works. On top of that, the compatible subjective tools to assess fatigue which have been validated specifically among the construction workers will be recommended as the complementary to the objective physical and cognitive performance metrics.
4.1. The physiological and psychological parameters changes related to construction work
It is disclosed that the variations in physiological and psychological parameters related to construction work pose a high risk to the workers [61]. Studies in the past attempted to employ various physiological metrics including heart rate, blood pressure, muscle activity and skin temperature to monitor real-time fatigue during the physically demanding construction tasks [37, 39, 41, 45, 62]. These parameters have the potential in providing early warning signal to detect physical strain through the continuous monitoring at work [63], especially the heart rate which has been generally considered as a reliable index of physiological strain [64]. However, the use of multiple metrics is recommended due to a higher accuracy than using a single parameter while monitoring work fatigue in construction industry [40]. In order to ease the ongoing measurement, the wearable sensing technologies developed however are subjected to technical challenges like limited validity, artifacts, lack of cutoff value for fatigue, acceptance among users and also the privacy issues, which may reduce the accuracy of such parameters in assessing real-time fatigue. To overcome these limitations, the data processing approach is important in order to minimize errors and refine the estimation of task-specific physical fatigue [63]. Other parameters related to the physical and cognitive performance measures such as static balance, muscle strength and response time have also been highlighted [37, 43]. Construction task involves manual lifting which requires several muscle groups to perform actively to attain the kinetic chain of entire body [43]. On the other hand, Postural stability was cited as the most common causes of accidents related to construction work at height. Therefore, the ability to maintain static balance is a critical factor for fall accident prevention [48].
4.2. Subjective evaluation tool for physical fitness
In the workplace, fatigue is a problem that is difficult to quantify, especially when looking into accidents. Moreover, no single tool serves as the gold standard for measuring fatigue due to the extensive effects of fatigue on human capacity, the challenges associated with its characterization, and its underlying causes [65]. Yet, recognizing and accurately assessing the weariness is a crucial first step towards managing it at the job.
The physical strain brought on by physical exertion during work can be measured subjectively. Borg (1970) [66] created the ratings of perceived exertion (RPE), which has been described as one of the most widely used subjective scales to evaluate whole-body and segmental strain. The perceived rating of Borg 6–20 was constructed in line with the linear relationship of the heart rate expected specific exertion level. Despite being cited as the quick and accurate way of measuring heart rates, exertion rates and work intensity in order to predict the risks for work-related musculoskeletal injuries, a single measure of RPE might not be sufficient to capture the overall range of perceptual sensations that worker experience while being physically active [67]. On the other hand, The Baecke questionnaire is a valid and reliable tool to measure the qualitative and quantitative indices addressing several dimensions of occupational physical activity, sport activities and leisure activities [68]. Although easy to apply and had been extensively used in the past few decades, this tool however subjected to recall or reporting bias due to the long recall period. Other than that, the scale is also limited to the examination of the physical aspect without addressing the cognitive dimension.
4.3. Subjective evaluation tool for multidimensional fitness
Workers’ self-reported fatigue symptoms and work ability in relation to work requirements, health status and the worker resources, have been reported as the most commonly used method [69, 70]. Self-reporting surveys are most frequently in field or clinical areas of occupational health [44] because they are easy to administer, less time consuming, and cost effective compared to the biomarkers and electronic device.Fatigue affects fitness for work and work performance [71, 72]. Up to date, while huge body of literature explored on the causes and consequences of occupational fatigue, limited studies have examined the fatigue assessment in the construction sector. Among the validated multidimensional fatigue evaluation scale in the construction industry were Swedish Occupational Fatigue Inventory (SOFI) [44, 46], The Fatigue Assessment Scale for Construction Workers (FASCW) [7, 8, 20], Subjective fatigue symptoms RCIF scale [35, 37]and Work Ability Index (WBI) [47, 49].
