identifying musculoskeletal injuries
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Identifying Ergonomic Risk Factors to PreventFactors to Prevent
Musculoskeletal Injuriesin Agriculture
Debra Milek, MD, PhD, MPH
Medical Director, Occupational and Environmental Medicine Clinic at Harborview, EHS & COHE, UW
di iMedicineAssociate Professor, UW DEOHS
FARMWORKERS ARE AT RISK FATAL AND NON‐FATAL INJURIES WMSD (Work‐related musculoskeletal disease)WORK RELATED LUNG DISEASE WORK‐RELATED LUNG DISEASE
NOISE‐INDUCED HEARING LOSS SKIN DISEASES SKIN DISEASES CANCERS CHEMICAL EXPOSURE RELATED ILLNESSES (e.g. ( gPESTICIDES)
HEAT RELATED ILLNESSESEYE INJURIES EYE INJURIES
AGRICULTURE IS A DANGEROUSAGRICULTURE IS A DANGEROUS LINE OF WORK
AMONG THE MOST DANGEROUS 2011: 570 AG WORKERS DIED FROM WORK‐ RELATED INJURIES (7X HIGHER THAN PRIVATE INDUSTRY)INJURIES (7X HIGHER THAN PRIVATE INDUSTRY)
2011: INJURY RATE 40% HIGHER THAN IN ALL WORKERS (CROP AND ANIMAL PRODUCTION) Injury rates are highest among children age 15 and under and adults
EVERY DAY ~243 AG WORKERS SUFFER SERIOUS LOST TIME INJURY 5%PERMANENT IMPAIREMENTTIME INJURY, 5%PERMANENT IMPAIREMENT
Agricultural Injuries : ACUTEAgricultural Injuries : ACUTE TRAUMATIC EVENTS
Rollovers When Rollover Protective Structures and Seatbelts
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Marked decrease with above use
FallsFalls Photos from OSHA Youth In Agriculture
FALLS Most common accident in ag (29% of claims) Orchard workers have the most WC ag claims Orchard workers have the most WC ag claims More than 200/yr associated with ladders
Tipping or slipping Average OOW = 150 day
Efforts include better safety training, sensors on ladders, shorter d bil l f htrees and mobile platform approaches
Photo OSHA Youth in agriculturePhoto OSHA Youth in agriculture
Bandit Xpress harvest demonstrationp
WMSD in Agriculture Workers FAR EXCEEDS OTHER AG ILLNESSES OR INJURIES
BACK NECK SHOULDERS KNEES
ARE AMONG THE MOST COMMON AREAS INJURED
WMSD Physical Risk Factors inWMSD Physical Risk Factors in Agriculture
Heavy lifting and carrying –magnitude, velocity and frequencyA k d i i f i i k Awkward position of extremities or trunk Stooping, reaching overhead
R titi Repetition Clipping, cutting, picking
Prolonged static postures Prolonged static postures Vibration
Other WMSD Risk Factors inOther WMSD Risk Factors in Agriculture
Piece‐rate payment Seasonal work May not speak or understand English
May not be aware of safety issues, standards, rights i d i l h d d Not trained in a language they understand
Farm owners may be less familiar with modified duty
I j i /Di Lik lInjuries/Disease Likely UnderestimatedUnderestimated
Data sources are poor Small farms may also be exempt (farms less than 11 employees)Mi d l k b d b Migrant and seasonal workers may not be covered by workers’ compensation (states)
Few to no surveillance programs Few to no surveillance programs Research and pilots limited to small numbers Few studies Few studies
What Else Do We Know?
OBSTACLES TO REPORTING INJURY:
Family members Migrant workers may not report injury for fear of retaliation or concerns if undocumented Ma not ha e access to legal ser ices May not have access to legal services
Primary prevention Prevent workplace injuries and illnessesy p eve o eve wo p ce ju es d esses
Secondary prevention Prevent disability among workers with work-related injuries and illnesses
Tertiary prevention Manage disability to reduce residual deficit and dysfunction
Ergonomics “The applied science of fitting tools and tasks to the persons performing them in such a way that the strengths of the human body and psychology are strengths of the human body and psychology are maximized and exposure of weaknesses to stressors is minimized”.
