419199
alAsia-Pacific Journal of Public Health
APHXXX10.1177/1010539511419199Mahmud et
The Effects of Office
Ergonomic Training on
Musculoskeletal Complaints,
Sickness Absence, and
Psychological Well-Being:
A Cluster Randomized
Control Trial
Asia-Pacific Journal of Public Health
XX(X) 1­–17
© 2011 APJPH
Reprints and permission: http://www.
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DOI: 10.1177/1010539511419199
http://aph.sagepub.com
Norashikin Mahmud, PhD, MSc, BA1,
Dianna T. Kenny, PhD, MA, BA (Hons)2,
Raemy Md Zein, BSc3, and Siti Nurani Hassan, BSc3
Abstract
This study explored whether musculoskeletal complaints can be reduced by the provision of
ergonomics education. A cluster randomized controlled trial study was conducted in which 3
units were randomized to intervention and received training and 3 units were given a leaflet.
The effect of intervention on knowledge, workstation practices, musculoskeletal complaints,
sickness absence, and psychological well-being were assessed at 6 and 12 months. Although
there was no increment of knowledge among workers, significant improvements in workstation practices in the use of monitor, keyboard, and chair were observed. There were significant
reductions in neck and upper and lower back complaints among workers but these did not
translate into fewer days lost from work. Workers’ stress was found to be significantly reduced
across the studies. In conclusion, office ergonomics training can be beneficial in reducing musculoskeletal risks and stress among workers.
Keywords
cluster randomized controlled trial, office ergonomics training, injury prevention, computer
user, musculoskeletal complaints, psychological well-being
Musculoskeletal complaints are commonly reported among office workers worldwide and these
can have detrimental effects on workers’ health and productivity.1,2 Factors that predict risk of developing musculoskeletal complaints can be divided into individual,3-5 ergonomic,6-9 and psychosocial
1
Program of Industrial Psychology and Organizational Psychology, Universiti Teknologi Malaysia, Malaysia
University of Sydney, Lidcombe, New South Wales, Australia
3
National Institutes of Occupational Safety and Health, Bangi, Malaysia
2
Corresponding Author:
Norashikin Mahmud, Faculty of Management and Human Resource Development, Universiti Teknologi Malaysia,
Johor, Bahru Campus, 81310 Skudai, Johor, Malaysia
Email: norashikin@fppsm.utm.my
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Asia-Pacific Journal of Public Health XX(X)
factors.10-13 The risk of developing musculoskeletal complaints is higher among workers who
have high work strain, longer mouse and keyboard use, perceived high muscle tension, previous
musculoskeletal complaints in the neck and shoulder, as reported by several longitudinal studies
with follow-up from 3 months to 5.4 years.14-19
Awareness and/or knowledge about the relationship between usage of computers and musculoskeletal complaints are essential to prevent them from becoming more severe. A study conducted in a French company reported that office and blue-collar workers had higher risk of
sickness absence due to upper limb disorders compared with managers and professionals.20 It
was also found in a population-based study in Sweden that respondents who reported concurrent
low back pain and neck and shoulder disorders were at high risk for short-term and long-term
sickness absence.21
In organizations, education/training is the best initial strategy in preventing occupational injuries.22,23 Training may also educate individuals from different managerial levels in the organization about office safety, which may simultaneously promote a culture of safety in the organization.