The multidimensional Swedish Occupational Fatigue Inventory (SOFI) was developed by Åhsberg et al. [73] and primarily focuses on the unique features of momentary symptom therefore are useful to examine short-termed or acute fatigue symptoms while compared to other scales which focus on chronic features of fatigue or adverse impacts resulted from the delayed recovery [74, 75]. Fatigue instruments like the multidimensional fatigue scale (MFS) and the subjective symptoms of a fatigue test (SSF) were devised to assess general populations or patients with chronic diseases, these scales however are inappropriate in evaluating instant fatigue in workers’ daily working lives [76]. The use of SOFI allows instant detection of fatigue and therefore is helpful in managing relevant safety and health issue or occupational risk in a timely manner [44]. The SOFI tool has demonstrated a satisfactory internal consistency of the subscales [5], has been translated into several languages across nations and was being tested among diverse occupational groups [77–79]. It has been recognized as the primary survey tool to measure whole-body fatigue associated with the physiological, cognitive, motor and emotional responses in which workers are able to express their feelings at the moment of study [5].
The multidimensional Fatigue Assessment Scale for Construction Workers (FASCW) was developed by Zhang et al. [32]. It consisted of only 10-items which is ease to administer taking into consideration of the literacy level of the blue-collar workers. Additionally, the tool has been studied specifically among the construction workers by [7, 20, 32, 80] and was documented its validity and reliability in the evaluation of both physical and mental fatigue in construction industry. The 10-items questionnaire consisted of 3 dimensions (physical inactiveness, mental fatigue and discomfort), with 5 possible Likert- answers where a critical score of 20 and above indicates fatigue [7]. The FASCW tool showed significant high correlations (0.66–0.71) when compared with the Fatigue subscale of the Profile of Mood States (POMS-F), indicating that the FASCW was measuring a similar construct measured by the POMS-F and had good concurrent validity. This tool also had excellent internal consistency and test-retest reliability [32].
The Finnish Institute of Occupational Health (FIOH) developed the idea of the work ability index (WAI) so that employees may assess their own ability to work based on job needs, health conditions, and mental-thinking capacities [81]. This tool decently reflects the interactions between individual physiological, mental and intellectual abilities to work, taking into considerations the working conditions, work performance capabilities, employees’ health status as well as an assessment of social characteristics [82]. Khavanin et al. had employed the WAI tool to evaluate the physical and mental fitness among the tower climbers in the construction industry, reported it as a valid and reliable scale among the manual labors working at height [49]. Another valid that had been applied in the work fatigue assessment among the high-rise construction workers such as scaffolders, steel fixers, form workers, electrician-plumbers and concreters, was the “Subjective Fatigue Symptoms RCIF Scale” defined by the Research Committee on Industrial Fatigue of Japan Society for Occupational Health, 1969. This 30-items questionnaire are classified into three domains of fatigue, namely (i) drowsiness and dullness (general fatigue); (ii) difficulty in concentration (mentally fatigue); (iii) projection of physical impairment (physical fatigue), with dichotomous answer to each fatigue symptoms [83]. Chang et al. (2009) reported those subjective fatigue symptoms highlighted in the tool were coincided with the life tyle of some workers while the extent of fatigue strains demarcated among construction workers of different task. For example, the scaffolders, steel fixers and form workers who working at height were being categorized as physically demanding fatigue task, indicated by more complaints of “projection of physical impairment” than ‘‘drowsiness and dullness” and ‘‘difficulty in concentration” post shift in comparison with pre-shift measurement [37].
Occupational fatigue research in the past decades had almost exclusively implemented subjective questionnaires assessment alone based on the self-perceived fatigue and work ability. Such subjectivity might not representative of actual human performance-based functionality thus can easily be manipulated in order to reflect the desired outcome [84]. Although subjective questionnaires are inexpensive, administering them on building sites is inconvenient and impossible. The recall bias is often reported as the biggest limitation with this strategy. The self-reported survey utilizing questionnaires, nevertheless, are unable to detect real-time physical weariness while causing little disruption to existing on-site activities [45].
4.4. Objective measurement of physiological metrics
Self-reported fitness might differ from the true fitness level. The development of advanced wearable sensors for real-time monitoring of physiological indices such as heart rate, skin temperature, breathing rate and electrodermal activity have provided new opportunities for the objective and continuous monitoring of physical fatigue during construction works. The sympathetic nervous system will be activated during vigorous physical activity, therefore generating specific physiological responses like the increase of heart rate, breathing rate and skin temperature. As a result, continuous monitoring these responses might be possible to identify physical fatigue besides giving clues on FFW [40, 63]. Multiple studies have employed heart rate, or heart rate in combination with breathing rate and local skin temperature monitoring to estimate physical strain among construction workers during experimental study with simulated work [35, 36, 38, 39, 42, 45, 85]. Furthermore, Aryal et al. [45] combined local skin temperature and HR measures in the development of fatigue assessment model, showed the 72% of prediction accuracy for identifying construction physical workload using both skin temperature and HR data. The wearable technologies to monitor cardiorespiratory and thermoregulatory parameters had been documented as the valid objective tool to detect physical fatigue. However the adoption of multiple, rather than single parameter is highly recommended [86]. The successful of physiological indices monitoring greatly depending on workers’ cooperation to bear with the wearable sensor while performing task, the acceptance by construction workers as well as the cost that need to be considered by the employer.