• National Ag Safety Database
Ergonomics Fitting the work to the worker, instead of vice versa
Agricultural Ergo Challenges Workplaces and tasks vary by season, commodity, geography, production method = hundreds of distinct situations and work processessituations and work processes
Paucity of applicable solutions transferrable to ag pruning weeding harvestingpruning, weeding, harvesting Requires individual solutions
Funding (little for engineering research in ag ergo)g ( g g g g )
A i lt l E Ch llAgricultural Ergo Challenges Concept that wear and tear is a necessary part of doing Concept that wear and tear is a necessary part of doing business
Field trials of proven concepts needed for individual p pcrop/commodity
Portable power systems for use in field, trees, and awkward situations are needed
Small market niche isn’t attractive profit wise for existing technology companies to re toolexisting technology companies to re‐tool
Caveats for Ag Ergo Doesn’t decrease productivity Doesn’t decrease comfort, safety or health Doesn’t create new problems Doesn’t have an unworkable cost benefit ratio Doesn’t displace the worker
BASIC ERGO PRINCIPLESMAINTAIN NEUTRAL POSTURE—MUSCLES AT RESTING LENGTH AND JOINTS ARE NATURALLY ALIGNEDALIGNED
MAXIMUM CONTROL AND FORCE MINIMUM STRESS MINIMUM STRESS
Figure 4. Neutral and awkward back postures.
Th f ll i d t ti d i d t hi hli ht th ff t th t k d The following demonstrations are designed to highlight the effect that awkward postures have on muscle activity for the wrist, elbow, shoulder, and lower back. (NIOSH)
Figure 3. Neutral and awkward shoulder postures. (NIOSH)
WORK IN THE POWER/COMFORT ZONE
MINIMIZE EXCESSIVE REACH AND MAINTAINING NEUTRAL POSTURE
ERGO PRINCIPLE: REDUCE EXCESSIVE FORCEEXCESSIVE FORCE
INCREASED FORCE INCREASES THE RISKO A G A SOF FATIGUE AND WMSD
Some SuccessMostly in areas of lifting and carrying loads awkward and static positions loads, awkward and static positions LighteningChanging handling technologiesDolliesDolliesRe‐positioning
One Solution:U ll li h b ( h i h ) h h dd i d i h Use a smaller, lighter tub (on the right) that has add‐on grips and weighs an average 46 pounds when full.
POOR HANDLE DESIGN
Poorl designed load No handles and Better designed load Handles are pro ided Poorly‐designed load: No handles, and load must be carried too far from the body.
Better‐designed load: Handles are provided and the load is closer to the body.
Problem:Carrying heavy boxes by hand is strenuous
One Solution:Roll a stack of boxes with a hand pallet truck.y g y y
and awkward.• Carrying loads up to 75+ pounds is tiring.• Can only move four boxes at once.• Awkward carrying positions
• Carry loads of 500+ pounds with less effort.• Can move up to 16 boxes at once.• Allows loads to be rolled.• Less stooping bending and lifting• Awkward carrying positions.
• Must stoop, bend, and lift often.• Poor handles on boxes.
• Less stooping, bending, and lifting.• Better carrying grip, lower weight athandles.
One Solution:Problem:Washing leafy greens by hand is backbreakingand time‐consuming.•Worker must stoop, lift, and grip repeatedly.
One Solution:Use mesh bags to speed the process.•Erect posture while removing and draining leaves.•Greater amount per trip: can use batch p g p p y
•Slow washing reduces crop quality.•There is static load on arms while holding produce to drain.•Hands are in direct, frequent contact with cold
•Greater amount per trip: can use batch processing.•Able to wash 50% more greens (by weight) in the same amount of time.•Faster process maintains crop qualityq
water.•Rough handling lowers crop quality.
•Faster process maintains crop quality.•Hands spend less time immersed in cold water.•Less chance of leaf damage from crushing.
