An Overview of Strategies for Reducing Upper Extremity Physical Exposure Associated With Floor Mopping: A Systematic Review

Abstract

Objective:

This systematic review synthesizes literature on upper extremity physical exposure associated with floor mopping, in order to (a) assess the impact of changes in mopping systems on physical exposure and (b) propose recommendations for strategies to reduce exposure.

Background:

Floor-cleaning tools and equipment have undergone major improvements. Existing studies have focused on mop design modifications and cleaning efficiency. However, less is known about strain responses caused by modern tools and methods.

Method:

Studies from 1987 to February 2017 were identified by electronic and manual search. All selected studies underwent a quality assessment. The evidence was organized into categories representing different strategies for reducing exposure. The levels of evidence were determined using a best evidence synthesis approach.

Results:

Eleven studies were included. Based on the review findings, currently there is moderate evidence suggesting that reduced physical exposure has been achieved through development of mopping systems. Levels of evidence for strategies associated with positive effects on physical exposure were: moderate evidence for mop design and handle type, insufficient evidence for mopping technique, and mixed evidence for mopping methods and environment modifications. Therefore, the present study suggests the use of adjustable mop handles as a strategy for reducing physical exposure.

Conclusion:

A more comprehensive approach to reducing physical exposure concerning floor mopping work is necessary.

Application:

Knowledge regarding physical exposure reduction can be applied as the basis for decision making in cleaning practice. Information can be incorporated into future research regarding development of floor-cleaning methods.

Keywords

physical ergonomics physical work (loading)tools upper extremity musculoskeletal system

The prevalence of work-related musculoskeletal disorders (MSDs) is high in the cleaning industry (Chang, Wu, Liu, & Hsu, 2012; Woods & Buckle, 2000). The wrist and the neck-shoulder region are frequently reported areas of pain and discomfort among cleaners (Chang et al., 2012; Woods & Buckle, 2006). These MSDs in the upper extremities can be caused by exposure to physical risk factors, such as posture, repetition, and force (Bernard, 1997; Gallagher & Heberger, 2013). Therefore, efforts to prevent MSD should include mitigation of these occupational risk factors.

Despite developments in cleaning technology, many cleaning tasks are still performed manually. Upper extremity musculoskeletal disorders (UEMSDs) among cleaners exposes a great need for research into the risk factors associated with the most commonly used cleaning methods. Floor mopping is a strenuous cleaning task performed in diverse spaces such as government offices, commercial office buildings, and commercial recreational spaces (Weigall, Simpson, Bell, & Kemp, 2005). A survey of 1,216 cleaners in the United Kingdom reported that 89% of cleaners mop or wipe floors frequently during the day (Woods & Buckle, 2006). Among Swedish cleaners, as much as 70% of working time spent in cleaning offices is devoted to mopping (Hägg et al., 2008). Manual mopping (i.e., use of nonelectric floor mops) is commonly performed by pushing the mop or by using a wiping motion in either a figure-of-eight pattern (i.e., moving the mop in an arc) or in a back-and-forth pattern.

Mopping involves repetitive movements, awkward postures of the wrists and arms, as well as high force requirement for the hands (Woods & Buckle, 2006). The traditional scrub and cloth method (in which cleaners manually wet and rinse the cloth) has gradually changed to the use of a range of mopping methods. Mopping systems differ with regard to mop head design (e.g., round head mop, flat mop), handle design, and bucket type. Nowadays, conventional wet mopping practices have been replaced by the use of microfiber mops that eliminate the wringing of mops and reduce the amount of water in the mop. Major technical advancements have been made in the design of hand tools, such as adjustability, all-round joints, and reachable handles (Pekkarinen, 2009). Based on extensive equipment assessments, design modifications to mopping systems have been recommended (Woods & Buckle, 2005). Although there has been a great deal of interest in the gradual evolution of mop design and the increasing effectiveness of new methods in recent decades, much less is known about the new technology’s role in offering a solution for reducing the risk of injury and disorders.

In the early 2000s, a literature review by Blangsted, Vinzents, and Søgaard (2000) found floor cleaning to be a strenuous work task for shoulder muscles regardless of the method or tool used. It is uncertain whether the physical load associated with mopping has changed over the past decades due to improvements in mopping systems. Preventive strategies for reducing physical exposure while mopping may contribute to a decrease in MSD. Further, ergonomics measures may increase resources for coping with mopping work regardless of musculoskeletal impairment. However, there appears to be a gap between theory and practice, as it seems that strategies for preventing work-related MSDs associated with mopping are often based on tradition and personal experience rather than on scientific evidence.

To our knowledge, no systematic review exists exploring the relationship between floor mopping and upper extremity exposure. Information is scattered throughout the scientific literature. There is a need for a synthesis of research results on exposure to physical risk factors associated with floor mopping in order to ascertain which improvement strategies could be used as good examples for reducing upper extremity workload in cleaners. Such a review could provide important information identifying gaps in knowledge and guiding further cleaning research for developing floor-cleaning methods.

The aim of the present study was to explore the research evidence to determine which preventive strategies are successful in reducing upper extremity exposure associated with floor mopping. This systematic review identified studies that examined upper extremity exposure to physical risk factors associated with floor mopping under different mopping conditions and synthesized the literature in order to assess whether or not the technical improvements in mops and manual floor cleaning methods have reduced cleaning professionals’ (e.g., cleaners, janitors, custodians) exposure to physical risk factors. The research questions were: (a) Do changes in mopping systems (e.g., tools and methods) manage to reduce physical exposure associated with floor mopping work? (b) What are the recommended preventive strategies for reducing or eliminating physical exposure associated with floor mopping? Figure 1 illustrates the conceptual framework that is used as the foundation for this study.