Previous studies conducted on the effectiveness of office ergonomic training reported improvements in knowledge, workstation habits, and reduction in musculoskeletal disorders. One study
used various educational interventions including posters, email, pictures on how to do stretching
and stress relief activities, workshops, and informational booklets. These interventions were
found to increase workers’ knowledge of cumulative trauma disorder and changes in the hand/
wrist and neck/shoulder postures when using computers.24 The other study conducted on workers
in a petrochemical research and development facility reported improvement in workstation configuration (mouse and head position) and symptom severity, but not in symptom reduction.25
Studies using different methods of ergonomics training have reported positive results. For example, those who received education programs such as participatory training (active learning session involving discussions and problem-solving exercises) and traditional training (lectures and
handouts) reported less pain/discomfort and positive perception of psychosocial work stress than
those who did not receive training.26 One study showed that both instructor-directed and selfdirected learning were effective in bringing about positive changes in ergonomics knowledge
and habits among workers.27 Another study, however, reported that training alone did not reduce
musculoskeletal symptom growth among respondents when compared with combining training
and adjustable chair as an intervention.28
The aim of the current study was to evaluate the effects of office ergonomics training compared
with no training on musculoskeletal complaints and psychological well-being in university-based
office workers. A cross-sectional survey had been previously conducted among the target group of
Universiti Teknologi Malaysia (UTM) office workers that assessed their awareness of office ergonomics and prevalence of musculoskeletal complaints. The findings indicated a low level of office
ergonomics awareness and high 12-month prevalence rates of musculoskeletal complaints in
shoulder (51.6%), neck (48.2%), and back (42.2%) regions.29 Results from the study suggested that
UTM staff were in need of office ergonomics training since they had not previously received any
formal training. To our knowledge, we could not find any study on preventive measures of musculoskeletal disorders among computer users in Malaysia, hence the need for this study. However, we
found only 2 articles on the prevalence and types of musculoskeletal disorders among office workers in Malaysia. A study conducted on clerical public servants reported 33% (95% confidence
interval = 28.8-37.3) prevalence of upper limb symptoms.30 The other study, which was conducted
among secretarial staff and undergraduate students, reported that poorer workstation ergonomics
increased the risk of developing neck, back, and wrist disorders.31
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Hypotheses
1.
2.
3.
4.
Office ergonomics training increases ergonomics knowledge.
Office ergonomics training improves workstation habits.
Office ergonomics training reduces musculoskeletal complaints among office workers.
Office ergonomics training can improve psychological well-being.
Methods
Study Design
Ethical approval to conduct the study was obtained from the University of Sydney Human
Research Ethics Committee. This study was designed as a 2-armed cluster randomized controlled trial. The experimental groups received office ergonomic training, and the control groups
were “business as usual” (no ergonomic training).
Participants and Setting
Office workers comprising staff from 6 units were invited to participate in the study. The inclusion criteria were those who were working with computers for at least 3 hours per day in either
permanent or contract employment. Those who had any previous illness and/or injuries as a
result of accidents and/or work hazards were excluded because these may have resulted in musculoskeletal disorders. We were only interested in musculoskeletal symptoms as a result of
computer use. The majority of the office workers sat in a cubicle; the size of the cubicle was
standardized, but it might have been smaller for several workstations because of space constraints. Each staff member had his/her own designated desk equipped with monitor (traditional
or flat screen), keyboard (traditional), and mouse (without wrist rest). The majority of workers
working in a cubicle had a keyboard tray (without a mouse tray) attached to the desk. Some, but
not all, workers not working in a cubicle had desks with a keyboard tray. In the case of workers
with no keyboard tray, the keyboards were placed on the desk. Most staff had their own telephone; however, a small number shared a telephone with coworkers (1:2). Chairs and desks
were adjustable, and staff had flexibility with respect to the movement of their keyboard and
mouse. Workstation layouts were generally consistent across units. There had been no serious
effort by management to upgrade these workstations ergonomically. Initial awareness of office
ergonomics was very low.29
Procedures
Ten units were identified, but only 6 units were included in the study. These 6 units were those
who were willing to participate. Letters of invitation were sent out to the management of units
to assign workers who were interested in participating in the study. A minimum number of 30
respondents from each unit were requested but more respondents were welcome as long as
numbers did not exceeded 35 people because of the training room capacity. Three units were
randomly assigned to the experimental group and 3 to the control group using a random number
table. The random number was set as 6. The minimum value was set as 1 (experimental group)
and maximum values as 2 (control group). The researchers were aware of the group allocation.
Respondents were aware of the study but they did not know whether they belonged to the
experimental or control group. Baseline questionnaires were distributed to respondents in the
intervention and control groups before training took place. Each respondent had a unique ID that
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Asia-Pacific Journal of Public Health XX(X)
can be identified by researchers only. Information from the baseline questionnaires assisted
researchers in determining the right respondents according to the inclusion criteria and rejected
those who fulfill the exclusion criteria. The intervention started in March 2009.
