VU Research Portal
Effect of job rotation on need for recovery, musculoskeletal complaints, and sick leave
due to musculoskeletal complaints: a prospective study among refuse collectors
Kuijer, P.P.F.M.; van der Beek, A.J.; van Dieen, J.H.; Visser, B.; Frings-Dresen, M.H.W.
published in
American Journal of Industrial Medicine
2005
DOI (link to publisher)
10.1002/ajim.20159
document version
Publisher's PDF, also known as Version of record
Link to publication in VU Research Portal
citation for published version (APA)
Kuijer, P. P. F. M., van der Beek, A. J., van Dieen, J. H., Visser, B., & Frings-Dresen, M. H. W. (2005). Effect of
job rotation on need for recovery, musculoskeletal complaints, and sick leave due to musculoskeletal complaints:
a prospective study among refuse collectors. American Journal of Industrial Medicine, 47, 394-402.
https://doi.org/10.1002/ajim.20159
General rights
Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners
and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.
• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.
• You may not further distribute the material or use it for any profit-making activity or commercial gain
• You may freely distribute the URL identifying the publication in the public portal ?
Take down policy
If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately
and investigate your claim.
E-mail address:
vuresearchportal.ub@vu.nl
Download date: 09. Aug. 2022
AMERICAN JOURNAL OF INDUSTRIAL MEDICINE 47:394–402 (2005)
Effect of Job Rotation on Need For
Recovery, Musculoskeletal Complaints, and
Sick Leave Due to Musculoskeletal Complaints:
A Prospective Study Among Refuse Collectors
P. Paul F.M. Kuijer, PhD,
1,2
Allard J. van der Beek, PhD,
3,4
Jaap H. van Diee
¨
n, PhD,
2
Bart Visser, PhD,
2
and Monique H.W. Frings-Dresen, PhD
1
Background Job rotation might be an effective preventive measure to reduce the
prevalence of musculoskeletal complaints, although its effect has not been yet established.
The aim of the present study is to evaluate the effect of job rotation in refuse collecting on
need for recovery, prevalence of musculoskeletal complaints, and sick leave due to
musculoskeletal complaints.
Methods A 1-year prospective study among refuse collectors was performed, using
standardized questionnaires. Job rotation was performed between collecting two-wheeled
containers and driving a refuse truck. The experimental groups of rotating refuse collectors
at t
0
and t
1
(group R-R) and non-rotating refuse collectors at t
0
and rotating refuse
collectors at t
1
(group NR-R) were compared with a reference group of non-rotating refuse
collectors at t
0
and t
1
(group NR-NR).
Results The adjusted need for recovery of group R-R was marginally significantly lower
than need for recovery of the reference group. Groups R-R and NR-R had a more than two
times higher risk for complaints of the low back than the reference group. No other
significant results were found.
Conclusions Job rotation seemed to coincide with a reduced need for recovery and was
associated with an increased risk of low back complaints. No effects were found on sick
leave due to musculoskeletal complaints. The results might be influenced by the healthy
worker selection effect in the reference group and its inverse in the rotating groups. Am. J.
Ind. Med. 47:394–402, 2005.
ß 2005 Wiley-Liss, Inc.
KEY WORDS: job rotation; prevention; interventions; recovery; musculoskeletal
complaints; low back pain; sickness absence; occupational epidemiology; refuse
collecting
2005Wiley-Liss,Inc.
*Correspondence to:P.Paul F.M. Kuijer, Coronel Institutefor Occupational and Environmen-
tal Health, Academic Medical Center/University of Amsterdam, P.O. box 22700, 1100 DE
Amsterdam,The Netherlands. E-mail: p.p.kuijer@amc.uva.nl
Accepted 7 February 2005
DOI10.1002/ajim.20159. Published online in Wiley InterScience
(www.interscience.wiley.com)
1
Coronel Institute for Occupational and Environmental Health, AmCOGG Amsterdam Cen-
ter for Research into Health and Health Care, Academic Medical Center/Universityof Amster-
dam,The Netherlands
2
Institute for Fundamental and Clinical Movement Sciences,Faculty of Human Movement
Sciences,Vrije Universiteit Amsterdam,The Netherlands
3
Department of Public and Occupational Health,Institutefor Research in Extramural Med-
ic ine, VU University Medical Center, Amsterdam, The Netherlands
4
Department of Public
Health, Erasmus Universiteit Rotterdam,The Netherlands.
Contract grantsponsor:Dutch Health Research & Development Council/Medical Sciences
(ZonMw); Contract grant number: 97110120,8 SK/VB.