Method

Search Strategy

An electronic database search was conducted in the PubMed, Scopus, CINAHL (EBSCO), Web of Science, and ProQuest (Health & Safety Science Abstracts) databases from the years 1987 to February 2017. The search was performed to identify all possible studies related to exposure to physical risk factors for upper extremity MSDs while floor mopping. A systematic electronic search was performed by two reviewers (MAW, SJP). After eliminating duplicate articles, the two reviewers independently screened each title and abstract against the inclusion criteria. The full texts of studies were obtained for those that appeared to meet the criteria, or where there was insufficient information to be certain. On obtaining the full text, the inclusion and exclusion criteria were reapplied (by the two independent reviewers), and those that did not meet the initial criteria were excluded from the final review. Possible discrepancies were resolved with the assistance of a third researcher (KR). The interrater agreement for final article inclusion was calculated using a measure of percent agreement. Reference lists of the included papers and relevant reviews were also searched manually. Grey literature from the Google Scholar database was searched by searching the included article titles.

A systematic review was performed in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (Moher, Liberati, Tetzlaff, & Altman, 2009). The results of the search strategy were summarized in a flowchart including study identification, screening, eligibility, inclusion, and analysis (Figure 2).

The comprehensive search terms were generated with the assistance of an information specialist. Search strings were modified for each individual database (see Appendix A). Terms for “floor mopping” were used in AND-combinations with terms for “upper extremity” and search terms representing “physical exposure” (Table 1). All relevant search terms were searched for in their singular, plural, and genitive forms. The search was limited to Humans and the English language. A time limit (years 1987–2017) was used. Medline records were excluded in the CINAHL and Scopus searches.

Table 1:

Literature Search in PubMed

Search	Query
#1	Mopping AND Upper extremity
#2	Mopping AND Exposure
#3	#1 OR #2
#4	Mopping AND Upper extremity (MeSH)^a
#5	Mopping AND Exposure (MeSH)^a
#6	#4 OR #5
#7	#3 OR #6

Note. All Fields search. Filters: Human, English, and time limit 1987-2017.

Medical Subject Heading (MeSH).

Inclusion and Exclusion Criteria

Inclusion and exclusion criteria were decided a priori by the researchers. The inclusion criteria were original studies investigating floor mopping and upper extremity physical exposure in cleaners (or people in related professions), multiple study types, articles published in English in peer-reviewed journals, conference proceedings (i.e., a full paper), or technical reports (years 1987–2017). The inclusion criteria also included the requirement that upper extremity exposure was quantified in the workplace or laboratory settings by exposure assessment techniques such as direct measurements, observation-based assessments, or self-reported methods. The papers had to be available electronically. The exclusion criteria employed in the search were: reviews, book chapters, doctoral theses, and conference abstracts (i.e., a brief summary of a conference paper). Studies that examine only the usability of equipment (i.e., with no accompanying assessment of exposure) or mopping in a household environment were excluded. Double issue and data presented as general observations were also excluded. Multiple publications based on the same study population were retained if the analyses were conducted for different exposures or outcomes.

Assessment of Methodological Quality

The purpose of the critical appraisal in this review was to assess the methodological quality of each study and the extent to which each study addressed the possibility of bias in its design, conduct, and analysis. Two independent reviewers assessed the methodological quality of the included studies using the Joanna Briggs Institute (JBI, 2016) critical appraisal checklists for Analytical Cross-Sectional Studies or Quasi-Experimental Studies depending on the type of study. JBI tools do not specify a cutoff value in order to differentiate the study quality levels, so we scored the methodological quality as “low” (<4), “medium” (≥4), and “high” (>6) in both the observational and the experimental studies. Appraisal criteria were also applied to the conference proceedings even if their brevity limited the provision of methodological detail. All studies were included in the summary regardless of their methodological quality. In addition, the overall quality of the studies was evaluated under the headings of bias and strength of the results. The interrater agreement for critical appraisal was calculated using measure of percent agreement. Any disagreements were resolved by consensus.

Data Extraction and Synthesis

One reviewer (MAW) extracted and tabulated the following data from each study: author(s), study design, type of mop used, sample characteristics, exposure assessment methods, outcome measures used, and relevant research results. A second reviewer (SJP) audited the accuracy of the data extraction.

The evidence synthesis was based on a best evidence synthesis approach (Slavin, 1995). The evidence was organized into categories representing different strategies for reducing exposure. The effect of a particular strategy on physical exposure (i.e., posture, force, repetition, electromyographic (EMG) activity, perceived exertion) was evaluated and the findings were tabulated. Owing to the heterogeneity across outcome measures, study designs, and reported data, results were synthesized by using a specific criterion for combining the findings. This criterion included the requirement that the ergonomic measure have a positive effect on upper extremity physical exposure, such as reduction in exposure level, duration, or frequency. The positive effect was classified as (+) when the factor resulted in reduction in physical exposure, (—) when no effect was observed, and (n/a) when the effect was not measured. A study with both positive effects and no effects was classified as a positive effect study. The direction of the effect was considered along with the study quality rating and the number of studies to determine the levels of evidence (see Table 2). Five levels of evidence were defined based on the synthesis guidelines adapted from the study by Brewer et al. (2006). The synthesis approach first answered the general question about the effect of changes in mopping systems on physical exposure, and this was followed by an evaluation of the specific categories of strategies. Each category of evidence was paired with practical messages, a practice adopted from the study by Eerd et al. (2016). In other words, a strong level of evidence leads to recommendations whereas a moderate level of evidence leads to recommendations for “practice considerations” (see Table 2).

Table 2:

Evidence Synthesis Guidelines

Level of evidence	Minimum quality^a	Minimum quantity	Consistency	Practical message
Strong	High	≥ 3 studies	All high-quality studies converge on the same findings	Recommendations
Moderate	Medium	≥ 2 studies	Majority of medium-quality studies converge on the same findings	Practice considerations
Mixed	Medium	≥ 2 studies	Medium- and better-quality studies have inconsistent findings	Not enough evidence to make recommendations or practice considerations
Partial	Low	≥ 2 studies	Majority of low-quality studies converge on the same findings
Insufficient	The above criteria are not met

In quality assessment: high = scores > 6; medium = score ≥ 4; low = score < 4 (maximum scores: 8–9).