Respondents from the intervention groups received office ergonomics training. The in-house
ergonomics training was conducted by trainers from the National Institute of Safety and Health
(NIOSH). The training took place over a period of 1 day divided into 2 sessions and conducted
by 2 trainers. The first session was conducted in the morning (9.00 am to 1.00 pm) and consisted
of lectures on office ergonomics: understanding the relationship between office ergonomics and
the development of musculoskeletal discomforts, ergonomics improvements and adjustments of
workstations, and the importance of break and stretching exercises. The second session was
conducted in the afternoon (2.00 pm to 4.30 pm) and focused on the practical aspects of the training, in which trainers visited participants’ workstations and provided assistance on how to adjust
workstations effectively. The same trainers who participated in the workstation observation at
baseline conducted the observations; therefore, the interobserver bias was expected to be small.
We encouraged respondents to stay at their workstation in order for the trainers to help them
readjust their workstation if necessary. Trainers made suggestions on how to improve workstation practices but these were restricted to workstation furniture, equipment, and space available.
Respondents were also encouraged to participate in their workstation adjustments. Under some
circumstances, further suggestions were made on how to adjust the workstation and/or space.
The suggested changes would require support from management, for example, buying of new
furniture and equipment or allocation of more space. Respondents from the control groups received
a leaflet consisting of an office ergonomic diagram, tips on how to take a break, how to reduce
their workload, and stretching exercises. The experimental group also received the same leaflet
as the control group in addition to the ergonomic training.
Outcome Measures
We assessed outcomes at 6 and 12 months after training. The primary outcome measure was
self-reported musculoskeletal complaints. Respondents were asked whether they had experienced any aches, pains, discomfort, or numbness in any part of the body regions at any time
during the last 6 months as a result of working with a computer (yes or no). Data concerning the
prevalence of musculoskeletal complaints were gathered using the modified Nordic Questionnaire.32
Musculoskeletal complaints was measured based on 9 categories: neck, right and left shoulder,
upper and lower back, right and left upper limb (upper arm, elbow, lower arm, wrist, and fingers), and right and left lower limb (thigh/hip, knee, and feet). We combined right and left body
region as 1 entity, for example, right and left shoulder, as shoulder for analysis.
Office ergonomics knowledge, workstation habits, psychological well-being, and sickness
absence were the secondary outcome measures. Participants were asked about their office ergonomics knowledge in relation to the use of a monitor (eg, “I should place my monitor at arm’s
length away from me”), mouse (eg, “The mouse can be placed at any position as long as I can
reach it”), keyboard (eg, “The height of my keyboard should be at the same level as my elbow”),
chair (eg, “I only need a backrest on my chair if I have back pain”), and desk (eg, “My desk height
should be the same height as my elbow”). The questionnaire was developed by the researchers
based on a comprehensive literature search and consisted of 28 items. Respondents selected from
a 3-point scale that was coded as a binary variable: Agree = 1, Disagree = 0, and Don’t Know =0.
The total scores for different areas of ergonomics knowledge were calculated.
A sample of respondents’ workstation ergonomics habits was randomly selected for observation in each of the 6 departments/units at 2 weeks and 12 months follow-up. The observations
were conducted by 4 people from the NIOSH. Trial observations were conducted prior to actual
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Mahmud et al
observation of 2 office workers to make sure that trainers had a clear understanding of the workstation specification checklist and would use it reliably. The rating was either yes (if respondents
had correct workstation habits) or no (incorrect workstation habits). The interrater reliability
between the 4 observers was good (Cronbach α = .844). The checklist included items related to
the use of monitor (5 items), keyboard (7 items), mouse (2 items), chair (7 items), and desk (2
items), for example, monitor is at arm’s length away from user, keyboard at the right height
(elbow height), mouse is placed close to keyboard and within reach. The total scores for different
areas of workstation ergonomics were calculated.