One Solution:Problem:When plants are kept on the ground, workers must bend completely forward to
d h k l b k bl
Use a movable table to elevate trays while weeding.
weed them, risking low‐back problems.
lResults:Ideas were evaluated on potential cost, acceptability to workers, and impact on harvest speed. The ergonomic belt redistributes weigh from the upper back, neck and shoulders to the hips and does not appreciably slow picking speed. In laboratory studies, significant to the hips and does not appreciably slow picking speed. In laboratory studies, significant reductions in muscle activity were seen with belt use.
Simple Solutions Are Cost‐Effective!Effective!
University of Wisconsin Biological Systems Engineering Department made estimates of costs, profit improvements, and work hours affected.
Innovation Percent of Work Force Affected
Percent of Work Hours Affected
Possibility for Profit Improvement
Net bag wash 60% 10‐20% High $24 (six bags)gsystem
g 4 g
Standard containers 75‐95% 10‐20% Medium‐high $120 (12 containers)
Pallets andhand truck
80% 20‐50% High to very high $750 (75 pallets & truck)
COMBINED ERGO RISKCOMBINED ERGO RISK FACTORS: AWKWARD + HEAVYFACTORS: AWKWARD HEAVY
INJURY RATES DOUBLE WITH WORK IN A TWISTED POSITION FOR MORE THAN 25% OF THE WORK SHIFT OR WHEN EXPOSED TO HEAVY THE WORK SHIFT OR WHEN EXPOSED TO HEAVY LIFTING DAILY
INJURY RATES DOUBLE AGAIN WHEN HEAVY INJURY RATES DOUBLE AGAIN WHEN HEAVY LIFTING IS COMBINED WITH A TWISTED POSTURE
Ramazzini wrote of Ramazzini wrote of the relationship between deformities between deformities of dockworkers and t d k stooped work postures in 1713
R i i B D M bi A ifi Di ib (Di Ramazzini, B. 1713. De Morbis Artificum Diatriba (Diseases of Workers). Latin 1713 second edition ed. University of Chicago Press, Chicago
When lifting in trunk flexion, spinal loads may be 2‐3x that in neutral posture S h d d f i i i h lif i i Strength decreases and fatigue increases with lifting in flexion‐‐‐likely exceeding recovery and ability to remodel damaged tissue (Gallagher S et al 2002 remodel damaged tissue (Gallagher S et al, 2002 Ergonomics 45:380‐98.)
Repeated or prolonged stooping may also weaken the p p g p g yneuromuscular and ligamentous stability of the low back
Regulation of stooped and squatting posturessquatting postures
C lif i l d h f h h dl d l California 1975 outlawed the use of short handled tools in agriculture due to Low Back
Legislation did not prohibit activities done by hand 2004 legislation amended to prohibit hand weeding and 4 g p gthinning unless no viable alternative If by hand, an additional 5 minutes of rest per work period
Harvesting Maine Blueberries withHarvesting Maine Blueberries with Blueberry Rakes
Short‐ and long‐handled blueberry rakesMay E et al AJIM 55 2012May E et al AJIM 55, 2012
Problem:Harvesting blueberries with a traditional rake is hard on the bod rake is hard on the body. • Stooped position hurts the back.• Thin handle is hard to grip comfortably.• Rake design causes worker to flex wristsgand to use pinch grip with fingers, riskingtendinitis in wrists and hands.• Steel rake is heavy, up to four pounds.
After a pilot study employing 12 rake designs, the project focused on a comparison p y p y g g p j pbetween the extended handle modification and the traditional, short handle blueberry rakes. Saw increased productivity, greater acceptability, less force used and less pain reported with the extended handle design.
