Applied Ergonomics - PDF document

1 Applied Ergonomics 19%. U(2): 91-99
Applied Ergonomics 19%. U(2): 91-99 RULA: a survey method for the. of world-related upper limb disorders Lynn McAtamney and E Nigel CorlettInstitute for Occupational Ergonomics, University of Nottingham, University Park, NottinghamNG7 2RD, UKRULA (rapid upper limb assessment) is a survey method developed for use inergonomics investigations of workplaces where work-related upper limb disorders arereported. This tool requires no special equipment in providing a quick assessment ofthe postures of the neck, trunk and upper limbs along with muscle function and theexternal loads experienced by the body. A coding system is used to generate an actionlist which indicates the level of intervention required to reduce the risks of injury dueto physical loading on the operator.It is of particular assistance in fulfilling theassessment requirements of both the European Community Directive (90/270/EEC) Working posture, assessment, upper limb disorders, RSI d This paper describes the development of a posture,force and muscle use assessment tool. Called RULA work- related upper limb disorders. Part of the developmenttook place in the garment-making industry, whereassessment was made of operators who performed tasksincluding cutting while standing at a cutting block,machining using one of a variety of sewing machines,clipping, inspection operations, and packing. RULAwas also developed through the evaluation of thepostures adopted, forces required and muscle actions ofboth VDU operators and operators working in avarietv of manufacturing tasks where risk factorsassociated with upper limb disorders may be present.The method uses diagrams of body postures andthree scoring tables to provide evaluation of exposureto risk factors. The risk factors under investigation arethose described by McPhee’ as external load factors.These included:l numbers of movements; static muscle work; 0 force;l work postures determined by the equipments andfurniture;l time worked without a break.In addition to these factors McPhee cited otherimportant factors which influence the load, but whichmay vary between individuals. These were the workpostures adopted,unnecessary use of static musclework or force, speed and accuracy of movements, thefrequency and the duration of pauses taken by theoperator. Third, according to McPhee, are factors whichaltered the individual’s response to a particular load,individual factors (such as age and experience), work-place environmental factors and psychosocial variables,Many other authors have also reported on risk factorsassociated with upper limb disorders*? In an effort to assess the first four external loadfactors described above (number of movements, staticmuscle work, force and postures], R’LJLA was developedto: provide a method of screening a working popu!ation quickly, for exposure to a likely risk of work-relatedupper limb disorders;2 identify the muscular effort which is associated withworking posture,exerting force and performingstatic or repetitive work, and which may contributeto muscle fatigue; Vol 24 No 2 April 1993 0003/6870/93/02 0091-09 $07.50 @ 1993 Butterworth-Heinemann Ltd 91 RULA: a survey method for the investigation of work-related upper Limb disordersnumbered so that the number 1 is given to the range ofmovement or working posture where the risk factorspresent are minimal. Higher numbers are allocated toparts of the movement range with more extremepostures indicating an increasing presence of riskfactors causing load on the structures of the body segment. This system of scoring each body part postureprovides a sequence of numbers which is logical andeasilv remembered.Group A Figure 1 shows the diagrams for scoring theposture of the body parts in Group A, which are theupper arm, lower arm and wrist, with a section torecord the pronation or supination occurring (called‘wrist twist’).3 give results which could be incorporated in a widerergonomicsassessment covering epidemiological, phvsical, m~:ntal, environmental and organizatioralfacto

2 rs, and particularly to assist in fulfil
