HEALTH ERGONOMICS - taskSPECIAL TOPICS

I Putu Gede ADIATMIKA/ I Made MULIARTA

Center for Ergonomics Study (CES) Udayana University

History - OrganizationFirst World war 1949 ErgonomicsInternational International Ergonomics Association (IEA)Asia Asian ErgonomicsSoutheast Asia SEANESIndonesia IES / PEI

Scenario :A man, 50 years old, come to the general practitioner clinic with the complaint of pain on shoulder and neck since two weeks ago. The complaint was intermittent and getting worse when he work at the office. He work as an operator of computer and must sit in front of computer for most of his time. His working time at 08.00-16.00 pm and 12.00-13.00 resting time. On physical examination was found that blood pressure was normal, tenderness on the shoulder, without any signs of inflammation. The patient said that his table and computer monitor was too high for him.

Learning task :Identify the problem of the patient ?Explore the factors that cause pain on the shoulder and neck ?What is the your opinion about the working condition of this patient ?Explain about biomechanical, physiological and anthropometric aspect that affect to this patient's complaint ?Why we should consider the anatomical position as a reference of working posture ?Explain the role of human body when do some task such lifting, carrying, pulling, pushing ? How is the human body adaptation for that tasks.

INTRODUCTIONAdvance technology and science human lifeEscalating incidents of stress related and musculoskeletal disorders (MSDs)Affect to productivity

Working conditionDesigning of working condition should consider to employees capacityErgonomic intervention is one of the manner to provide optimum working conditionBad of working condition will cause some problemsIncreasing of risk of injuryMusculoskeletal disorders (MSDs) on neck, back, lower back etc.

Lower backCases : of adults have low back pain15 % frequent back pain in last 2 weeks1 million people need treatment and recover of MSDsCompensation $ 45 54 billion / year

Human at workActivity is a must in human life adaptationWork is one of human activities

Some tasks must be done as consequencies to complete the work or job

PROBLEM : NOT ALL TASKS ARE FIT TO THE HUMAN

Activities

Fitting the task to the humanThere are many tasks must be done during human lifeHuman have different capabilitiesLimitationAbilityWeakness

Human must fit with the task or fit the task to the human (Grandjean, 2000)

How human adapt to the task?Physiologically, task is a stimulusHuman must react to make an adaptation

Human body will make specific posture and movement according to the taskType of posture and movement are depend on the task

Human body activity for the task?Some activities were conducted to complete the taskLiftingCarryingPushingPulling

Pulling

Lifting and pushing

Type of posture and movementPOSTURESittingStandingWalkingCombination

MOVEMENTBendingTwisting Awkward Backward

Bending and twisting

Awkward

What should pay attention while do the task ?Should understand to posture and gesture

Can be explained by :Anthropometric aspectsPhysiological aspectsBiomechanical aspects

Affect to Health such as:Energy expenditureMusculoskeletal disordersWork injuryWork related diseases, etc

Biomechanical aspectsRefer to human body in normal position / anatomical positionNormal posture and gestureAs a references when improve a bad posture and gesture in a working condition

Balance of force between the task and force within the bodyPosture and gesture will give stress to the bodyAdaptation effort will be done by the bodyMusculoskeletal as a lever system

Anthropometric aspects Any tools and other product were design for the humanMust fit to the humanEasy to be operated by the workers

Working condition is for the human being Must be design for the human as the userFit to the human need in activity or work

Design work station based on anthropometric dataAsses the human body dimensions

ANTHROPOMETRICSHUMAN DIMENSIONS OR BODY SIZE:HEIGHT, LENGTH, WEIGH, REACHING,

Use the anthropometric tables appropriate for specific populations

Physiological aspectsMusculoskeletal systemAdaptation need the activity of musculoskeletal systemMuscle and bone must have a proper time for contraction and relaxationProne to injury and diseases

Energy expenditureAny activities need energy to supply to whole system activitiesNutrition, oxygen delivery system must optimu

Physiological aspectsWork load will affect to the human body stressInternal (genetics, BW, Ht, Wt, etc)External (physic and psychology)Increasing activity of heart, lung, kidney, nerves system, etc

Biomechanical, physiological and anthropometric backgroundJoint must in neutral positionKeep the work close to the bodyAvoid bending forwardA twisted trunk strains the backSudden movement and forces produces peak stressesAlternate posture as well as movement

Limit the duration of any continuous muscular effortPrevent muscular exhaustionMore frequent short breaks are better than a single long oneLimit the energy expenditure in a taskRest is necessary after heavy taskTake account of difference in body size

Effect to human bodyWork related musculoskeletal disordersRepetitive strain injuryLower back painWork accidentTraumaTraffic accidentWork diseasesLung diseaseCanceretc

Workstation, posture and gesture (

Workstation

Workstation

Suggestion

POSTURESelect a basic posture that fits the job

Sitting

SITTING POSITION

SQUATING POSTURE

Sitting Alternate sitting with standing and walkingThe height of the seat and back rest of chair must be adjustableLimit the number of adjustment possibilitiesProvide proper seating instructions

Specific chair characteristic are determined by the taskThe work height depends on the taskThe height of the work surface, seat and feet must bee compatibleUse a footrest if the work height is fixedAvoid excessive reaches

Select a sloping work surface for reading taskAllow sufficient legroom

STANDING POSTURE

Work station for standing position

Standing Alternate standing with sitting and walkingThe work height depends on the taskHeight of the work table must be adjustableDo not use platformsProvide sufficient room for the legs and feet

Avoid excessive reachesSelect a sloping work surface for reading tasksOffer variation in task and activitiesIntroduce sit-stand work stationsAlternate sitting posturesMake occasional use of a pedestal stool in standing work