AVOID INAPPROPRIATEAVOID INAPPROPRIATE SUBSTITUTION
Kneeling and squatting postures are significant ib W SD f h k d l b k contributors to WMSD of the knees and low back
(Welch 2004 Stoop Conference)
High odds ratio for knee injury in jobs requiring squatting or kneeling for more than 1 hr/day (Baker P squatting or kneeling for more than 1 hr/day (Baker P et al 2003 Occup Environ Med 60:794‐7)
B fit f U i H t C tBenefits of Using a Harvest CartLess fatigue and discomfort. Prolonged kneeling to harvest, transplant, or weed puts small scale growers in one of the highest risk groups for occupational injuries. Harvesting from a seated g p p j gposition eliminates knee strain and is less tiring for the back, hamstrings, and torso. Kneeling requires at least 25% more energy and stooping requires at least 45% more energy than sitting does
This material was developed by the HealthyFarmers, Healthy Profits Project, whose goal is tofind and share work efficiency tips that maintainfarmers’ health and safety and also increase profits.For more information, visit our web site atsitting does. http://bse.wisc.edu/hfhp/ or call 608‐265‐9451.Healthy Farmers, Healthy Profits Project,Department of Biological Systems Engineering,College of Agricultural and Life Sciences,University of Wisconsin, 460 Henry Hall,Madison, WI 53706.Feel free to reproduce; please
BASIC ERGO: REDUCE EXCESSIVEBASIC ERGO: REDUCE EXCESSIVE MOTIONS
HIGH TASK REPETITIVE MOTIONS WHEN HIGH TASK REPETITIVE MOTIONS WHEN COMBINED WITH HIGH FORCE AND/OR AWKWARD POSTURES CAN INCREASE THE RISK OF WMSD CYCLE TIME IS 30 SECONDS OR LESS= HIGHLY REPETITIVEREPETITIVE
Manual clipping‐Power toolManual clipping Power tool
BASIC ERGO: MINIMIZEBASIC ERGO: MINIMIZE CONTACT STRESSCONTACT STRESS
CONTACT STRESS RESULTS FROM CONTINUOUS CONTACT STRESS RESULTS FROM CONTINUOUS CONTACT OR RUBBING BETWEEN HARD OR SHARP OBJECTS/SURFACES Sharp edges, pressing tool handles into palms, hammering, sitting without adequate space for knees
Poorly‐designed tool: Handle presses into base of palm and Poorly designed tool: Handle presses into base of palm and requires user to open after each cut (no spring).
Well‐designed tool: Handles are long. Spring return keeps tool open. Handles are covered with rubber or plastic grip.
REDUCE EXCESSIVE VIBRATION HAND ARM VIBRATION SYNDROME
RAYNAUD’S, CTS, TENDONITIS Best Solution is in initial design of machinery or subsequent dampening of vibration
(C ti ith l ) (Caution with gloves)
OTHER CONCERNS:TEMPERATUREOTHER CONCERNS:TEMPERATURE
HEAT RELATED ILLNESSES HEAT RELATED ILLNESSES ILLNESSES AND DEATH ARE PREVENTABLE
Heat exposure and dehydration are associated with diminished concentration, strength, and productivity
d d dand increased accident rates
STRESS Farmers have high incidence of stress related diseases‐‐‐CAD, hypertensioni i l [ h ] Financial concerns [weather]
NIOSH: SIMPLE SOLUTIONSNIOSH: SIMPLE SOLUTIONSBaron et al, 2001
Highlights most successful interventions Keys to success:
Cooperative partnership between farmers, farm workers through intervention development and trial
Focus on the commodity or crop specific tasks or tools Focus on the commodity or crop specific tasks or tools Intervention focused on health as well as ergonomic outcomes
Fitting interventions to accepted production methods to encourage adoption and minimize worker displacement
NIOSH Recommends Research + outreach specialists + pilot farmers and ag specialists + employer + funding + same focus:
IDENTIFICATION IDENTIFICATION CONTROL PREVENTION/INTERVENTION EVALUATION PREVENTION/INTERVENTION EVALUATION
OSHA 2014 ERGONOMICS CITATIONCITATION
Alabama's Wayne Farms poultry plant cited for i k l k l l i exposing workers to musculoskeletal, repeat, serious
safety and health hazardsOSHA proposes more than $102K in finesOSHA proposes more than $102K in fines
Citation 1 Item 1 Type ofCitation 1 Item 1 Type of Violation: Serious
OSH ACT of 1970 Section (5)(a)(1): The employer did not furnish employment and a place of employment which were free from recognized hazards that were causing or lik l t i h i l h t l i th t likely to cause serious physical harm to employees, in that employees were required to perform manual tasks involving ergonomic risk factors including, but not limited to limited to excessive force or exertion, repetitive motions, and
awkward postures, resulting in stressors that had caused, were causing, or were likely to causeg y
musculoskeletal disorders (MSDs) such as but not limited to tendonitis, carpal tunnel syndrome, trigger thumb and shoulder sprain.