Results

Identification of Studies

A total of 2,170 records were identiﬁed from the search of the five databases (Figure 2). After removing 168 duplicates, the remaining 2,002 studies were further screened based on the inclusion criteria. Following title and abstract screening, 24 full-text papers were reviewed. Of these, nine studies were assessed as meeting the inclusion criteria. Five articles were retrieved through manual search. Based on the eligibility criteria, 14 studies were included. However, three studies that fulfilled the eligibility criteria (Chang et al., 2012; Tantuco, Mirasol, Oleta, & Custodio, 2016; Weigall et al., 2005) were eliminated from the evidence synthesis because there was inability to isolate a unique contribution of any specific strategy to the physical exposure effect. In the end, 11 studies were included for evidence synthesis. There was good agreement (96%) between the two independent reviewers on the final inclusion of studies.

Study Characteristics

Of the included studies, eight were research articles and three were conference papers (Table 3). Three were observational studies and eight were experiments. All the experiments were within-subject designs.

Table 3:

Study Characteristics and Upper Extremity Related Outcomes and Results of the 11 Research Papers Included in the Review

Study, year (origin)	Study design and type	Sample, gender, and age (years)	Mop type	Exposure assessment methods*	Outcome measures	Relevant results
Cabeças, 2007 (Portugal)	Observational, CS	n = 20, 95% females, age 42, n = 6 (floor mopping); n = 8 (cotton wet mopping)	Cotton dust mop with washable cloth and quick-change frame; cotton wet mopping with a cotton yarn, using a string mop	EMG, modified application of the Strain Index (SI) method, observation in the workplace, video recording	Mean values of %MVC for the flexor carpi ulnaris and extensor carpi ulnaris muscles; mean SI score (for different cleaning methods); effort-related variables in four trigger levels; mean effort intensity (%MVC), effort duration (% of time in effort) and effort frequency (peaks per minute)	No significant differences in muscle activity between mopping using a dust mop and a cotton wet mop. Mopping was among the cleaning activities with a comparatively lower risk to distal upper limb disorders.
Conner & Irwin, 2009^c (USA)	Experimental, within-subject	n = 6, 1 female, 5 males, age 30	A flat mop with a microfiber pad, mop and bucket, backpack system, and bent-handled applicator	EMG	Percentage of the integrated EMG value of flexor carpi radialis, middle deltoid, trapezius muscles while using four different applicator systems; normalized by peak value of rectified and smoothed EMG (%MVC)	Physical effort (EMG) was lower while using bent-handled applicator compared with flat mop as well as mop and bucket system. There was no significant difference between backpack system and bent-handled applicator.
Hagner & Hagberg, 1989 (Sweden)	Experimental, within-subject	n = 11, females, age 35	A mop handle with a rinsed and wrung cloth	Video analysis, EMG	Abduction of the upper arm at three abduction ranges: < 30°, 30 to 60° and > 60° for “push” and “figure-of-eight” mopping techniques; the static and median load levels (APDF) of upper trapezius muscle activity (%MVC) bilaterally for “push” and “figure-of-eight” mopping techniques	Less local muscle load and perceived exertion while “push” mopping technique than “figure-of-eight” technique. Both mopping techniques exceeded the acceptable static load levels of 2–5% of the MVC.
Hopsu, Toivonen, Louhevaara, & Sjøgaard, 2000^c (Finland)	Experimental, within-subject	n = 48, females, n = 41 (OWAS), n = 30–37 (EMG), n = 41 (RPE), age 43	Seven different mopping methods (the amount of water ranging from dry to wet)	EMG, Ovako Working Posture Analysis System (OWAS) method, video analysis, RPE (e.g., the ratings of perceived exertion for the arms)	Average EMG values (%MVC) of upper trapezius muscle and forearm muscles for the standardized mopping task for seven different mopping methods; upper arm postures (below/above shoulder height); ratings of perceived exertion for the arms (RPE 6–20)	The local muscular strain was higher with the use of wet and damp mopping methods compared with dry methods. Dry mopping methods were recommended.
Kumar, Chaikumarn, & Lundberg, 2005a (Sweden)	Experimental, within-subject	n = 10 (mopping), females, ages 24–54	Not reported	Participatory workshop method, video recordings for postural analysis with OWAS method	Working postures: % of mopping task arms below or above shoulder level (proportion of mopping task in action category 1–4)	In office mopping task, arm postures were improved when electric cords were attached above the floor.
Kumar, Hägg, & Öhrling, 2008^c (Sweden)	Experimental, within-subject	n = 10, gender not reported, age 42	Common floor mopping tool	EMG	Average muscle activities for extensor carpi radialis, anterior deltoid, and upper trapezius bilaterally (%MVC)	No significant differences were detected in muscular activity while mopping on a polished floor compared with a nonpolished floor.
Öhrling, Kumar, & Abrahamsson, 2012 (Sweden)	Experimental, within-subject	n = 13, gender not reported, age 48	Adjustable mop handle (with pressed push-button), nonadjustable mop handle, microfiber dry mop	EMG, perceived exertion ratings on a CR-10 scale for areas in the upper body	Mean muscle activities (%MVC) for upper trapezius, middle deltoid, and wrist extensor bilaterally; perceived muscular load of upper body	Physical load during staircase mopping was decreased by using adjustable mop compared with nonadjustable mop. Adjustable mops were rated as less strenuous than nonadjustable mops.
Søgaard, Fallentin, & Nielsen, 1996 (Denmark)	Observational, CS	n = 6 mopping, n = 6 scrubbing, females, age 52	Minimop, scrub and cloth	EMG, video-based kinematic analysis	The static, median, and peak load levels (APDF) of trapezius muscle activity (%MVC); muscle fatigue: changes in EMG amplitude and frequency content; work cycle time; upper arm abduction angle (°), amplitude of arm abduction (°), and abduction velocity (°/s)	Mopping cannot be recommended as less strenuous than traditional scrub and cloth method. More arm abduction for the LP-arm while mopping compared with scrubbing. No significant differences between the two methods were found with regard to either muscle load or work cycle times.
Søgaard, Laursen, Jensen, & Sjøgaard, 2001 (Denmark)	Experimental, within-subject	n = 6, females, age 46	Minimop (a round-headed mop with long threads) and scrubbing brush with cloth, both with ordinary handle and force handle (the latter equipped with force dynamometers)	EMG, force dynamometers, video-based kinematic and kinetic analysis (motion analysis with reflecting markers, a link segment model of the upper extremities and force measurements)	The static, median, and peak load levels (APDF) for trapezius, infraspinatus, and medial deltoid muscles bilaterally (%MVC); flexion/extension and abduction/adduction angles for shoulders; flexion/extension angles for elbows; flexion/extension, abduction/ adduction, and outward/inward rotation moments of force (Nm) in shoulders, flexion/extension moment of force in elbows (mean, peak and % of cycle time), relative moment of force	No significant differences in the static level for the six shoulder muscles were found between floor mopping and scrubbing. Changes in moments of force in the shoulders were minor. Changing the floor cleaning tool is not a sufficient preventive strategy for reducing the load on the shoulder muscles.
Wallius et al., 2016 (Finland)	Experimental, within-subject	n = 13, 12 females, one male, age 41	An aluminum telescopic mop handle; a 60 cm wide mop frame; microfiber mop with 60 ml of water	EMG, perceived exertion ratings on a Borg’s category ratio scale (CR-10 scale) for shoulder area	The 10th, 50th, and 90th percentiles of APDF of EMG from upper trapezius, infraspinatus, middle and anterior of the deltoid muscles (%MVC) for UP-hand; four different mop handle heights compared; perceived exertion ratings for shoulder area (scale 0–10)	Increased mop handle height was associated with higher muscle activity levels and higher subjective perceptions of exertion. Mop height adjustment between chin and shoulder level may be recommended as a basis for floor mopping with a “figure-of-eight” technique.
Woods & Buckle, 2005 (United Kingdom)	Observational, CS	n = 60 (workplace assessments), n = 25 (observation), n = 10 (user trial), females, age 49	Round-head mop, long-tailed mop, and flat mop; two handheld mop squeezing mechanisms: standard bucket and hand lever bucket	Workplace assessments (observation method), user trial in laboratory (expert assessment of the upper limbs), force gauge, electrogoniometer	Wrist flexion/extension, radial/ulnar deviation angles (% of time wrist postures outside 50% of maximum angles); arm postures; hand force (N)	There were high levels of hand force no matter the types of hand squeezing mechanisms used. Problems with the ergonomics of mopping systems were identified and practical suggestions for equipment selection and design modifications were suggested.