rs, and particularly to assist in fulfilling theassessment requirements of the UK Guidelines on theprevention of work-related upper limb disorders.RULA was developed without the need for speciJ equipment. This provided the opportunity for a numberof investigators to be trained in doing the assessmentswithout additional equipment expenditure. As theinvestigator only requires a clipboard and pen, RULAassessments can be done in confined workplaces withoutdisruption to the workforce. Those who are trained touse it do not need previous skills in observationtechniques although this would be an advantage.When reviewing the literature, various methods arefound to assess the postures, movements and forcesexerted while performing a job and their effect on thephysical capacity and capability of the person. Surveymethods have been developed to gather informationabout the musculoskeletal complaints reported byTo allow easy identification of the posture rangesfrom the diagrams, each body segment is presented inthe sagittal plane. If a posture cannot be represented inthis way, for example when abduction occurs, thescoring to be adopted is described beside the diagram.the working population’. Kemmlert and Kilbom” developed a checklist of questions which links riskfactors at work with information about operator’sreports of body part discomfort. Methods to evaluatethe working P osture are also reported upon, either byobservation’ .l*, videotape, optical or frame-grabbingThe use of task analysis to evaluate theforces exerted, frequency of movements and workingpostures adopted is reported by Drury’“. However, although all these methods are undoubtedlyuseful, they were developed for different purposesfrom RUL,4. The rangesof movement for the upper armwereassessed andscored on the basis of findingsfromstudies carried out by Tichauer? Chaffin”, Herberts et a118, Hagberg”, Schuldt et ape, and Harms-Ringdahl and Schuldt”’ . The scores are: * 1 for 20” extension to 20” of flexion; l 2 for extension greater than 20” or 2w5” of flexion; 3 for 45-90” of flexion; 4 for 90” or more of flexion. The development of RULAThe development of RULA occurred in threephases. The first was the development of the methodfor recording the working posture, the second was thedevelopment of the scoring system, and the third wasthe development of the scale of action levels whichprovide a guide to the level of risk and need for actionto conduct more detailed assessments.If the shoulder is elevated the posture score derived asabove is increased by 1. If the upper arm is abductedthe score is increased by 1. If the opeator is leaning orthe weight of the arm is supported then the posturescore is decreased by 1.The ranges for the lower arm are developed fromwork by Grandjean** and Tichauer? The scores are:l 1 for 60-100” flexion; l 2 for less than 60” or more than 100” flexion. If the lower arm is working across the midline of thebodv or out to the side then the posture score is increased by 1.STAGE I: The development of the method forrecording working posturesTo produce a method which was quick to use, thebody was divided into segments which formed two groups: A and B. Group A includes the upper andlower arm and wrist while Group B includes the neck,trunk and legs.This ensures that the whole bodyposture is recorded so that any awkward or constrainedpostures of the legs,trunk or neck which mightinfluence the postures of the upper limb are included inthe assessment. The OWAS system’*, which uses theconcept of numbersto represent postures with anassociated coding system, is a clear and concise methodwhich can be used quickly. This was used as a suitablebasis for RULA.The guidelines for the wrist issued by the Health andSafety Executive23 are used to produce the followingposture scores: 0 1 if in a neutral position;l 2 for O-15” in either flexion or extension; o 3 for 15” or more in either flexion or

3 extension.If theWrist is ineither radia
extension.If theWrist is ineither radial or ulnar deviation then the postu score isincreasedbv 1.Pronation and supination of the wrist (wrist twist) aredefined around the neutral posture b; :jed on Tichauer’“.The scores are:l 1 if the wrist is in mid-range of twist;l 2 if the wrist is at or near the end of range of twist.The range of movement for each body part is dividedGroup B The posture ranges for the neck are based oninto sections according to criteria derived throughstudies by Chaffin” and Kilbom et a/“? The scoresinterpretation of relevant literature. These sections areand ranges are: L MCATAMNEY AND E N CORLE-I-I- Add I ra lsed shoulder isAdd I if upperabductedarm 1s Subtract I rf lecning or supporting thi weight of the armLower ufms tw/st Add I ifworking acrossthe midline ofthe body or outto the sideAdd Iif wrist is bentawayfrom the midline 1 Mainly In mid- range of twist At or near the end of twisting rangeFigure 1 The posture scores for body part group A, the upper arm, lower arm. wrist and wrist twist 0 1 flexion; 2 for N-20” flexion; 3 for 20” or more flexion; 4 if in extension.If the neck is twisted these posture scores are increasedby 1. If the neck is in side-bending then the score isincreased by 1 (Figure 2).The ranges for the trunk are developed from Drury15, and Grandjean et al’“. 