Reach due to human and work

Upper reaching

Front reach

Hand and arm positionSelect the right model of toolDo not bend the wrist, use curved tools insteadHand-held tools must not be too heavyMaintain your toolsPay attention to the shape of handgrips

Avoid carrying out tasks above shoulder levelAvoid working with the hands behind the body

MOVEMENT

Lifting Restrict the number of tasks which require displacing loads manuallyCreate optimum circumstances for liftingEnsure that people always lift less and probably much less, than 23 kgIndividual loads should not be too lightMake the workplace suitable for lifting activities

Loads should be fitted with handgripsEnsure that the load is of the correct shapeUse the correct lifting techniqueHeavy lifting should be done by several peopleUse lifting accessories

Lifting method

Lifting and bending posture

Carrying method

Carrying load

Carrying Limit the weight of the loadHold the load as close to the body as possibleProvide well-designed handgripsAvoid carrying loads with one hand Use transport accessories

Pulling and pushing method

Pulling and pushingLimit the pulling and pushing forceUse the body weight when pulling or pushingProvide handgrips on trolleysA trolley should have two swivel wheelsEnsure that floors are hard and even

NoHAZARDIDENTIFICATION OF HAZARDYESNO1Repetitive motions especially during prolonged activities ( Gerakan berulang, terutama selama aktivitas berkepanjangan)2Sustained static or awkward postures ( sikap statis atau ALA KUCING tidur terus menerus)3Excessive bending or twisting of the wrists (bungkuk atau memutar dp pinggang yg berkelebihan)4Continued elbow or shoulder elevation (overhead work) (deviasi siku atau bahu terus menerus)5Forceful exertions or heavy lifting especially in an awkward posture (regangan yg kuat atau angkat berat dgn sikap tidak alamiah/ membungkuk)6Excessive use of small muscle groups especially pinch grip (Penggunaan berlebihan dp kelompok otot kecil terutama pd saat menjepit benda)7Acceleration and velocity of dynamic motions in high speed assembly ( Percepatan dan kecepatan gerakan dinamis di assembly dgn kecepatan tinggi)8Mechanical compression (sharp edge on a desk, seat or hand tool (kompresi mekanis dari pinggiran tajam pd meja, kursi atau alat tangan)9Vibration (getaran)10Restrictive workstation (inadequate clearance) tempat kerja yg terbatas (clearance tidak cukup)11Improper seating or support (tempat duduk tidak memadai/cukup atau kurang mendukung)12Inappropriate hand tools ( tidak memadainya alat tangan)13Machine pacing and production based incentives ( insentive berdasarkan kecepatan mesin dan produksi)14Extreme temperatures ( temperature yg ekstreem)15Extended exposure to hazardous or annoying Noises (pemaparan yg lama thd bising yg berhazard atau mengganggu16Improper lighting (Penerangan yg tidak memadai)17Work organization and occupational and psychosocial factors (organisasi kerja dan stress kerja / faktor okupasi dan psikososial)

What is the role of the doctor????Medicine? Ergonomics?

CHECK LIST

BIOMECHANICAL BACKGROUNDAre the joints in neutral position?Is the work held close to the body?Are forward-bending postures avoided?Are twisted trunk postures avoided?Are sudden movements and forces avoided?Is there a variation in postures and movements?Is the duration of any continuous muscular effort limited?Is the muscle exhaustion avoided?Are breaks sufficiently short to allow them to be spread over the duration of the task?

PHYSIOLOGICAL BACKGROUNDIs the energy consumption for each task limited?Is rest taken after heavy work?

ANTHROPOMETRIC BACKGROUNDHas account been taken of differences in body size?Have the right anthropometric tables been used for specific populations?

POSTUREHas a basic posture been selected that fits the job?

SITTINGIs sitting alternated with standing and walking?Are the height of the seat and back rest of the chair adjustable?Is the number of adjustment possibilities limited?Have good seating instructions been provided?Are the specific chair characteristics dependent on the task?Is the work height dependent on the task?Do the heights of the work surface, seat and feet correspond?Is the footrest used where the work height is fixed?Are excessive reaches avoided?Is there a sloping work surface for reading tasks?Is there enough legroom?

STANDINGIs standing alternated with sitting and walking?Is work height dependent on the task?Is the height of the work table adjustable?Has the use of platforms been avoided?Is there enough room for the legs and feet?Are excessive reaches avoided?Is there a sloping work surface for reading task?

CHANGE OF POSTUREHas an effort been made to provide a varied task package?Have combined sit-stand workplaces been introduced?Are sitting postures alternated?Is a pedestal stool used once in a while in standing work?

HAND AND ARM POSTURESHas the right model of tool been chosen?Is the tool curved instead of the wrist being bent?Are hand-held tools not too heavy?Are tools well maintained?Has attention been paid to the shape of handgrips?Has work above shoulder level been avoided?Has work with the hands behind the body been avoided?

LIFTINGHave tasks involving manual displacement of loads been limited?Have optimum lifting conditions been achieved?Has care been taken that any one person always lift less, and preferably much less, than 23 kg?Have lifting situations been assessed using the NIOSH method?Are the weights to be lifted not too light?

LIFTINGAre the workplaces suited to lifting activities?Are handgrips fitted to the loads to be lifted?Does the load have a favorable shape?Have good lifting techniques been used?In more than one person involved in heavy lifting?Are lifting accessories used?

CARRYINGIs the weight of the load limited?Is the load held as close to the body as possible?Are good handgrips fitted?Is the vertical dimension of the load limited?Is carrying with one hand avoided?Are transport accessories being used?

PULLING AND PUSHINGAre pulling and pushing forces limited?Is the body weight used during pulling and pushing?Are the trolleys fitted with handgrips?Do the trolley have two swivel wheels?Are the floors hardened and even?

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