Note. APDF = amplitude probability distribution function of EMG: static, median, and peak load level, 10th, 50th, and 90th percentiles; CS = cross-sectional; EMG = surface electromyography; LP = lower position; %MVC = percentage of maximal voluntary contraction (normalized values); UP = upper position.

Methods only for upper extremity exposure assessment.

Conference paper.

Most of the studies took place in Europe (n = 10, [91%]). Self-reported, observation-based, camera-based, and direct measurement exposure assessment techniques were adopted (Table 3) both in laboratory and field conditions. The study sample for instrumented measurements ranged from six (Conner & Irwin, 2009; Søgaard, Laursen, Jensen, & Sjøgaard, 2001) to 37 (Hopsu et al., 2000). All studies except one (Conner & Irwin, 2009) involved a majority of female cleaning professionals. However, two studies did not report the gender of participants (Kumar, Hägg, & Öhrling, 2008; Öhrling, Kumar, & Abrahamsson, 2012).

Critical Appraisal

The included studies were critically appraised using the JBI tools. JBI quality scores ranged from 4 to 6 (Quasi-Experimental Study) and 3 to 6 (Observational Study). Ten of 11 studies included in this review were rated as being of “medium” quality, with one study rated as being of “low” quality (Appendix B). There was good agreement (90%) between the two independent reviewers on the critical appraisal of the studies.

Bias

No randomized control studies or longitudinal studies were found. As to establishing a cause-and-effect relationship, in all the experiments analyzed it was clear which variable was measured as an independent variable (“cause,” e.g., mopping method) and as dependent variables (“effect,” e.g., muscular load; item 1, Appendix B). Further, in each study the outcomes were measured in the same way in compared groups (item 7, Appendix B).

There were no control groups in any of the included experiments (item 4, Appendix B). However, all the experiments used within-subject design, in which the participants served as their own control. Therefore, there were no differences between participants included in the compared groups (item 2, Appendix B). In most experiments, the reliability of measurements performed was good. However, there was lack of reporting as to intrarater or interrater reliability within the studies (item 8, Appendix B).

In the included observational studies, the potential confounding factors (e.g., lack of control for the presence of other cleaning tasks) were identified in all studies. However, strategies to deal with them were not always stated (or not applicable) (items 5–6, Appendix B). Further, the study sample as well as the study participants and settings were not clearly defined in some (2/3) observational studies (items 1–2, Appendix B).

Strength of results

The majority of studies (9/11) used appropriate methods of statistical analysis (items 8 and 9, Appendix B), thus increasing the strength of the results obtained. However, most studies included relatively small samples (Table 3), and none of the studies calculated their sample size based on a power calculation (for the instrumented measurements). Further, it was deemed inappropriate to synthesize results by means of quantitative strategies because of the methodological differences (e.g., methods, outcome measures) in the included studies (Table 3). Therefore, a best evidence synthesis approach was utilized.

Description of Results

The activity of mopping under different conditions was divided into the following four categories that represent strategies for reducing exposure: (a) mop design, either specific mop design factor (handle type) or type of tool (comparison of alternative types of tools and the associated equipment); (b) mopping methods (e.g., evaluation of different mop head materials used); (c) mopping technique (i.e., the manner in which the mopping is performed); and (d) environment modifications (e.g., change in environmental conditions associated with mopping; Table 4).