INTRODUCTION
Refuse collectors around the world are at a high risk for
the development of musculoskeletal complaints. Poulsen
et al. [1995] reported a nearly two times higher incidence rate
of musculosketelal complaints for refuse collectors in
Denmark than for the total Danish workforce. Verbeek
[1991] found that the incidence rate of disability for work
among refuse collectors in the capital of the Netherlands was
about four times higher than the rate among office workers of
the same refuse collecting company. A similar comparison
was made by Yang et al. [2001] for refuse collectors in
Taiwan. The risks for musculoskeletal complaints of the low
back and elbow/wrist among refuse collectors were more
than two times higher than those of their colleagues that
worked in the office. Two studies on occupational accidents
among refuse collectors in Brazil also stressed the high risk
for musculoskeletal complaints due to the high physical
workload [Pimenta Velloso et al., 1997; Robazzi et al., 1997].
In the United States of America, musculoskeletal injuries
make up about 80% of all workers’ compensation claims
among refuse collectors [Dorevitch and Marder, 2001].
Strains and sprains accounted for 44.5% of these claims.
About the same results were found in a study performed
among municipal refuse collectors in the state of Florida [An
et al., 1999]. A similar study performed in the capital of
Denmark reported that ‘‘overloading of the body’’ was the
third most important reason for occupational injury (18% of
the cases) [Ivens et al., 1998]. These studies stress the
importance of the introduction of preventive measures to
reduce the risk of musculoskeletal disorders in refuse
collecting [Kuijer and Frings-Dresen, 2004].
The high physical workload in refuse collecting is seen
as an important risk factor for these musculoskeletal
complaints and disorders [Kemper et al., 1990; Luttmann
et al., 1992; De Looze et al., 1995; Poulsen et al., 1995;
Frings-Dresen et al., 1995a; Schibye et al., 2001a; Kuijer
et al., 2003]. Therefore, interventions should be aimed at
reducing the physical workload by a reduction in physical
work demands. In many countries, domestic refuse is
collected by a team of a driver and one or more collectors
[Luttmann et al., 1992; Frings-Dresen et al., 1995a; Poulsen
et al., 1995; Robazzi et al., 1997]. The efficacy of job rotation
in refuse collecting has already been demonstrated. Two
previously performed studies showed that job rotation
resulted in a reduction of the physical work demands and
physical workload of refuse collectors working with
polythene bags and two-wheeled containers [Kuijer et al.,
1999; Kuijer et al., 2004]. Kuijer et al. [1999] described job
rotation between street sweeping, collecting polythene bags,
and driving a cleaning machine while Kuijer et al. [2004]
described job rotation between collecting two-wheeled
containers and driving a refuse truck. However, in both
studies the question remains whether the established
reduction in physical work demands and work load of the
refuse collectors outweighs the possible negative long term
health effect of the increase in work demands and physical
workload in the less strenuous job of driving of the cleaning
machine and the refuse truck, respectively. Therefore, the
effects of job rotation on musculoskeletal complaints and
sick leave due to these complaints should be established.
To the authors’ knowledge, no studies were performed
that actually evaluated the effect of job rotation on the
occurrence of musculoskeletal complaints. Only one study
reported possible health effects. In a study on the design of
check-out systems, Hinnen et al. [1992] found that job
rotation had a beneficial impact on the prevalence of
musculoskeletal disorders in cashier work with scanners.
This study indicates that job rotation might indeed be an
effective measure to reduce the prevalence of musculoske-
letal complaints.
Besides the prevalence of musculoskeletal complaints
and sick leave due to these complaints, need for recovery was
also assessed in the present study. Insufficient recovery is
seen as an important intermediate variable in the onset of
complaints [Kilbom, 1988; Sluiter et al., 2000]. It is
hypothesized that repeated insufficient recovery may start a
vicious cycle, in which extra effort has to be exerted at the
beginning of every new working period to prevent perfor-
mance breakdown. Eventually, this ongoing process may
lead to health complaints. Need for recovery appeared to be a
predictor of experienced health complaints among coach
drivers [Sluiter et al., 1999], and of job turnover in a study
among truck drivers [De Croon et al., 2004].
Therefore, the aim of this study was to evaluate the effect
of job rotation between refuse collecting and truck driving on
the need for recovery, the 12-month prevalence of muscu-
loskeletal complaints and sick leave due to musculoskeletal
complaints.
MATERIALS AND METHODS
Design and Study Population
A 1-year prospective study among male refuse collectors
working with two-wheeled containers was initiated in 1998.
