Unite Intervention Study
Transcript of Unite Intervention Study
The Effects of Ergonomic The Effects of Ergonomic Workstation Changes on Workstation Changes on Physical and Psychosocial Physical and Psychosocial Factors in Apparel Factors in Apparel ManufacturingManufacturing
Julianne Natale, Richard Wells, Mardon Frazer, Michael Kerr, Sue Ferrier, Syed Naqvi, Peter Subrata
University of WaterlooUniversity of Western Ontario, Institute for Work and Health,Occupational Health Clinics for Ontario Workers
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PurposePurpose• To compare physical and
psychosocial outcomes of workers who experienced ergonomic workstation changes in two clothing plants to their coworkers who did not
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The Clothing IndustryThe Clothing Industry• Prevalence of WMSDs in sewing
machine operators is higher than any other occupational group
• Sewing is highly repetitious, requiring substantial force and constrained postures
• Strong need for low-cost, quick solutions to reduce these risk factors
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Study IStudy I• Three clothing plants, 600 workers• Workstation changes made in two plants • Questionnaire administered before and
after ergonomic changes• Questionnaire: 16 variables measured
– Productivity– Pain intensity (Von Korff et al. 1992, Smith et al. 2001)– Impact of pain (WLQ: Lerner et al. 1997)– Fatigue on job (Borg 1990, Punnett 1997)– Job content (Karasek 1994, Kerr 2002)
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Measuring Pain IntensityMeasuring Pain IntensityUpper Upper BackBack
Right Shoulder Right Shoulder
Right Upper Right Upper ArmArm
Mid to Mid to Lower BackLower Back
Right Right ForearmForearmRight Right WristWristRight Right HandHand
Right Thigh
Right Lower Leg or Foot
NeckNeck
Left Left ShoulderShoulder
Left Upper Left Upper ArmArm
ButtocksButtocks
Left Left ForearmForearm
Left Left WristWrist
Left HandLeft Hand
Left Left ThighThighLeft Left Lower Lower Leg or Leg or
FootFoot
1=mild2=moderate3=severe4=unbearable
• Pain in last 7 days • Average pain in 6 months • Worst pain in 6 months
••NeckNeck••RUERUE••LUELUE••BackBack••RLERLE••LLELLE
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AnalysisAnalysis• Step I: repeated cross-sectional
analysis
2001 2003
Plant A
Plant B
Plant C
Determine within plant
differences at two time
periods
Participatory Change
Team
Consultant-TypeProcess
Referent
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Workstation ChangesWorkstation ChangesWorkstation Changes
Operations
•Table height adjusted•Table tilted•Chair height adjusted•Backrest adjusted•Large foot pedal installed•Footrest provided•Foot pedal location changed•Anti-fatigue matting provided•Buttonhole size changed•Supply rack lowered•Other
•Manual sewing machine operation•Parts inspect•Tie-up•Button & Iron
96 changes made 41 operators affected (in cohort)
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Manual Measurement: Manual Measurement:
01020304050607080
Shoulder Elbow Wrist Neck Trunk
BeforeAfter
Joints Measured
Aver
age
Join
t An
gle
(deg
rees
) *
*p<0.05
Sub-sample of 16 workstations
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Step I: ResultsStep I: Results
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Prod
Pain
Int
WLQ
-Tim
e
WLQ
-Phy
s
WLQ
-Men
&So
c
WLQ
-Out
Effo
rt
Fatig
ue-s
hldr
Fatig
ue-N
eck
Fatig
ue-B
ack
Fatig
ue-L
egs
Fatig
ue-F
i/W/F
o
Ove
ral E
ffort
JCQ
-DL
JCQ
-PD
JCQ
-PE
Plant APlant BPlant C
Questionnaire Variable
Nor
mal
ized
Mea
n (%
)
** *
*
*p<0.05
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AnalysisAnalysis• Step II: cohort of workers
Plant A
Plant B
Plant C
2001 2003
Analysis Original Employees
54%
75%
78%
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Step II: ResultsStep II: Results
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10Pr
od
Pain
Int
WLQ
-Tim
e
WLQ
-Phy
s
WLQ
-Men
&So
c
WLQ
-Out
Effo
rt
Fatig
ue-s
hldr
Fatig
ue-N
eck
Fatig
ue-B
ack
Fatig
ue-L
egs
Fatig
ue-F
i/W/F
o
Ove
ral E
ffort
JCQ
-DL
JCQ
-PD
JCQ
-PE
Plant APlant BPlant C
Questionnaire Variable
Nor
mal
ized
Mea
n (%
)
*
*p<0.05
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AnalysisAnalysis• Step III: cohort of workers sub-
grouped
Plant A
Plant B
Plant C
2001 2003
Analysis
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Step III: ResultsStep III: Results
Questionnaire Variable
Nor
mal
ized
Mea
n (%
) *
*p<0.05
No Change ParticipantsNo Change Participants
*
*
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Step III: ResultsStep III: Results
Questionnaire Variable
Nor
mal
ized
Mea
n (%
)
*p<0.05
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Prod
Pain
Int
WLQ
-Tim
e
WLQ
-Phy
s
WLQ
-Men
&So
c
WLQ
-Out
Effo
rt
Fatig
ue-s
hldr
Fatig
ue-N
eck
Fatig
ue-B
ack
Fatig
ue-L
egs
Fatig
ue-F
i/W/F
o
Ove
ral E
ffort
JCQ
-DL
JCQ
-PD
JCQ
-PE
Plant APlant B
*
*
Change ParticipantsChange Participants
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AnalysisAnalysis• Step IV: cohort of “change “workers
grouped across plants
Plant A
Plant B
Plant C
2001 2003
Analysis
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Step IV: ResultsStep IV: Results
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10Pr
od
Pain
Int
WLQ
-Tim
e
WLQ
-Phy
s
WLQ
-Men
&So
c
WLQ
-Out
Effo
rt
Fatig
ue-s
hldr
Fatig
ue-N
eck
Fatig
ue-B
ack
Fatig
ue-L
egs
Fatig
ue-F
i/W/F
o
Ove
ral E
ffort
JCQ
-DL
JCQ
-PD
JCQ
-PE
Difference
Questionnaire Variable
Nor
mal
ized
Mea
n (%
)
*
*p<0.05
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Study I ConclusionsStudy I Conclusions• Improvement in “Change” group
of workers– Productivity ratio
• Trend towards improvement in– WLQ-time, physical demands– Fatigue: shoulders, neck, fingers,
wrist, forearm– Psychological demands
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SummarySummary• After workstation adjustments and
changes:– only a small positive effect on posture
and RULA scores– an increased productivity ratio observed– trend to decreasing:
• WLQ-time and physical demands• Fatigue at: shoulders, neck, fingers, wrist,
and forearm
• Psychological demands
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Of Note…Of Note…• Interaction of productivity with
physical and psychosocial variables?– Piecework environment– “Ergonomic Pitfall”
• Process continuing with new participatory team at “Consultant” site (B)
• Qualitative analysis and further round of questionnaires in process