We found no change in MSDs, except for shoulder complaints,
and no relation between an increase in the use of ergonomic
measures and a decrease in MSDs of the lower back, knees, and
shoulders. We explored an alternative approachdRR for using ergonomic
measures [i.e., now and then; regularly; often; and
(almost) always] versus not using ergonomic measures [i.e.,
(almost) never] and a “decrease of MSD” versus “no decrease of
MSD”dbut no statistically significant RRs were found for any of the
MSDs. Not finding an effect of an increase in the use of ergonomic
measures might be due to a lack of reduction on MSD risks (as
construction work is characterized by multiple ergonomic stressors
to multiple bodily regions), the relatively short time of follow-up or
small attributional fraction of work exposures [13]. The fact that a
substantial proportion of the workers indicated that their MSDs
were not work related (31%) suggests that MSDs will not be affected
by a change in the physical work load alone. In addition, half of the
workers indicated that their complaints worsened because of their
work and that they experienced limitations in their work, therefore
the number of workers who are likely to gain most by increasing
their use of ergonomic measures is limited. Finally, it should be kept
in mind that workers could change their working technique (e.g.,
lifting technique) as a result of an ergonomic intervention and
thereby reduce the potential positive effect on bodily structures
[14]. As previously reported by van der Molen et al [10], other aspects
should be considered when interpreting and explaining the
findings: (1) the number of construction workers who use ergonomic
measures (almost) always was limited and thereby the effect
on MSDs is likely to be limited too; (2) the preventive effect of using
ergonomic measures on MSDs in general might be limited and vary
among the nine occupations and among younger and older
workers; (3) owing to the episodic character of MSDs, the two time
points of measurement in 2 years in combination with the 6-month
recall period might be too limited to fully capture the scope of the
MSD problem; and (4) limited statistical power could have masked
evidence for effects or relationships, although the estimate of the
risks are around 1, and the differences in MSDs between the
workers using ergonomic measures and those not using ergonomic
measures are therefore small.