0 2 for O-20” flexion; 3 for 20-60” flexion; 0 4 for 60” or more flexion. If the trunk is twisting the score is increased by 1. If thetrunk is in side-bending, the score is increased by 1. The leg posture scores are defined as:l 1 if the legs and feet are well supported when seatedwith weight evenly balanced;l 1 if standing with the body weight evenly distributedover both feet, with room for changes of position;l 2 if the legs and feet are not supported or the weightis unevenly balanced.. . . w., Recording the posture score The assessment commencesby observing the operator during several work cycles inorder to select the tasks and postures for assessment.Selection may be made of the posture held for thegreatest amount of the work cycle or where highestloads occur. As RULA can be conducted quickly, anassessment can be made of each posture in the workcycle. When using RULA, only the right or left side isassessed at a tirne. After observing the operator it maybe obvious that only one arm is under load; however, ifundecided, the observer would assess both sides.Using Figure 1 the observer records the posturescores for the upper arm,lower arm, wrist and wristtwist in the column of boxes marked A on the left sideof the score sheet (Figure 3). Similarly, using Figure 2,the posture scores for the neck, trunk and legs arecalculated and recorded in the column of boxes marked X3 on the score sheet.. , t The level of detail required in RULE was selectedto provide enough information upon which initialrecommendations can be made, but also to be briefenough to be administered quickly as an initial screen-ing tool. The balance of detail was discussed anddeveloped over some time with the assistance of fourergonomists and an occupational physiotherapist. ! a survey method for the investigation of work-related upper limb disorders Neck Add I if the neckis twistingAdd I if neck isside- bendingAdd I if trunkis twistingAdd I if trunk isside - bending O-IO0 I also iftrunk is weI1 I n ext’n Legs if legs and feet ore well supported and in an evenly balanced postureFigure 2 The posture scores for body part group B, the neck, trunk and Iegs if notTask Lower orm E \ twat Use Tub/e APosture score A Tub/e 6 Posture score B fl Use Tub/e CMuscle postures. The first step in establishing such a systemwas to rank each posture combination from the least tothe greatest loading based on biomechanical andmuscle function criteria2’. This process was conductedover some time by two ergonomists and an occupationalphysiotherapist. Each ranked the postures on a scalefrom I to 9. A score of 1 was defined as the

4 posturewhere the least musculoskeletal l
posturewhere the least musculoskeletal loading occurred.Where differences in the scores occurred the loads onthe musculoskeletal system were discussed and a scoreagreed. This produced a table of consolidated bodysegment posture scores called posture score A and Brespectively.The next step was to observe video recordings of tensubjects who performed one of five tasks. The taskswere data processing operations, sewing machineoperations, production line packing, brick sorting and awire-twisting task. The posture scores A and B werecalculated and ordered from the lowest to the highest.Then the videotaped postures were reviewed in orderof their scoring so that the level of musculoskeleta! loading was compared for each posture score to revealany inconsistent scoring.The inconsistencies foundwere discussed and several adjustments to the scoreswere subsequently made. From’this process tables weredeveloped for groups A and B which were titled TableA (see Table 1) and Table B (see Table 2) and arepresented below. When the posture scores for eachFigure 3 The RUL14 scoring sheetTo provide a quickly administered screening tool,some detail is excluded from the RULA method and _can be considered in further developments. Most &- noticeably, the postural assessment of the fingers and 4 thumb may be required in some investigations where ‘( exposure to risk factors is high for these digits. RULAdoes not include such detail, although any force exertedby the fingers or thumb is recorded as part of theassessment prwedure: STAGE 2: Developmerlt of the system for grouping thebody part posture scores !3 (Figure 3): they are used in Tables f -“Body’ part are recorded in thef:olumns of boxes A’andusually done after the survey is completed.A single score is required from the Groups A and Bwhich will represent the level of postural loading of themusculoskeletal system due to the combined body partMuscle use and force scores A scoring svstem wasdeveloped to include the additional loah on the Table 1 Table A into which the individual posturescores for the upper limbs are entered to find posturescore AUpper Lower Wrist posture score armarm 3 W. twist W. twist W. twist