Table 4:

Synthesis of Studies on Examining Upper Extremity Exposure to Physical Risk Factors Associated With Mopping Under Different Conditions (Includes Strategies for Reducing Exposure)

Studies	Strategy#	Posture		Force	Muscle activity		Repetition	Perceived exertion
Studies	Strategy#	Arm	Wrist	Force	Arm	Wrist*	Repetition	Perceived exertion
Cabeças (2007)	Method	n/a	n/a	n/a	n/a	—	n/a	n/a
Conner & Irwin (2009) ^c	Mop design	n/a	n/a	n/a	+	+	n/a	n/a
Hagner & Hagberg (1989)	Technique	+	n/a	n/a	+	n/a	n/a	n/a
Hopsu et al. (2000) ^c	Method	—	n/a	n/a	+	+	n/a	—
Kumar et al. (2005a)	Environment modification	+	n/a	n/a	n/a	n/a	n/a	n/a
Kumar et al. (2008) ^c	Environment modification	n/a	n/a	n/a	—	—	n/a	n/a
Öhrling et al. (2012)	Mop design	n/a	n/a	n/a	+	+	n/a	+
Søgaard et al. (1996)	Mop design	—	n/a	n/a	—	n/a	—	n/a
Søgaard et al. (2001)	Mop design	—	n/a	—	—	n/a	n/a	n/a
Wallius et al. (2016)	Mop design	n/a	n/a	n/a	+	n/a	n/a	+
Woods & Buckle (2005)	Mop design	n/a	n/a	—	n/a	n/a	n/a	n/a

Note. (—) = no effect; (+) = reduction in exposure (level, duration, or frequency); (n/a) = no comparison of methods conducted or effect of ergonomic measure on exposure not examined.

#Strategy: different mopping conditions studied (e.g., mopping method compared).

Wrist or forearm.

Conference paper.

The most common physical exposure outcome was muscle activity (load), which was noted in nine studies (Table 4). Four studies quantified shoulder muscle activities in terms of amplitude probability distribution function (APDF) (Jonsson, 1982). There were five studies that examined posture outcomes and three studies that evaluated perceived exertion (RPE) outcomes. One study examined repetition outcomes (cycle time) and two studies assessed force outcomes (Table 4).

Changes in Mopping Systems

Six moderate-quality studies that examined changes in mopping systems (e.g., methods, tools) indicated a positive effect on physical exposure (reduction in exposure intensity or duration) for the upper extremities (Table 4). Because six moderate-quality studies out of 11 indicated reduction in physical exposure outcomes and five studies (four moderate- and one low-quality) found no effect, application of our evidence synthesis guidelines showed that there exists a moderate level of evidence that changes in mopping systems have reduced upper extremity physical exposure associated with floor mopping.

Those factors that have yielded positive results belong to the following major categories of strategies: (a) mop design (Conner & Irwin, 2009; Öhrling et al., 2012; Wallius et al., 2016), (b) mopping methods (Hopsu et al., 2000), (c) mopping technique (Hagner & Hagberg, 1989), and (d) work environment modifications (Kumar et al., 2005a).

Strategies for Reducing Physical Exposure

Six studies, five of medium quality and one low quality, examined different mop designs: three studies showed reduction in physical exposure outcomes, whereas three studies (two moderate-quality and one low-quality) found no effect on physical exposure outcomes. Therefore, application of our evidence synthesis guidelines showed that there was moderate evidence that changes in mop design reduce physical exposure. The category of mop design was further divided into two subcategories for which evidence synthesis was conducted: (a) handle type and (b) type of tool.

Mop design: Handle type

Two medium-quality studies (Öhrling et al., 2012; Wallius et al., 2016) that examined adjustable-length mop handles found a reduction in physical exposure outcomes. In staircase mopping, using adjustable handles decreased levels of muscle activities for the right-hand shoulder and for the left-hand wrist as well as the subjective perceptions of exertion in comparison to use of a nonadjustable mop (Öhrling et al., 2012). Similarly, Wallius et al. (2016) demonstrated that by adjusting the mop handle, muscle activity levels for the shoulder and subjective exertion ratings for the shoulder area were decreased. These studies provide moderate evidence that the type of mop handle reduces physical exposure.

Mop design: Type of tool

Four studies, three of medium quality (Søgaard et al., 1996, 2001; Conner & Irwin, 2009) and one low-quality (Woods & Buckle, 2005), compared alternative types of tools: one medium-quality study found reduction in physical exposure outcomes and the three other studies showed no effect on physical exposure outcomes (Table 5). One study (Conner & Irwin, 2009) compared four different floor-finishing and cleanup applicators and found a lower level of physical effort for the forearm and upper arm muscles when using a bent-handled applicator compared with the traditional mop and bucket system or a flat mop. In this conference paper, a bent-handled applicator was reported as equivalent to the backpack system. Another study (Woods & Buckle, 2005) compared two types of manual mop-squeezing mechanisms (standard bucket versus hand lever bucket), and showed no differences in levels of hand force between the two squeezing mechanisms. The other two studies (Søgaard et al., 1996, 2001) examined the change from a traditional scrub and cloth method (scrubbing) to mopping with a minimop and detected no significant differences on the shoulder muscle load. In addition, changes in arm posture and moments of force in the shoulders were minor. Therefore, the authors concluded that the change of tool proved to be an insufficient strategy for reducing the shoulder load. These four studies provide moderate evidence for concluding that changing the type of tool has no effect on physical exposure.

Table 5:

Level of Evidence for Preventive Strategies and Accompanying Messages

Level of evidence (direction of effect)	Category of strategies(no. of H, M, and L studies)	Outcome	Message for practice
Strong	*
Moderate (positive)	Mop design: handle type (2M)	Physical exposure (muscle activity, perceived exertion)	Practice consideration
Moderate(no effect)	Mop design: type of tool (3M, 1L)	Physical exposure (muscle activity, posture, force, repetition)	Practice consideration
Partial	*		Not enough evidence from scientific literature to guide current practices
Mixed	Method (2M)	Physical exposure (muscle activity, posture, perceived exertion)
Mixed	Environment modifications (2M)	Physical exposure (muscle activity, posture)
Insufficient	Technique (1M)	Physical exposure (muscle activity, posture)

H = high quality; M = medium quality; L = low quality.