Psychological well-being was measured using the DASS-21 (Depression, Anxiety, and
Stress) questionnaire.33 DASS-21 was chosen because of its ability to measure psychological
distress in general34 and because of its frequent use in clinical and nonclinical settings.34-36 A
translated and validated Bahasa Malaysia version was used to measure symptoms of depression,
anxiety, and stress.37 DASS-21 was divided into 3 negative emotional states consisting of depression (7 items), anxiety (7 items), and stress (7 items). The depression scale contains psychological
symptoms such as devaluation of life, hopelessness, lack of interest, self-deprecation, anhedonia,
dysphoria, and inertia. On the other hand, the anxiety scale measured skeletal musculature
effects, autonomic arousal, subjective experience of anxious effect, and situational anxiety,
whereas stress scales consisted of psychological symptoms, for example, easily upset, irritable
or overreactive, difficult to relax, and nervous arousal. Respondents were asked to evaluate their
feelings based on a 4-point scale (0 = Did not apply to me at all, 1 = Applied to me to some
degree or some of the time, 2 = Applied to me a considerable degree, or a good part of the time,
3 = Applied to me very much, or most of the time). Since we are using DASS-21, the total score
for each emotional symptom obtained is multiplied by 2. Higher scores indicate higher levels
depression, anxiety, or stress. The mean score for the normative sample for depression is 6.34 ±
6.97, anxiety 4.70 ± 4.9, and stress 10.11 ± 7.9.
Sickness absence was assessed at baseline and postintervention by 2 items: “In the last 6 months,
how many days (approx.) in total have you had off work due to work-related musculoskeletal complaints?” and “In the last 6 months, how many separate times have you had time off work due to
work-related musculoskeletal complaints?” An average number of days and episodes of sickness
absence were calculated.
Statistical Analyses
We conducted intention-to-treat analysis in which respondents were considered exposed to the
intervention assigned to them, that is, training and workstation adjustments. The between-group
differences for office ergonomics knowledge and workstation habits were calculated from the
differences of mean scores of correct answers and ergonomics habits in the monitor, keyboard,
mouse, chair, and desk use; ANOVA test analysis was used to analyze the significant differences
between groups. Analysis of repeated-measures ANOVAs was used to determine the effects of
training on musculoskeletal complaints, sickness absence, and psychological well-being (DASS-21).
Difference scores were used for analysis if there were significant differences at baseline.
Results
Baseline Results for Demographic and Occupational Characteristics
The demographic and occupational characteristics of the study population at 6-month follow-up
are presented in Table 1. The baseline characteristics between the 2 groups were essentially
similar with respect to age, gender distribution, body mass index, and workplace characteristics.
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Asia-Pacific Journal of Public Health XX(X)
Table 1. Demographics and Occupational Characteristics of Study Population at 6-Month Follow-up
Training Group
(n = 43), Mean or %
Personal Characteristics
Age
Gender
Male
Female
BMI (µ (SD; range))
Male
Female
Education
High school (SRP/SPM)
Technical certificate/diploma
Degree (bachelor’s/post-degree)
Other
Hand use to operate computer
Right
Left
Exercise per week
No
Yes
Years of working using computer
Hours sitting using computer
Hours typing
Days of sickness absence
Episodes of sickness absence
34.6 (10.4)
30.2%
69.8%
Control Group
(n = 55), Mean or %
34.2 (8.4)
20%
80%
23.8 (3.0)
22.9 (4.7)
25.9 (5.8)
22.9 (3.6)
58.1%
23.3%
9.3%
9.3%
90.7%
9.3%
29.1%
32.7%
30.9%
7.3%
92.7%
7.3%
30.2%
69.8%
10.4 (6.9)
6.6 (1.6)
5.1 (1.9)
0.26 (0.6)
0.26 (0.6)
58.2%
41.8%
11.2 (6.8)
6.9 (1.4)
5.2 (1.9)
0.78 (1.6)
0.58 (1.4)
Abbreviation: BMI, body mass index.
However, a greater number of respondents in the control group completed higher education and
exercised less than the training group.
Response Rate
A total number of 89 respondents attended training and 69 (77.5%) returned baseline questionnaires.
The response rate for 6 and 12 months were 58 (68.2% and 71.6%). There were 90 respondents
in the control group with a response rate of 65 (72.2%) at baseline, 70 (77.8%) at 6 months, and
69 (77.5%) at 12 months. The number of dropouts because of resignation from UTM was 1.1%
in the control group and 8.9% in the training group. Respondents who provided data at baseline
and postintervention were included in the analyses. The total number of respondents included in
the analysis was 42 for the training group and 50 the for no training group. The flow of the study
is presented in Figure 1.