RECOMMENDED ABATEMENTRECOMMENDED ABATEMENT ACTION
Analysis of the worksite Medical management Education of employees and supervisors and onsite medical staff in recognition and prevention of injuryH d i d l i i k Hazard prevention and control re ergonomic risk factors‐engineering and administrative
Review of injury and complaint logs Review of injury and complaint logs
FEASIBLE AND USEFUL METHODS OF CORRECTION
Work shift rotation to tasks using different efforts Work shift rotation to tasks using different efforts Increase cycle time for each task Provide sharp knives with handles designed for Provide sharp knives with handles designed for repetitive tasks
Install skin removal equipment or gloves to reduce q p ghand force
Powered scissors Platform height adjustments Fatigue mats Temperature breaks or localized heating for hands No overtime work in debone
ADDITIONAL METHODS OFADDITIONAL METHODS OF REDUCING THE ERGONOMIC
HAZARDSHAZARDS Provide ergonomic assessment by CPEE h di l t i d it Enhance medical management screening and onsite assessment Recommendations for alternate duty for those reporting Recommendations for alternate duty for those reporting pain
Develop a participatory, multi‐disciplinary competent ergo team Worker, management, safety, medical and engineering
The ergonomic standard lives?
Time for coming attractions?
ADDITIONAL REFERENCESADDITIONAL REFERENCES National Ag Safety Database Nasdonline org/document/1927/d001873/stooped andNasdonline.org/document/1927/d001873/stooped‐ and‐squatting‐postures‐in‐the‐workplace.html Conference: Stooped and Squatting Postures in the Workplace; Oakland, CA 2004Oakland, CA 2004
NIOSH Simple Solutions, Baron S et al 2001, cdc.gov/niosh/docs/2001‐2011.pdf
MAY E et al “An Ergonomic Assessment of the Long MAY, E et al An Ergonomic Assessment of the Long Handle Blueberry Harvesting Rake” AJIM 55:1051‐1059 (2012)
RI 9684 REPORT OF INVESTIGATIONS/2011: RI 9684 REPORT OF INVESTIGATIONS/2011: PRACTICAL DEMONSTRATION OF ERGONOMIC PRINCIPLES @ CDC.GOV
8 FUNDAMENTAL ERGONOMIC PRINCIPLES FOR 8 FUNDAMENTAL ERGONOMIC PRINCIPLES FOR BETTER WORK PERFORMANCE @ERGO‐PLUS.COM AUTHORED BY MARK MIDDLESWORTH
ADDITIONAL REFERENCESADDITIONAL REFERENCES Ergonomics and Musculoskeletal Injuries in Agriculture: Recognizing and Preventing the Industry’s Most Widespread Health and Safety Industry s Most Widespread Health and Safety Problem; Chapman L and Meyers J: UC‐Berkeley and University of Wisconsin‐Madison Extension ynasdonline.org/document/1839/d001771/ergonomics
Strawberry fields photo: fruitguys.com How Broccoli Will Save Strawberries Organic Farming Practices Leave Pesticides Aside, Heidi Lewis
COMING ATTRACTIONS:COMING ATTRACTIONS:
SHIP GRANT FROM L&I
>PARTICIPATORY ERGONOMICS: EARLY
SHIP GRANT FROM L&I
IDENTIFICATION AND RISK REDUCTIONREDUCTION
SHIP Project OverviewSHIP Project Overview---SURVEYINTERVENTIONSURVEY
1 Survey of 16 tasks to identify discomfort in custodians at UW1. Survey of 16 tasks to identify discomfort in custodians at UW (AUG‐SEPT)
2. Small group work for 4 tasks (OCT‐NOV)1. Which four tasks were chosen?2. How will we try to improve the tasks to cause less discomfort?