None of the studies met the criteria.

Mopping method

Two medium-quality studies examined mopping methods in which both the material and the moisture level of mop heads were contributing factors. One study (Cabeças, 2007) found no effect on physical exposure while one (Hopsu et al., 2000) showed a reduction in physical exposure outcomes. The conference paper by Hopsu et al. (2000) compared seven mopping methods (ranging from dry to wet) and found that the strain on the shoulder and forearm muscles was significantly lower in microfiber dry or dry mopping methods than in wet and moist methods. Regardless of the method used, no effect on postures or ratings of perceived level of exertion for the arms was found (Hopsu et al., 2000). A study by Cabeças (2007) compared two types of mopping methods: using a cotton dust mop and wet mopping with a string mop. This study reported no significant differences in the wrist muscles’ activities between mopping with these two methods. There was mixed evidence for concluding that use of different mopping methods reduces physical exposure.

Mopping technique

A single medium-quality study (Hagner & Hagberg, 1989) that compared two mopping techniques demonstrated a positive effect on physical exposure outcomes for the “push” mopping technique compared with the “figure-of-eight” mopping technique. This study reported a higher shoulder muscle load and more pronounced arm abduction in the “figure-of-eight” technique compared with the “push” mopping technique (Hagner & Hagberg, 1989). There was insufficient evidence to state that a change in mopping technique reduces physical exposure because there was only one study available.

Work environment modifications

Two medium-quality studies examined the effects of work environment modifications: one (Kumar et al., 2005a) found a positive effect, while one conference paper (Kumar et al., 2008) found no effect on physical exposure outcomes. A study by Kumar et al. (2005a) indicated that modification of office work environment contributed to the cleaner’s working postures while floor mopping; attaching the electric cords above the floor reduced exposure to work with one arm above shoulder level. Another study (Kumar et al., 2008) compared mopping of two different types of floors (polished versus nonpolished) and found no significant differences in the wrist and shoulder muscle activity levels involved in mopping the two types of floors. These studies provide mixed evidence that work environment modifications associated with mopping reduces physical exposure.

Taken together, none of the strategies for reducing exposure met the criteria for a strong level of evidence. There was a moderate level of evidence showing that the type of mop handle has an effect on reducing physical exposure; therefore, we suggest using adjustable handles as a strategy for reducing exposure. Moderate evidence for no effect on physical exposure was found in comparisons of different types of tools used. The remaining categories had too few high-quality studies or contained conflicting evidence across studies; therefore, there is not enough evidence from the scientific literature to guide current practices.

Discussion

This systematic review synthesized the literature related to upper extremity exposure to physical risk factors associated with floor mopping under different conditions in order to assess the impact of changes in mopping systems on physical exposure, and to recommend strategies for reducing exposure.

Over the past 30 years, upper extremity exposure to physical risk factors has been examined under the following four mopping conditions representing strategies for reducing exposure: (a) mop design, (b) mopping method, (c) mopping technique, and (d) environment modifications. Six moderate-quality studies out of 11 studies included in our evidence synthesis indicated positive results in physical exposure reduction. However, currently there is moderate evidence for the claim that upper extremity exposure associated with mopping has been reduced due to the changes in mopping systems.

We identified four strategies (mop design, method, technique, and environment modifications) that provided evidence of reducing upper extremity physical exposure. However, in examining specific categories of strategies, our analysis revealed that none of the studies met the criteria for a strong level of evidence that a specific strategy reduces physical exposure. We found moderate evidence for changes in mop design, as well as for mop adjustability (Öhrling et al., 2012; Wallius et al., 2016), as a successful strategy for reducing physical exposure. However, moderate evidence for no effect on physical exposure was found in comparisons of alternative types of tools (Table 5). Similar findings have been reported earlier in studies of shoulder muscle loading with different types of floor cleaning equipment (Blangsted et al., 2000; Søgaard, Blangsted, Herod, & Finsen, 2006).

In optimizing the use and benefits of the mopping tools employed, individual factors (e.g., technical skills) influence the implementation of new working techniques into actual practice (Jensen, Frydendall, & Flyvholm, 2011; Öhrling et al., 2012). We found insufficient evidence for a change of mopping technique affecting reduction of physical exposure. Only one study (Hagner & Hagberg, 1989) examined mopping technique and reported that use of the “push” mopping technique also significantly decreased the physical exposure level compared with the “figure-of-eight” technique.

Although mopping tools and methods have significantly improved, our study revealed that the research regarding the effects of new mopping systems on physical exposure is disproportionately small. Even if there are diverse types of mop materials available on the market today, only two studies (Cabeças 2007; Hopsu et al., 2000) examined different mopping methods. Both showed inconsistent findings. There is also minimal research addressing the relationship between the physical workload of cleaning workers when mopping and the design characteristics of buildings, furnishing, and facilities. The information provided in this review indicates that there is mixed evidence for environmental modifications as a strategy for reducing physical exposure. A single study (Kumar et al., 2005a) showed that a simple work environment modification (simple attachment of electric cords above the floor of the office environment) influenced cleaners’ working postures positively while mopping. This indicates that environmental factors, such as issues and challenges related to interior design, can also make mopping tools difficult to use properly. Therefore, this finding also emphasizes that cleaning workers’ needs should be taken into account in the interior design process.

Recommendations and Implications for Practice

Based on the findings of the studies reviewed, we can say that one preventive strategy should be considered in the facilitation of cleaners’ adoption of healthy working practices. We found moderate evidence that the adjustability of mops is a technical advancement that has demonstrated reduction of physical exposure. Using adjustable handles decreased levels of muscle activities for the shoulder, and subjective perceptions of exertion both in corridor (Wallius et al., 2016) and staircase mopping (Öhrling et al., 2012). A strategy with moderate evidence can be viewed as a recommendation for “practice to consider.” Therefore, we suggest the use of adjustable mop handles as a successful strategy for reducing upper extremity exposure. Information provided in this review can help guide decision making around the purchase of tools for cleaning work. Although it has been recognized that these kinds of practical and low-cost improvement strategies are important in improving ergonomics in workplaces (Kogi, 2012), it is also essential to distinguish between ergonomic measures themselves and the strategies for implementing these measures. Modern tools can make cleaning work less physically demanding, provided that they are used correctly (Pekkarinen, 2009; Öhrling et al., 2012; Wallius et al., 2016). With regard to mop handles, the length adjustment device is essential in determining whether or not adjustability is used (Öhrling et al., 2012). Therefore, different height adjustment mechanisms are necessary.