Office Ergonomics Knowledge
The results show that there was only 1 significant difference in knowledge for either group over
time. This occurred in the control group where knowledge about mouse use decreased over time
(Table 2).
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Mahmud et al
Assessed for eligibility (n=10 units)
Excluded
(n = 4 units)
Enrolment
Randomized (6 units)
Baseline
Received training
Unit = 3 (89 participants)
Return questionnaires (n = 69)
No training
Unit = 3 (90 participants)
Return questionnaires (n = 65)
6 months
Return questionnaires (n = 58)
Maternity leave = 1
Resigned = 3
Excluded because of
health problem = 1
Return questionnaires (n = 70)
Maternity leave = 1
Resigned = 1
12 months
Return questionnaires (n = 58)
Maternity leave = 1
Resigned = 4
Return questionnaires (n = 69)
Figure 1. Study flow diagram
Table 2. Means (Standard Deviations) of Office Ergonomics Knowledge for Training and Control Groups
at Baseline and 6 and 12 Months Follow-up
Training Group
Control Group
Ergonomics
knowledge
Baseline
6 Months
12 Months
P Value
Baseline
6 Months
12 Months
P Value
Monitor (n = 6)
Keyboard (n = 10)
Mouse (n = 5)
Chair (n = 5)
Desk (n = 2)
1.8 (1.5)
2.4 (2.0)
2.3 (1.3)
1.3 (1.2)
0.6 (0.8)
1.9 (1.3)
2.3 (1.5)
2.7 (0.9)
1.5 (1.2)
0.6 (0.8)
1.9 (1.3)
2.3 (1.4)
2.5 (1.1)
1.7 (1.3)
0.7 (0.7)
.901
.941
.293
.349
.841
1.6 (1.2)
2.1 (1.5)
2.7 (0.9)
1.5 (1.1)
0.5 (0.7)
1.4 (1.0)
2.3 (1.7)
2.8 (0.9)
1.3 (0.9)
0.3 (0.6)
1.2 (0.9)
1.9 (1.3)
1.9 (1.2)
1.3 (1.1)
0.4 (0.7)
.165
.568
<.0001
.445
.562
Workstation Habits
There were significant improvements in the use of monitor, keyboard, and chair among workers
at 12-month follow-up (Table 3). The results from post hoc analysis showed the following: for
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Asia-Pacific Journal of Public Health XX(X)
Table 3. Means (Standard Deviations) of Workstation Habits for Training and Control Groups at
Baseline and 2 weeks and 12 Months Follow-up
Training Group
Workstation
Ergonomics
Baseline
(n = 30)
2 Weeks
(n = 25)
12
Months
(n = 27)
Monitor (n = 5)
Keyboard (n = 7)
Mouse (n = 2)
Chair (n = 7)
Desk (n = 2)
3.3 (1.0)
3.9 (2.2)
0.8 (0.8)
3.8 (1.4)
1.5 (0.6)
3.8 (1.0)
5.4 (1.6)
1.2 (0.8)
5.7 (1.3)
1.8 (0.4)
4.3 (1.1)
6.1 (1.2)
1.3 (2.1)
5.5 (1.2)
1.6 (0.7)
Control Group
P value
Baseline
(n = 30)
2 Weeks
(n = 23)
12
Months
(n = 34)
P Value
.002
<.0001
.256
<.0001
.138
2.6 (1.3)
3.7 (1.9)
0.8 (0.7)
3.9 (1.9)
1.4 (0.6)
2.7 (0.9)
3.2 (1.5)
0.5 (0.6)
3.9 (1.7)
1.7 (0.4)
2.6 (1.0)
3.4 (1.9)
0.6 (0.7)
3.7 (1.5)
1.7 (0.5)
.826
.467
.321
.867
.138
80
70
60
Neck
50
Training
No training
40
30
20
10
0
Baseline
6
months
12
months
Figure 2. Percentage of neck complaints at baseline and 6 and 12 months follow-up (yes or no)
monitor, there was a significant improvement from baseline to 12 months (P = .002). For keyboard and chair, there were significant improvements from baseline to 6 months (P = .002 and
P < .0001, respectively) and from baseline to 12 months (P ≤ .0001 and P ≤ .0001, respectively).