Two measurements were performed: at baseline (t
0
) and after
1 year of follow-up (t
1
). To evaluate the effect of job rotation,
two groups were initially formed. The first group consisted of
employees who worked as non-rotating refuse collectors at t
0
and t
1
(group NR-NR). The second group consisted of
employees who rotated between refuse collecting and truck
driving at t
0
and t
1
(group R-R). During the present study, an
intermediate group was formed. This group consisted of
employees who were non-rotating refuse collectors at t
0
and
rotated between refuse collecting and truck driving at t
1
(group NR-R). Job rotation was performed during the day
and between days [Kuijer et al., 2004].
Effectiveness of Job Rotation 395
Information on the addresses of 24 companies employ-
ing these three groups, was derived from:
* A mailing to all the members of the Association for Waste
and Cleaning Management (NVRD) and the Association
of Dutch Waste Management Companies (VNA);
* An advertisement in the periodical of the NVRD;
* An appeal during a lecture held at the annual conference of
the NVRD;
* A telephone call to key members of the NVRD and VNA;
* Ad-hoc contacts with management and employees from
refuse collecting organizations.
All employees were requested to complete a question-
naire at t
0
and t
1
. The questionnaires were filled in at the office
of the refuse collecting organization. In deliberation with the
management, the employees filled in the questionnaires at the
beginning or at the end of the working day. This was mostly
done in a group session. A researcher was present to explain
the purpose of the study and to answer any questions
concerning the questionnaire. The researchers involved were
blinded to group membership: it was not known whether
participating refuse collectors rotated or not. A possibility
existed to fill in the questionnaire with the help of the
researcher. In this way, also employees with less fluency in
reading and/or writing could participate. When an employee
was not present, his manager was asked to hand over
the questionnaire (including a post-paid envelope) to the
employee. After filling it in, the employee could return
the questionnaire to his manager or send it directly to the
researchers.
One contacted company did not want to participate in the
study, in view of an ongoing reorganization. Therefore, the
first questionnaire was presented to 280 employees working
in 23 different companies. At t
0
, 243 (87%) questionnaires
were completed by 121 non-rotating participants and 122
rotating participants. At t
1
, three companies were no longer
willing to participate in the study (21 participants). Twenty-
five participants were no longer employed by the company.
Of the remaining 197 participants, 130 (66%) returned the
follow-up questionnaire. Of these 130 participants, 46
belonged to group NR-NR, 63 to group R-R, and 21 to group
NR-R.
Assessment of Independent
Variables
At t
0
and t
1
, the participants were requested to complete a
questionnaire concerning personal characteristics (age,
body height, body weight, the number of working years
at the company) and work demands (number of hours
collecting per week, number of hours driving per week,
number of working hours per week, number of working days
per week).
Assessment of Dependent Variables
Need for recovery, musculoskeletal complaints, and sick
leave due to musculosketelal complaints were also indivi-
dually assessed using the questionnaire at t
0
and t
1
. The need
for recovery was assessed using the 11-items dichotomous
scale as developed by Van Veldhoven and Meijman [1994].
An example of an item is ‘‘After a working day I am often too
tired to start other activities (Yes/No)’’ [Sluiter et al., 1999].
A total need for recovery was calculated for each employee.
The scores on the 11-items (1-0) were summed up and
transformed into a percentage of the maximum score,
ranging from 0 to 100.
To assess the 12-month prevalence of low back, neck,
shoulder, hand/wrist, and knee complaints a Dutch transla-
tion of the Standardized Nordic Questionnaire [Kuorinka
et al., 1987] was used. Sick leave due to musculoskeletal
complaints was assessed using one item [Burdorf et al.,
1996]. This item assessed whether or not the participant had
reported sick due to musculoskeletal complaints in the last
12 months. The need for recovery at t
1
, the 12-month
prevalence of musculoskeletal complaints at t
1
, and the
12-month prevalence of sick leave at t
1
were used as
dependent variables in separate analyses.
Analyses and Statistics
First, mean and standard deviation of the personal
characteristics (age, body height, body weight and number of
working years at the company) and work demands at t
0
(number of collecting hours per week, number of driving
hours per week, number of working days per week) of the
three groups were calculated. Besides, the mean and standard
deviation of the number of collecting hours per week and
number of driving hours per week were calculated at t
1
to
establish the effect of job rotation. Differences between
groups were tested using analysis of variance.
Second, a non-response analysis was performed. The
non-respondents at t
1
were compared with the respondents at
t
1
, classified according to the three groups and using the data
obtained at t
0
. Differences with respect to the personal
characteristics, musculoskeletal complaints, and sick leave
due to musculoskeletal complaints were tested using a t-test
and a Mann–Whitney U test for parametric and non-
parametric values, respectively.