W. twistI 1 32 33 3 4 4 4 4 4 5 5 5 4 4 4 4 4 5 5 5 4 4 4 5 5 5 6 6 5 5 5 5 5 6 6 7 5 6 6 6 6 7 7 7 6 6 6 7 7 7 7 8 7 7 7 7 7 8 8 9 8 8 8 8 8 9 9 9 9 9 9 9 9 9 9 91 2 2 2 2 3 3 3 2 2 2 3 3 3 32 3 3 3 3 3 4 42 3 3 3 3 4 4 43 3 3 3 3 4 4 43 4 4 4 4 4 5 5 3 3 4 4 4 4 5 53 4 4 4 4 4 5 4 4 4 4 4 5 5 5musculoskeletal system caused by excessive staticmuscle work, repetitive motions and the requirementto exert force or maintain an external load whileworking. These scores are calculated for each of thegroups A and B and recorded in the appropriate boxeson the score sheet. After the scores A and B have beencalculated from Tables 1 and 2, the muscle use andforce scores and added to them as shown below (seeFigures 4 and 5):Score A + muscle use and force scores for group A= Score CScore B + muscle use and force scores for group B= Score DAssessment of the amount of static loading or forcesexerted which will cause fatigue and subsequent tissuedamage is dependent upon the time that the operatorsare exposed to the external risk factors. RULA provides a simplifieh and conservative rating system tobe used as a guide to indicate whether these risk factorsare present. It would be the function of a subsequentmore detailed assessment to establish their extent andeffect on the operator’s wellbeing and work.In recent years studies have shown that very lowlevels of static loading are associated with musclefatigue. Bjorksten and Jonssor? have shown that staticmuscle work maintained for over 1 h should not exceed 5-6% of maximal voluntary contraction (MVC). Jonsson29 further suggested that static loading is accept-able only if it is lower than 2% of MVC whenmaintained for the entire working day. Grandjean** quantifies static loading in three categories relating tothe forces required. If a high force is exerted staticmuscle actions shoul

5 d be for less than 10 s; for amoderate f
d be for less than 10 s; for amoderate force, less than 1 min, and for a low force,less than 4 min.This was generalized in the RULA method so thatthe posture score (A or B) is increased by 1 if theposture is mainly static,that is, held for longer than1 min.The muscle use is defined as repetitive if the action isrepeated more than four times a minute. This isacknowledged as a conservative general definition fromwhich a risk may be present; however, further assess- Drury” provides a detailedassessment of repetition rate which is calculated withrespect to the postures adopted.The contributions of forceful actions or holdingloads, such as a hand tool, are dependent upon theweight of the object, length of holding and recoverytime as well as the adopted working posture. If the loador force is 2 kg or less and held intermittently then thescore is 0. However, if the intermittent load is 2-10 kg ascore of 1 is given.If the load of 2-10 kg is static orTable 2 Table B into which the individual posture scores for the neck, trunk and legs are entered to find posture score B Trunk posture score 1 3 6 LegsLegsLegsLegsLegs 5 23234555677733334455667774 5667777788 77778888888688888889 999 Vol 24 No 2 April 1993 95 RULA: a surve)* method for the investigation of work-related upper limb disorders a score of i if the posture ISl mclnl y static, eg held for longer thar? I mm l repeated more than C times ,/mtr! 3 The muscle use scores which are added to posture 0 I23 r;c -PSI stance l 2- IO kg IOkg l iOkg or more static load less thar static load2 ka cr force i l IOkg or more repeated I n?t?rm I t!er! loads or forces Iced o: farceIrepeated load or force l Sho:k or fgrces with CI ropd !x~Id-UP Figure 5 The force or load score which is added to posturescore A and Brepeated the score is 2. The score is also 2 if the load is Baidva”. The muscle use and force scores are assessed for thebodv part groups A and B and recorded in the boxesprovided on the score sheet of Figure 3. These are thenadded to the posture scores which are derived fromTables 1 and 2 respectively to give two scores calledscore C and score D.STAGE 3: Development of the grand score aud action . . t The third stage of RULA, and thus of its develop-ment, is to incorporate both score C and score D into asingle grand score whose magnitude provides a guide tothe priority for subsequent investigations. Each possiblecombination of score C and score D was given a rating.called a grand score, of l-7 based upon the estimatedrisk of injury due to musculoskeletal loading (‘Figure 6).For a grand+score of 1 or 2, the working posture wouldhave scored 2 or less for both body segments groups Aand B, and the scores for muscle use and force wouldbe 0. Working postures and actions which have a grandscore of 1 or 2 are considered acceptable if notmaintained or repeated for long periods. A