3. All custodians in Building Services are invited to start doing changed tasks (DEC‐JAN)changed tasks (DEC JAN)
4. Final Survey (APRIL)
Survey OverviewSurvey Overview
133/222 custodians took the survey
76 females47 l
133/222 custodians took the survey
47 males Most common age range = 50‐59 years Average time at UW = 13 3 yearsAverage time at UW = 13.3 years Range of years at UW = less than one year to 34 years % who feel most relaxed listening to English = 58%g g % who feel most relaxed listening to another language = 35% 113 right‐handed, 7 left‐handed, 6 both
Survey ResultsTasks that cause high discomfort for many people:1. Vacuum Backpack2 Cl T il2. Clean Toilets3. Scrape Floor4 Picking up and dumping garbage4. Picking up and dumping garbage
REFERENCES Fruit_harvesting_ENG 122009_LR.pdf
Problem:Manual application of liquids (such as growth regulators) with a spray‐wand can cause worker
One Solution:Use a semi‐automated, metered liquid applicatorto provide a precise dose to each
injury, as well as waste of chemicals and plant loss.•Worker must squeeze and hold spray‐wand trigger up to 25 times per minute.
plant and to eliminate repetitive handclosure.•Eliminates virtually all of the repetitive hand‐squeezing motion.
•Highly repetitive hand closure can cause inflammation of the tendons in the carpal tunnel.•Mental counts to “time” the discharge can result
•Can reduce waste of chemicals and plant loss.•Curved wand design improves wrist posture for long reaches.•Can improve productivity.
in inconsistent or improper amounts.•Many spray‐wands currently in use are not appropriate for long reaches, resulting in prolonged poor wrist posture.
•Can document production, if fitted with a counter.
Problem:Long‐handled metal floor scraper (used for cleaning up dirt and mud) requires lots of force to grip and to push
One Solution:Attach an eight‐inch bar handle to top of scraper.•Gives a better griplots of force to grip and to push.
•Nothing to grip.•Cannot comfortably be pushed with the
•Gives a better grip.•Disperses contact force over a larger area.
Figure 1. Neutral and awkward wrist postures.
Figure 2. Neutral and awkward elbow postures postures.
PROPOSED MECHANISM OF LOW BACK INJURIESLOW BACK INJURIES
Accumulation of microfractures by excess loading or repetive submax loading of the endplate scar tissueinhibition of nutrition to the discfissures in tissueinhibition of nutrition to the discfissures in the annulus fibrosisdisc material migrationinflammationpaindecreasedg ptolerance and work capacity
CATEGORY PRIORITY RESEARCH AREASDISEASE & INJURYJMusculoskeletal DisordersRespiratory DiseaseSkin DiseaseTraumatic InjuriesTraumatic Injuries
WORK ENVIRONMENT & WORKFORCE Chemical ExposuresSpecial Populations at RiskSocial and Economic Foundations of Workplace SafetyRisk Communication Barriers
RESEARCH TOOLS & APPROACHES
Diagnostic ApproachesH d C l T h lHazard Control TechnologyIntervention EffectivenessSurveillance Research Methods
Problem:Lifting and carrying plant containers by hand can cause injuries.
One Solution:Use specially designed handles to pick up y jand carry containers.
How Does the Lifting Tool Work?The tool has three parts: a) the hand‐grip, b) the container coupling, and c) the 16‐inch t i It i d f l i d t l d h t k b t ith ll extension. It is made of aluminum and steel and has proven to work best with 5‐gallon
containers that have an external lip. From a standing position the worker slides the coupling point under the container’s lip and lifts.
DIBBLE DRUM FOR PLANTINGSaves time. You can set out, plant, and water transplants 24% faster when using a dibble drum p 4 gto space and dig holes, compared to visually estimating spacing and using a trowel.
Easier on the body.Using a dibble drum to space transplants lets you stand instead of stooping or kneeling to mark transplant spacing.p p g
Hierarchy of Controls Engineering Administrative PPE
Lifting from a good height, between waist and shoulder level.g g g