In contrast, there were no significant differences in the control groups at follow-up.
Self-Reported Musculoskeletal Complaints
There was a reduction of musculoskeletal complaints at 12 months for all body regions except
for left upper limb regions. There were significant interactions between groups across time for
neck (Figure 2), upper back (Figure 3), and lower back (Figure 4) complaints. There were significant main effects between groups for all body regions. The summaries of repeated-measures
ANOVA are presented in Table 4. Respondents in the control group consistently reported an
increase in discomfort in the neck, upper back, right and left upper limb, lower back, and right
and left lower limb. The reported discomfort was consistent for left shoulder at all 3 times, and
there was a smaller decrease in discomfort for right shoulder at 6 months. Overall, there were
no significant differences of musculoskeletal discomforts over time in the control group.
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Mahmud et al
60
Upper back
50
40
Training
30
No training
20
10
0
Baseline
6
months
12
months
Figure 3. Percentage of upper back complaints at baseline and 6 and 12 months follow-up (yes or no)
60
Lower back
50
40
Training
30
No training
20
10
0
Baseline
6
months
12
months
Figure 4. Percentage of lower back complaints at baseline and 6 and 12 months follow-up (yes or no)
Number of Days and Episodes of Sickness Absence
There were no significant interactions between groups over time for the number of days and
episodes of sickness absence in the training and control groups (Table 5 and Figures 5 and 6).
Psychological Well-Being (DASS-21)
Repeated-measures 1-way ANOVA revealed a significant decrease in depression, anxiety, and
stress symptoms in the training group (Table 6). The means of the depression and anxiety scales
were more significantly reduced after the training when compared with before the training
(Figures 7 and 8). The mean for the stress scale decreased at 6 months and remained lower at 12
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F = 22.882 (P ≤ .0001)
F = 9.228 (P = .003)
F = 6.040 (P = .016)
F = 5.934 (P = .017)
F = 9.425 (P = .003)
F = 13.467 (P = <.0001)
F = 8.638 (P = .004)
F = 6.590 (P = .012)
F = 8.069 (P = .006)
F(1.900) = 2.404 (P = .096)
F(1.903) = 2.302 (P = .106)
F(2) = 0.097 (P = .907)
F(2) = 0.565 (P = .569)
F(2) = 1.225 (P = .296)
F(2) = 1.316 (P = .271)
F(2) = 1.120 (P = .329)
F(2) = 1.489 (P = .228)
F(2) = 1.867 (P = .158)
Neck
Right shoulder
Left shoulder
Upper back
Right upper limb
Left upper limb
Lower back
Right lower limb
Left lower limb
Abbreviations: CG, control group; TG, training group.
Main Group Effect
Main Time Effect
CG > TG (P ≤ .0001)
CG > TG (P = .003)
CG > TG (P = .016)
CG > TG (P = .017)
CG > TG (P = .003)
CG > TG (P ≤ .0001)
CG > TG (P = .004)
CG > TG (P = .012)
CG > TG (P = .006)
Contrast Analyses
Between-Subjects Effects
Musculoskeletal
Complaints
Within-Subjects Effects
Table 4. Repeated-Measures Analyses of Variance for Self-Reported Musculoskeletal Complaints
F = 5.289 (P = .024)
F = 1.936 (P = .168)
F = .411 (P = .523)
F = 4.956 (P = .028)
F = 2.366 (P = .127)
F = 1.202 (P = .276)
F = 5.563 (P = .021)
F = 2.422 (P = .123)
F = 1.618 (P = .207)
Group * Time Effect
Interaction Effects
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Mahmud et al
Table 5. Results of Repeated-Measures Analyses of Variance for the Number of Days and Episodes of
Sickness Absence Using Difference Scores
Within-Subjects Effects
Between-Subjects
Effects
Interaction Effects
Main Time Effect
Main Group Effect
Group * Time Effect
F(1.161) = 0.039 (P = .876)
F = 1.162 (P = .284)
F = 0.001 (P = .978)
F(2) = 0.020 (P = .981)
F = 0.326 (P = .569)
F = 1.813 (P = .182)
Sickness
Absence
Number of days
of sickness
absence
Episodes of
sickness
absence
Days of sickness absence
0.9
0.8
0.7
0.6
0.5
Training
0.4
No training
0.3
0.2
0.1
0
Baseline
6
months
12
months
Episodes of sickness absence
Figure 5. Means for days of sickness absence at baseline and 6 and 12 months follow-up
0.7
0.6
0.5
0.4
Training
0.3
No training
0.2
0.1
0
Baseline
6
months
12
months
Figure 6. Means for episodes of sickness absence at baseline and 6 and 12 months follow-up