grand scoreof 3 or 4 will be given to working postures which areoutside suitable ranges of motion as defined in the literature and also working postures which are withinsuitable ranges of motion but where repetitive actions,static loading or the exertion of force are required.Further investigation is needed for these operationsand changes may be required. A grand score of or 6indicates those working postures which are not withinsuitable ranges of motion: the operator is required toperform repetitivemovements and/or static musclework. and there may be a need to exert force. It issuggested that these operations are investigated soonand changes made in the short term while long-termmeasures to reduce the levels of exposure to risk factorsare planned. A grand score of 7 would be given to anv working postures at or near the end of range ofmovement where repetitive or static actions are required.Anv postures where the forces or loads mav be exc&sive are also included in this group. Invest&ion and modification of these operations is requiredimmediately to reduce excessive loading of the muscuio- skelet

6 al system and the risk of injury to the
al system and the risk of injury to the operator.The requirements for action into which the grandscores are divided is summarized into leve1J. asA ctiorl level I A score of 1 or 2 indicates that posture is acceptableif it is not maintained or repeated for long periods.Action level 2A score of 3 or 4 indicates that further investigation isneeded and changes may be required.Action level 3A score of 5 or 6 indicates that investigation andchanges are required soon.Action level 4A score of 7 indicates that investigation and changesare required immediately.The higher action levels will not, however, lead tounequivocal actions to eliminate any risks to theoperator. It must be strongly emphasized that, since thehuman body is a complex and adaptive svstem, simplemethods cannot deal in simple wavs with postural andloading effects on the body. What the RULA svstem provides is a guide, and was developed to drab boundaries around the more extreme situations. How-ever. the conbination of factors which influence theload but varv between operators, and factors whichalter the indLidua1.s response to a particular load’,may contribute to increasing the load from being withinacceptable boundaries to being a serious problem forsome people.For these reasons the action list leads. in most cases,to proposals for a more detailed investigation. To drawScore 0 (neck,trunk,leg) 3 68 I 2 5 6 7+1 Figure 6 Table C into which score C‘ score A plusthe muscle use score and the force or load score) and score D (posture score B plus the muscle use score and orload score) are entered to find the grand score the limits too tightly would lead to an undue expense inchanging jobs without any guarantee that those stillwithin the boundary would be safe. Hence the use ofRULA will give a priority order for jobs which shouldbe investigated, while the magnitude of the individualposture scores and the muscle use or exerted forcescores indicate which aspects of the postures are likelyto be those where trouble will be expected.It noted that while RULA provides a guideto the risks associated-with work-related musculoskeleta!injuries there is no substitute for some understanding ofoccupational ergonomics if sound decisions are to bemade on the basis of the information, when redesigningoperations.Assessment of the validity and reliability of RULA To assess the validity of RULA an experiment wasconducted in an ergonomics laboratorv using a VDTU- baseddata-entryoperation. Underlabo;atoryconditions the exposure of operators to postural loading could becontrolled. The aim of the experiment was to establishwhether RULA assessments provided a good indicationof musculoskeletal loading which might be reported aspain, ache or discomfort in the relevant body region.Sixteen experienced operators (1 male and 15 female,mean age 32.4 years) performed a VDU-based data- entry task of 40 min in one of two working postures.Each operator completed eight tasks (four in eachposture condition) during four sessions which wereconducted at the same time of day during fourconsecutive weeks.The order of postures wasrandomized.A height-adjustable chair and monitor stand wereused vvith a VDU table and footstool The equipmentwas adjusted so that each subject was in a posture which gave a RULA score of 1 for the first experimentalcondition. For the second condition, the screen wasplaced on the table so that it caused 20” or more neck flexion; the kevboard was placed so that the forearmswere flexed mire than 90”. the right wrist was extendedand in ulnar deviation. In addition, the foot supportwas removed.The task required data entry only, using the right- side number pad. The data for keying were presentedon the screen to control for neck posture changes.Before starting and at the completion of each task thesubjects marked any areas of pain, ache or discomfortthey were experiencing on a body map based on the Corleit and Bishop body part discomfort (BPD)method’ I. Recording of RULA was conducted 15 minafter