4.5. Objective measurement of physical performance measure
The objective work fatigue evaluation, which integrates the musculoskeletal assessment, offers detailed data on a potential employee’s physical strength and cardiovascular health to help determine whether they can perform the duties necessary for a job function [26].These performance measures will reflect a balance between work demands and the individual resources of a worker to meet those demand.
4.5.1. Musculoskeletal capacity.
Fatigue has been reported decrease the muscle force, strength and endurance thus reduce the ability of muscle to perform [87].The musculoskeletal capacity has been recognized as relevant individual factor to be taken into consideration as a work ability predictor in occupations with high physical demands. This element’s operational definitions include hand grip strength, balance, upper- and lower-limb endurance, trunk flexibility, and trunk flexion and extension strength [88]. The hand grip strength was defined as the predictor and adequate measurement for generalised muscle strength. Furthermore, this single useful test is low cost and suitable to be used in a time-efficient manner in construction site [35, 37, 43]. Nevertheless, the limitation of strength tests, of grip and pinch strength have been identified in which they are likely to be intentionally biased if subjects competing one another during the measurements [35]. The trunk and back endurance strength with its association with the test time, are among the important physical performance measures among the construction workers as they predict abdominal muscle functionality while the fall arrest system like harness and lanyard are worn [43].The tests were selected due to the relation to lifting and work at height capacity, most importantly easy to administer in the real work setting. Among the trunk endurance tests recommended by Mohapatra et al. including prone plank to examine trunk stability, trunk flexor endurance test, trunk extensor endurance test (as known as the Biering–Sørensen test) and trunk lateral endurance test (as known as side bridge test to evaluate the endurance of lateral core muscle). The trunk extensor test, besides assessing core endurance, has been commonly used to measure the endurance of back and hip musculature strength [43].
4.5.2. Flexibility.
Due to the mobility of the soft tissues surrounding the joint, physical exhaustion may alter the range of motion or flexibility of joints, leading to a condition known as fatigue-induced soft tissue shortening over time [89]. Flexibility is the capacity of a joint or group of joints to move freely and without experiencing any pain. Although everyone’s ranges of flexibility differ significantly, maintaining joint and overall body health requires certain minimal ranges. Although radiography and goniometry appear to be the finest tools for evaluating flexibility, their high technical requirements make them unsuitable for application in all contexts [90]. The sit-and-reach test, created by Wells and Dillon in 1952 and its various iterations, has historically been a part of fitness test batteries for assessing hamstring and lower back flexibility. This test is suitable for use as a flexibility measure across various populations in an occupational setting [91] including construction industry [78].
4.5.3. Postural stability and control.
According to the European Commission, postural stability issues are one of the most frequent reasons for accidents involving people who operate at heights [48]. Employees who work at heights must contend with a task that must be completed exactly as well as challenging external conditions, including weather like heat, humidity, high winds, and rain. Only workers with the appropriate amount of experience, qualifications, and physical and mental attributes should be given such employment [92]. The postural stability assessment was cited as the most essential element of fall accident prevention [48]. According to research linking fall risk, people control their posture by increasing the neuromuscular activity of their lower limb muscles and stiffening their ankle joints. The capacity to maintain upright posture while maintaining postural stability is thought to be a crucial component in reducing loss of balance and falls. Afferent input from the visual, proprioceptive, and vestibular systems is crucial for influencing the control of stability [93]. The one-leg standing test with eyes open (OLST-EO) and closed (OLST-EC) were frequently employed for the reliable traditional evaluation of postural stability [48]. The test is able to evaluate balance in a static position with and without a vision control. For construction workers equipped with on-site wearable inertial measurement units, Umer et al. developed a static balance monitoring tool for the proactive tracking of postural stability using a machine learning algorithm (WIMU) [39]. The created technology offers a unique and useful method to boost fall risk surveillance among construction workers carrying heavy manual material and working on slanted surfaces that might disrupt postural stability [94]. The WIMU, however, only explored a single duration of labour assignment to generate changes in static balance and only permitted the measurement of static balance rather than dynamic balance.