Although comparison of alternative types of tools revealed moderate evidence for no effect on physical exposure, this fact should not discourage researchers and practitioners from continuing to develop and conduct research on new mopping tools. The reviewed studies of various types of mops used in many different mopping conditions highlights the need for contextualizing different mopping systems to the task and user. This approach emphasizes the need for collaboration among designers, researchers, cleaning workers, and equipment manufacturers. An example of this kind of contextualization is the study by Kumar, Chaikumarn, & Kumar (2005b), in which redesign of the cleaning tool was shown to reduce trunk postural load in the cleaning of passenger train wagon floors.

The evidence for reduction in physical exposure across the remaining categories of strategies (i.e., mopping method, technique, and environment modifications) resulted in mixed or insufficient evidence as a result of either too few high-quality studies available or conflicting evidence across studies. However, we note that this does not mean that these strategies are not successful. Rather, it means that based on scientific evidence, there is insufficient evidence to support recommending these strategies for reducing physical exposure.

With regard to mopping methods, the evidence was mixed. We found only one study in which dry and microfiber dry mopping methods were demonstrated to be less strenuous than methods utilizing water (Hopsu et al., 2000). Despite the finding in this particular conference paper and the fact that microfiber mops are known for their effectiveness, there is a paucity of studies on different mopping methods. Therefore, no suggestion for practice can be given.

Information provided in this study concerning different strategies for reducing exposure may be necessary for those involved with health and safety issues in the cleaning industry, including occupational health professionals responsible for risk prevention and reduction programs. With regard to the strategies for reducing exposure compared in the present study, regardless of the mop design, method, or technique used, none of the studies included reported positive change in wrist postures or in use of force (Table 4). Similarly, none of the findings of studies analyzed suggests a mean of reducing of the repetitive movements of the upper limbs while mopping. Awareness of these harmful exposures can also guide choices made by designers in the modification of existing tools or the development of new cleaning tools. Decreasing the risk for MSDs resulting from floor mopping will require further research because these exposures (e.g., exertions involving deviated wrist or repetitive hand exertions) are well-known workplace risk factors associated with the increased risk of upper extremity disorders (Keyserling, 2000). As well, a high occurrence of carpal tunnel syndrome has been reported in floor cleaners (Mondelli et al., 2006).

Limitations

There are several possible limitations to this systematic review. Reviews are at risk of retrieval bias; in our review, only articles written in English were included, which itself is a potential source of publication bias. Although a systematic search and additional searches were performed, there remains the possibility that not all relevant literature was located. Some literature had to be excluded because those particular studies examined different cleaning tasks. Data on physical exposure in the course of mopping was not presented separately in them. A systematic search of the grey literature was not conducted; this is another factor which could introduce bias into this review. However, the inclusion of conference proceedings might have helped reduce publication bias. Potential selection bias also arises from the years of publication chosen. Extractor bias is a possible limitation, as only one author of the present study served as the primary extractor of studies identified in the literature search.

The results of this study need to be considered in the context of the limitations imposed by the small number of studies of different levels of quality, small sample sizes, and a gender bias toward females. Those studies with small sample sizes may have been underpowered for detecting differences in the outcome measures. This factor could limit the generalizability of results. However, all the experiments used a within-subject design in which each participant served as his/her own control. Thus, fewer participants might have been required in order to attain the same level of statistical power as experiments utilizing a parallel design. In addition to a risk of decreased statistical power and great risk for type II error, random error is also large when sample sizes are small.

A further limitation of this systematic review lies in the fact that, despite the brevity of the conference papers reviewed, we decided to assess the quality of such papers. It should be noted that we could only judge the information given in the research papers, not the actual conduct of the study. This situation could have affected the quality scores. Further, one of the major limitations of this systematic review was that we were not able to draw direct comparisons between studies because of the heterogeneity of the exposures measured, the outcome measures used, and differences in data presentation. Interpretation of the results of this review should also be treated with caution because many of the exposure reduction strategies discussed above have been the subject of only two studies, and their effects were evaluated based on only some of the biomechanical risk factors. In addition, a limited number of studies was available for the period of the past 10 years.

Given that floor mopping situations are diverse by nature, there was minimal research reporting that main ergonomic principles, user elements, and environmental factors have been taken into account in the tool design process in order to contextualize different mopping systems to the task and user. In general, it is well recognized that new tools and methods need to be contextualized for different cleaning tasks and environments (Kumar & Kumar, 2008; Weigall, Bell, & Simpson, 2006). Further, studies reviewed here did not investigate the long-term effects of mopping, and we did not examine the dose-response relations between physical workload and incidence of MSDs. A more holistic perspective is necessary for improving cleaning work. In addition to physical factors, MSDs in the upper extremities acquired in the course of cleaning work develop from a wide range of psychosocial, work organizational, and individual factors (Weigall et al., 2005). Concentration on physical ergonomics alone is an inadequate approach to preventing the risk of cleaners developing MSDs (Weigall et al., 2005).

Future Directions

Based on the limitations described above, there are several directions for future research that should be pursued. Existing floor mopping tools, methods, and working environments need to be better designed in order to reduce physical exposure and thereby risk for occupational disorders among cleaners. We recommend conducting research that addresses the association between strain on cleaners and the interior design of buildings and furniture. Decreasing the physical load associated with mopping may require introducing ergonomics into the process of mop design. As our identified strategies indicate, a more comprehensive procedure for reducing physical exposure in mopping work is required. In addition to mop design considerations, there are other factors (i.e., working method and technique as well as work environment factors) that should be considered when searching for strategies for reducing exposure in mopping. Researchers, cleaning professionals, designers, and equipment manufacturers should still work in close collaboration in the evaluation of the appropriateness of equipment for particular environments and tasks.