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Asia-Pacific Journal of Public Health XX(X)
Table 6. Results of Repeated-Measures Analyses of Variance for Depression, Anxiety, and Stress
(DASS-21)
Within-Subjects Effects
Between-Subjects
Effects
Interaction Effects
DASS-12
Main Time Effect
Contrast Analyses
Main Group Effect
Group * Time Effect
Depression
F(1.921) = 8.043
(P = .001)
F(2) = 5.024
(P = .008)
F(2) = 12.859
(P ≤ .0001)
T1 > T2 (P = .003);
T1 > T3 (P = .001)
T1 > T2 (P = .021);
T1 > T3 (P = .004)
T1 > T2 (P ≤ .0001);
T1 > T3 (P ≤ .0001)
F = 0.065
(P = .800)
F = 0.190
(P = .664)
F = 0.007
(P = .935)
F = 2.119
(P = .149)
F = 2.943
(P = .090)
F = 8.783
(P = .004)
Anxiety
Stress
Abbreviations: DASS-12, Depression Anxiety Stress Scales–12; T1, baseline; T2, 6-month follow-up; T3, 12-month follow-up.
8
7
Depression
6
5
Training
4
No training
3
2
1
0
Baseline
6
months
12
months
Figure 7. Means for depression at baseline and 6 and 12 months follow-up
The maximum possible score for depression is 42 and higher score indicates more symptom severity.
10
Anxiety
8
6
Training
4
No training
2
0
Baseline
6
months
12
months
Figure 8. Means for anxiety at baseline and 6 and 12 months follow-up
The maximum possible score for anxiety is 42 and higher score indicates more symptom severity.
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Mahmud et al
12
10
Stress
8
Training
6
No training
4
2
0
Baseline
6
months
12
months
Figure 9. Means for stress at baseline and 6 and 12 months follow-up
The maximum possible score for stress is 42 and higher score indicates more symptom severity.
months after training (Figure 9). A significant interaction across time periods was found for the
stress scale (P = .004).
Discussion
Office ergonomics training as the primary injury prevention program has beneficial effects on
workstation practices, lower musculoskeletal risks, and reduced stress among computer users.
Although there was no significant improvement in knowledge over time among respondents
who received training, training did have an impact on behavioral changes. We observed
improvements in workstations habits with respect to how workers used their monitor, keyboard,
and chair. The largest improvements were in the position of monitor and keyboard; workers’
body posture in elbow, forearms, upper arms, wrists, and shoulders when typing; and workers’
body posture for lumbar support, thighs, knees, and feet while sitting. These findings are supported by other studies showing that training improves computing body postures and workstation ergonomics practices.27,38-40 Our study showed that the training session, the help and
guidance given by trainers, and the active participation of workers in their workstation adjustments were effective in improving workstation ergonomics practices.
The improvement in workstation habits benefited workers in terms of having good computing
body postures and techniques for using computers, which may lower the risk of future musculoskeletal disorders. There was a significant reduction of complaints in the neck and upper and
lower back among workers in training group over time. The results indicate that training in the
correct interaction with one’s workstation may have significant benefits to workers in terms of
their musculoskeletal well-being. Evidence-based accessible guidelines and appropriate training
should be available to all workers. Previous studies have reported that training alone was less
effective in reducing musculoskeletal complaints if workers were not provided with appropriate
equipment to implement their new ergonomic knowledge. Two studies, one combining training
and adjustable chairs28 and the other combining training with a flexible workstation41 reported
lower musculoskeletal disorders among workers compared with those who received training and
flexible workspace only. This study was limited in that it was unable to include the quality of the
work environment or to provide more ergonomically appropriate workstations to participants.
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Asia-Pacific Journal of Public Health XX(X)
Nonetheless, this study has shown that improvements in musculoskeletal complaints can be
achieved with a simple, cost-effective training program.