7 starting the task when the operator had
starting the task when the operator had settledinto a working rhythm and posture. The right side ofthe body wasevaluated, highermusculoskethat was the arm experi- al loading.Individual body partsFor each of the body parts, (neck, trunk, upper arm.lower arm and wristjthe RULA scores were dividedinto two groups. The operators with a posture score of 1, which is defined as an acceptable working posture.were put in the first group. The second group includedall other operators regardless of how high their posturescore was. While postural discomfort is frequently usedas a guide to evaluating working postures and work-place fit, there is a wide variation in the length of timebefore operators perceive discomfort and in the level ofdiscomfort which thev report. To have conducted thesetrials over a longer period would have provided higherscore:; however, it is known that operators adjust theirworking post&e to relieve loading on areas wnicti areuncomfortable. A large number of subjects wouid havebeen required if this study was to test the relationshipof the magnitude of a RULA score to the magnitude ofpain, ache or discomfort. The aim of this study was toestablish if the RULA scoring could reflect whether ornot a working posture was in the acceptable range asdefined earlier.The x2 statistical test was used to determineassociation between the subject’s score defined bygrouping and any reported pain, ache or discom from that body part region. The results are givei Table 3. the The relationship of the individual RULA body partscores to the development of pain or discomfort isstatistically significant for the neck and lower armscores (P 0.01) and not significant for the trunk,upper arm or wrist scores.The statistical significance of the neck and lower armbody part scores reflects the high loading of these bodyparts while performing a VDU-based task. Function-ally, the neck-shoulder region experiences static musclefatigue contributed to by the load of the arms and theirposition” .The lower arm region includes the musclesand associated soft tissue structures responsible for theposture and action of the wrist, hand and fingers. Thetask required constant keying so that the structures inthe neck and shoulder region were performing a staticposture function while the structures of the forearmperformed high repetition rate and low force fingermovements with no recovery period over the 40 mintrial. With these experienced data-entry subjects theloading of these structures was sufficient to causereporting of discomfort or pain of a significant level.Further studies of other tasks commencing with cash till operators are planned to evaluate the different associa-tions of individual body part discomfort with themusculoskeletal loading from the working posturesadopted. Functional units Assessing the effect of loading in all the structureswhen grouped as functional units would be achieved byrelating posture scores A and B to the reporting ofpain, ache or discomfort in the whole region. A y2 statistical test was again used and the operators’ rest& were grouped according to whether there was a posturescore of 1 or a score greater than ! for both A and B scores. There was a highlv significant association (P 0.01) between both posture scores A and B andreported pain or discomfort in the relevant functionalunit regions (see Table 4).The high statistical significance of the relation Vol 23 No 2 April 1993 97 RULA: a survey method for the investigation of work-related Table 3 x2 statistical analysis of the RULA body partscores (1 or � I) and the reported pain, ache ordiscomfort in that region Posture “1 �f No pain 11.9 37.8 7 (1 df) o Ol 12.5 83.2 * pain 13.8 17.5 o j cl df) 26.3 42.5 - No pain16.914.441.9 No pain16.914.449.4 No pain35.20.5 Table 4 x2 statistical analysis of the RULA body partscores (1 or � 1) and the reported pain, ache ordiscomfort in that region Score AScore B 1 No pain20.834.2 (1 df)12.1(1 df)

8 P Application of RULADuring the period