Overall, more studies capable of comparison are needed in order to quantify the association between ergonomic factors and physical exposure reduction in the course of the work of floor cleaning. Future studies should measure exposures to risk factors through direct measurements in order to provide more accurate data and to develop better understanding of the effects of ergonomic improvements on physical exposure reduction. Further, it will be crucial in future studies to utilize well-defined, accurate, and reliable exposure metrics in order to be able to draw conclusions regarding the relation between physical exposure and outcome measures. Future studies may need to be enlarged to include both exposure and health effect variables in order to provide data on exposure-effect relationships. Longitudinal and controlled field studies are important for establishing a causal relationship between intervention and effect.

Conclusion

According to the literature reviewed in the present study, currently there is moderate evidence to suggest that reduced physical exposures have been achieved through development of mopping tools and methods. We found four strategies that showed reduction in physical exposure. However, due to a paucity of high-quality studies, the majority of the strategies (i.e., mopping technique, method, and environmental modification) did not meet the criteria for strong or moderate levels of evidence. Therefore, it is difficult to make strong evidence-based recommendations. Mop design considerations, such as adjustable mop handles, showed moderate evidence for exposure reduction and can be suggested as a practice to consider. Although floor cleaning tools and methods have been improved, we have found only minor evidence of successful strategies for reducing exposure and it appears that mopping still exposes cleaners to a high risk of developing work-related UEMSDs. A more comprehensive procedure for reducing physical exposure is needed. Our findings indicate that researchers, manufacturers, and designers should still strive to reduce the physical stress on cleaners.

Key Points

● This review indicates that, despite developments in mopping systems, physical risks in manual floor cleaning work have not been eliminated.

● Four strategies (mop design, mopping technique, mopping method, and environment modifications) showed insufficient, mixed, or moderate levels of evidence of reducing physical exposure.

● Mop design, such as handle type, showed moderate evidence of physical exposure reduction. A practice to consider is the use of adjustable mop handles to reduce upper extremity physical exposure.

● More comprehensive strategies are needed for reducing physical exposure in floor mopping work.

Footnotes

Appendix A

Appendix B

Quality of Included Studies According to the Joanna Briggs Institute Critical Appraisal Checklists

Analytical cross-sectional studies	Items1	2	3	4	5	6	7	8		Total score
Cabeças, 2007	N	Y	Y	—	—	—	Y	Y		4/8
Søgaard et al., 1996	Y	Y	Y	—	Y	N	Y	Y		6/8
Woods & Buckle, 2005	Y	N	Y	—	—	—	Y	—		3/8
Quasi-experimental studies	Items 1	2	3	4	5	6	7	8	9	Total score
Conner & Irwin, 2009	Y	Y	Y	N	N	—	Y	?	?	4/9^c
Hagner & Hagberg, 1989	Y	Y	Y	N	N	—	Y	Y	Y	6/9
Hopsu et al., 2000	Y	Y	Y	N	N	—	Y	?	Y	5/9^c
Kumar et al., 2005a	Y	Y	Y	N	Y	—	Y	?	—	5/9
Kumar et al., 2008	Y	Y	Y	N	N	—	Y	Y	?	5/9^c
Öhrling et al., 2012	Y	Y	Y	N	N	—	Y	Y	Y	6/9
Søgaard et al., 2001	Y	Y	Y	N	N	—	Y	Y	Y	6/9
Wallius et al., 2016	Y	Y	Y	N	N	—	Y	Y	Y	6/9

Note. Y = Yes; N = No; ? = unclear; — = not applicable. Low (score < 4), medium (score ≥ 4), high (scores > 6).

Conference proceedings.

Criteria for analytical cross-sectional studies: (1) Were the criteria for inclusion in the sample clearly defined? (2) Were the study subjects and the setting described in detail? (3) Was the exposure measured in a valid and reliable way? (4) Were objective, standard criteria used for measurement of the condition? (5) Were confounding factors identified? (6) Were strategies to deal with confounding factors stated? (7) Were the outcomes measured in a valid and reliable way? (8) Was appropriate statistical analysis used?

Criteria for quasi-experimental studies: (1) Is it clear in the study what is the “cause” and what is the “effect” (i.e., there is no confusion about which variable comes first)? (2) Were the participants included in any comparisons similar? (3) Were the participants included in any comparisons receiving similar treatment/care other than the exposure or intervention of interest? (4) Was there a control group? (5) Were there multiple measurements of the outcome both pre- and postintervention/exposure? (6) Was follow-up complete, and if not, was follow-up adequately reported and strategies to deal with loss to follow-up employed? (7) Were the outcomes of participants included in any comparisons measured in the same way? (8) Were outcomes measured in a reliable way? (9) Was appropriate statistical analysis used?

Acknowledgements

We are grateful to Tuulevi Ovaska, communications coordinator and information specialist at the University of Eastern Finland library, for her valuable contribution to search strategy development. No funding has been received for the review. The authors declare no conflicts of interest.

Mari-Anne Wallius is an occupational health physiotherapist and PhD candidate at the University of Eastern Finland in Kuopio. She received her MSc in health sciences (specialization: ergonomics) from University of Eastern Finland in 2015.

Susanna Järvelin-Pasanen is a university lecturer at the University of Eastern Finland. She received her PhD in health sciences from the University of Eastern Finland in 2014.

Saara M. Rissanen works as a postdoctoral researcher at the University of Eastern Finland. She received her PhD in medical physics from the University of Eastern Finland in 2012.

Pasi A. Karjalainen is a professor in image analysis and signal processing at the University of Eastern Finland, Kuopio. He received his PhD in medical physics from the University of Kuopio, Finland in 1997.

Kimmo Räsänen is MD, PhD and a professor of occupational health at the University of Eastern Finland in Kuopio. He received his PhD in occupational health from the University of Kuopio, Finland in 1998.

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