4.6. Objective measurement of cognitive performance measure
Given that FFW is multidimensional incorporating physical and mental capacity, construction tasks involve planning and thinking to exercise the cognitive function; subsequently followed by physical function execution where physical task is executed with physical strength [8]. Cognitive performance measure is therefore another important dimension of FFW to be given attention. Studies had documented the wide use of a variety of on-screen test such as Critical Flicker Fusion frequency (CFF) and simple reaction time (SRT) test to measure fatigue in healthy working population to measure the response to visual stimulus which indicates attention or concentration [95]. Other study demonstrated the prevailing indirect mental fatigue measurement by measuring the reaction time using the Personal Computer- Psychomotor Vigilance Test (PC-PVT). Independent researchers, laboratory studies, and field tests have all acknowledged PC-PVT as the only technology with solid validation evidence, and the majority of researchers believe it to be the best way to objectively evaluate fatigue [80]. The effects of acute fatigue on verbal fluency, communication, decision-making capacity, creative thinking, planning, executive control, and novelty performance have been the subject of research. Data overwhelmingly showed that even with mild degrees of weariness, all of these sophisticated cognitive tasks were severely worsened [96]. The 5-minute test was ease to be performed on construction site in the morning prior to the start of work task, and Ferrada et al. [50] reported that the mean reaction test was significantly correlated with the fatigue level indicated by self-reported sleep hours. According to the thorough analysis conducted by Dawson et al. [97], PC-PVT is the most favored objective technique for assessing fatigue at specific periods in time in the field.
4.7. Strength and limitations
To the best of the authors’ knowledge, this critical review is the first which provides an overview of the subjective and objective assessment tool to evaluate the fitness for construction duty in term of physical performance or cognitive performance or both, based on the existing literature. Despite being conducted using the standardized PRISMA guidelines for systematic reviews and extracting relevant studies via systematic search from three different databases, this present study has several limitations. The language bias and publication bias need to be addressed as the limitations The review process did not consider articles published in languages other than English. Moreover, the unpublished research was also not included which might potentially exclude some relevant articles. The heterogenicity or high variability among all included study in term of the working tasks, assessment tool, dimension, study population and study design did not allow the performance of meta-analysis combining the results.
The critical analysis has summarized the tools to evaluate fatigue among construction workers into two main categories, namely objective measurement instrument and the subjective self-administered survey. Construction is a dynamic industry with challenging conditions which are always evolving, which requires considerable physical and cognitive efforts. Traditional methods of recognising exhaustion rely on arbitrary questionnaires that do not enable accurate and immediate detection. These questionnaires rely on responses to predetermined inquiries about the respondent’s physical and mental states to provide a subjective assessment of weariness. Given that 20–40% of construction workers typically work above their bodies’ physiological limits and exhibit signs of weariness [58], the sensor- based physiological monitoring and computerized cognitive performance measure will be more reliable and accurate in determining the physiological state of a person, in order to detect weariness. On the other hand, the compatible subjective tools to assess fatigue which have been validated specifically among the construction workers could be recommended as the complementary to the objective physical and cognitive performance metrics.
5. Conclusions
This critical review provides preliminary insight on various tools and parameters used to evaluate work fatigue in the construction field, besides offering guides on the tool selection which should address the specific functional capacity required for task. Given that the construction has been recognized as a highly hazardous industry which involves huge workforce, future research should focus on the exploration of on-site practicality, the evaluation of cost benefits, and to strengthen the tool validity among construction workers of different task such as manual material handling, working and height or general worker. The findings from present review are critical for occupational health-related and human resource-related policy makers in formulating evidence-based strategies in the management of work-related fatigue and its consequences in the construction industry.
Supporting information
S1 Checklist. Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist.
https://doi.org/10.1371/journal.pone.0287892.s001
(PDF)
S1 Appendix. The details of mixed method appraisal tool (MMAT) assessment.
https://doi.org/10.1371/journal.pone.0287892.s002
(DOCX)
Acknowledgments
We would like to thank the Dean of Faculty of Medicine, Universiti Kebangsaan Malaysia and the Department of Public Health Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia, for the technical support and permission to conduct this study.
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