The positive impact of the workstation adjustment and the reduction of musculoskeletal complaints could be explained with reference to the health behavior model commonly used in health
education and health promotion.42 This model suggests that behavioral change is determined by an
individual’s perception of the disease and the difficulty of the strategies needed to decrease it.43
According to this model, the perceived health threat would direct the individual toward healthy
behavioral change. For example, respondents who attended the office ergonomics training were
given information regarding the association between office ergonomics and the risk of having
musculoskeletal complaints and the intervention strategies to reduce them. As a result, they
would be able to identify the threat and/or be made aware of the seriousness of the symptoms if
they remained untreated. The individual’s willingness and ability to change his or her health
habits based on the interventions may influence willingness to change health behaviors and
maintain the changed behavior. However, this would only take place if the respondents realized
the benefit to health of behavioral change. Although barriers to behavioral change were not assessed,
it is likely that they would affect the change process as outlined in the model. In addition, the
influence from the external and internal factors may also influence the success of behavioral
change, for example, advice from others, mass media campaigns, and one’s own belief (self-efficacy)
as to whether one can make the changes,44 may also influence the success of the intervention.
Future studies need to look deeper into the contribution of these factors to provide more information on the effectiveness of education health program on health.
There were no significant differences in sickness absence in the training group when compared with the control group. We could not comment on the lack of significant findings because
we only measured reduction in complaints’ frequency (yes vs no). Further exploration is needed
as to why reduced musculoskeletal complaints in visual display unit operators did not result in
fewer days lost from work. Nevertheless, workers in the training group reported reduced symptoms of stress across time compared with the control group. The majority of workers in the training group reported normal level of stress symptoms, and the mean was above the normative
sample at baseline; the levels of improvement after intervention were not clinically significant.
Despite this fact, the findings concurred with those of Bohr,26 who reported that ergonomics
training reduces psychosocial work stress among those who receive participatory education.
Bohr was not sure whether the improvement in the work area configuration or worker postures
resulted in the decrease of psychosocial work stress, although earlier studies conducted on the
association between stress and work-related musculoskeletal disorders demonstrated an association.45,46 The causal relationship between both is still unclear in the epidemiological field.47
Therefore, more studies are needed to explore the causal relationship between musculoskeletal
disorders and occupational stress.
Limitations
Sample size calculation was not conducted because of the conduct of the study in a naturalistic
setting. Thus, we could not determine study statistical power with respect to the mean value
differences between 2 clusters. The number of respondents who were included in the analysis
was small because we only included those who had the same ID. We did not measure the severity and duration of pain as one of the primary outcome measures. Contamination between individuals from the same clusters may influence the effect of outcomes. In addition, transfer of
knowledge between clusters might have occurred during social interactions and/or during attendance at courses since workers were from the same geographical area but in different locations
(ie, buildings). The sample size was not large enough to adjust for the effect of possible
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Mahmud et al
confounders. The strength of our study was the randomization of groups to intervention and
control groups, which is the most efficient way to control for the effects of known and unknown
confounders. Although blinding of respondents is desirable in randomized controlled trials to
reduce potential responder and observer biases, it is often not achievable in field-based studies
such as the study reported here.
Conclusions
We reported on a preliminary study to determine the effectiveness of office ergonomics training
to reduce musculoskeletal complaints in UTM. We found that office ergonomics training
improved workstation habits, reduced musculoskeletal complaints, and reduced psychological
well-being among office workers but the impact was small. We hope that the results may benefit UTM staff as the management is made aware that inexpensive ergonomics training has a
positive impact on the safety and health of office workers. University management can actively
participate in both training and investment in adjustable furniture for office workers. Further
research combining training and use of adjustable furniture in UTM is recommended in the
future.
Acknowledgments
The authors thank each participating unit/department that participated in the study and also Associate
Professor Dr Maketab bin Mohamed, the Director of Occupational Health and Safety Unit, Universiti
Teknologi Malaysia, who supported our study. We also would like to thank trainers from NIOSH who
conducted workstation observations. We also thank Dr Robert Heard and Dr Roger Adams, Sydney
University, for helpful comments on the statistical analyses.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or
publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
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