Third, mean need for recovery, 12-month prevalence of
the musculoskeletal complaints, and 12-month prevalence of
sick leave due to musculoskeletal complaints at t
0
and t
1
were
calculated for the three groups. Next, crude mean difference
scores (DSs) and corresponding 95% confidence intervals
(CIs) were calculated for the need for recovery using analyses
of variance. Crude prevalence rate ratios (PRs) and
corresponding 95% CIs were calculated for the 12-month
prevalence of low back, neck, shoulder, hand/wrist, and knee
396 Kuijer et al.
complaints and 12-month prevalence of sick leave due to
musculoskeletal complaints using Cox’s proportional
hazards regression analysis with a constant risk period.
Cox’s proportional hazards regression analysis was per-
formed, because the prevalence of (sick leave due to)
musculoskeletal complaints was relatively high. For both
variables (DS and PR), the groups NR-R and R-R were
compared with the reference group NR-NR.
Finally, the effect of job rotation on the need for recovery
was controlled for possible confounding due to age at t
0
,
number of working hours per week at t
0
, and number of
working years in the company at t
0
(adjusted mean DS). The
effect of job rotation on (sick leave due to) musculoskeletal
complaints was controlled for potential confounding due to
age at t
0
, (sick leave due to) musculoskeletal complaints at t
0
,
number of working hours per week at t
0
, and number of
working years in the company at t
0
.
Job rotation may also have an effect on several
intermediate physical and psychosocial risk factors, such as
the time driving or decision authority. Therefore, these
variables were a priori not taken into account as potential
confounders on need for recovery and (sick leave due to)
musculoskeletal complaints.
Each of the independent variables was screened
separately for confounding. If the DS or PR of group NR-R
or R-R changed more than 10%, the variable was labeled as a
confounder and included in the multivariate model.
All statistical analyses were performed with version 8.0
of the SPSS statistical package and a significance level of 5%
was used.
RESULTS
Group Characteristics
Group NR-R was the youngest of the three groups with a
mean age of 29 years (Table I). The other two groups did not
significantly differ in age. No significant differences between
the three groups were found for the mean values of body
height, body weight, and number of years working at the
company.
The number of hours collecting and driving differed
substantially, as could be expected, due to the effect of job
rotation. The mean number of hours collecting per week at t
0
was 34, 31, and 15, for group NR-NR, NR-R, and R-R,
respectively. At t
1
the number of hours collecting for group
NR-R had changed to 18. The number of hours collecting per
week did not change between t
0
and t
1
for groups NR-NR and
R-R. The same effect was found for the number of hours
driving at t
0
and t
1
.Att
0
the number of hours driving per week
for the three groups was 1, 1, and 18, respectively. Due to the
introduction of job rotation, the number of hours driving per
week at t
1
was 19 for the group NR-R. Again, the number of
hours driving per week for the groups NR-NR and R-R did
not change between t
0
and t
1
. The three groups did not differ
on the number of working hours per week and the number of
working days per week, on average 41 and 5, respectively.
The mean need for recovery of the three groups did not
change between t
0
and t
1
(Table II). The 12-month
prevalences at t
0
and t
1
for complaints of the low back were
higher than for any other part of the body in all three groups.
TABL E I. Mean and Standard Deviation (SD) of the Personal Characteristi cs and the Work Demands
for the Non-rotating (NR-NR) and Rotating (NR-R and R-R) Dutch Refuse Collectors at t
0
*
Group NR-NR Group NR-R GroupR-R
n ¼ 46 n ¼ 21 n ¼ 63
Mean SD Mean SD Mean SD
Age (years) at t
0
34 9 29
#
637 9
Body height (m) at t
0
1.80 0.09 1.84 0.06 1.81 0.08
Body weight (kg) at t
0
79 13 78 14 8 6 12
Working years at company at t
0
875598
Collecting hours per week at t
0
34 8 31 7 15
#
5
Collecting hours per week at t
1
31
##
15 18 12 15 10
Drivinghours per week at t
0
131 518
##
9
Drivinghours per week at t
1
3
#
519 1320 12
Working hours per week at t
0
43 5 41 7 41 7
Working days per week at t
0
505150
NR-NR, non-rotating refuse collectors at t
0
and t
1
; NR-R, non-rotating refuse collectors at t
0
and rotating at t
1
;R-R,
rotating refuse collectors at t
0
and t
1
.
*The number of hours of collecting and driving at t
1
is presented for the three groups. Significant results are in bold type
(P < 0.05;
#
lower than the other two groups;
##
higher than the other two groups).
Effectiveness of Job Rotation 397