P Application of RULADuring the period in which RULA underwentvalidation tests it was used in both industrial and officesettings by ergonomists from the Institute for Occupa-tional Ergonomics and by physiotherapists who attendedintroductory courses in ergonomics. Specific operations _. I&JLA wa’s re$Z%ted as a usefu$ assessment tool 9 include a variety of hand and hachine packing opera-tions, VDU-based tasks, garment-making operations,supermarketcheckout operations, microscopy tasksand operations in the car manufacturing industry.Once the users were familiar with RULA theyreported that it was quick and easy to use. RULA wasfrequently reported as being useful when presenting theconcept of musculoskeletal loading due to work, inmeetings with management. Managers were quick torecognize and remember the grand scores and theirassociated action levels. This was reported as beinghelpful in the communication of problems, decidingupon the priority for investigations and the changes tobe conducted in the workplace. In addition, RULA wasfound particularly valuable in reassessing any changesin musculoskeletal loading after modifications had beenintroduced to the work and workstation.As noted earlier, if a comprehensive assessment ofthe workplace is to be made, RULA should be used aspart of a larger ergonomics study covering epidemi- physical, mental, environmental and organiza-tional factors.A more complete methodology toidentify and investigate work-related upper limb dis-orders, which includes RULA, has been produced bythe Institute for Occupational Ergonomics”‘. Conclusions between posture scores A and B with the regional pain,ache and discomfort indicates that the RULA scoring issensitive to the changes from an acceptable to anunacceptable working posture based on the criteriawhich have been set out in the development of RULA.It also reinforces the importance of assessing the wholeregion as well as the individual body parts because theimpact of musculoskeletal loading has importantconsequences foi- the function of the unit as a whole.For a test of its reliability, RULA was presented as amethodology during the training of over 120 physio-therapists. industrial engineers, safety and productionengineers. Videotaped examples of operators perform-ing screen-based keyboard operations, packing, sewing and brick sorting were shown and each subject completed a RULA asse?qment. Comparison of thei,r results indicated a high consistency of scoring amongst’subjects. Discrepancies only occurred when a body segmentposture was at a border between two ranges, usuallywhen assessing the lower arm posture. As a consequ-ence, the lower arm ranges were subsequently adjustedfrom the original version (a score of 1 being O-90” and ascore of 2 being 90” or more range of movement) to thepresent svstem reported here.RULA was developed to provide a rapid assessmentof the loads on the musculoskeletal system of operatorsdue to posture,muscle function and the forces theyexert. It is designed to assess operators who may beexposed to musculoskeletal loading which is known tocontribute to upper limb disorders. RULA fulfils therole of providing ‘a method for screening a iarge number of operators quickly, but the scoring systemdeveloped also provides an indication of the level ofloading experienced by the individual body parts.RULA is used without the need for any equipmentand, after training in its use, has proved a reliable toolfor use by those whose job it is to undertake workplaceassessments. It can be used as a screening tool orincorporated into a wider &gonomics assessment ofepidemiological, physical, mental, environmental andorganizational factors. B J *Work-related musculoskeletal disorders ofthe neck and upper extremities in workers engaged inlight, highly repetitive ivork’ in Osterholz, U, Karmaut;, B and Ritz, B (eds) Proc related Muscrrloskeletal Disorders, Bonn (1987) pp L MCATAMNEY AND E N CORLE-IT 2 Vihma, T, Nurminen, M and Mutanen, P ‘Sewing

9 machine operators’ work and musculo
machine operators’ work and musculoskeletal complaints’ Ergo-nomics Vol 25 (1982) pp 295-2983 Kilbom, A, Persson, I and Jonsson, B G ‘Risk factors forwork related disorders of the neck and shoulder - withspecial emphasis on working postures and movements’ in Corlett, E N, Wilson, J R and Manenica, J (eds) The ergonomics of working posture Taylor & Francis, London(1986) pp 44-53. * 4 Wick, J and Drury, C G ‘Postural change due to adap-tations of a sewing workstation’ in Corktt, E N, Wilson,J R and Manenica, I (eds) The ergonomics of workingpostures Taylor & Francis, London (1986) pp 375-379 5 Blider, S, Barth Holst, U, Danieisson, S, Ferhn, E,Kalpamaa, M, Leijon, M, Lindh, M, Markhede, G andMikaelsson, B ‘Neck and shoulder complaints amongsewing-machine operators’in Buckle, P (ed) Mwculo- skeletal disorders at work Taylor & Francis, London, (1987) pp 110-111 motion injury potential of industrial jobs’ Semin OccupMed Vol 2 No 1 (1987) pp 41-4716 Tichauer, E R ‘Some aspects of stress on forearm andhand in industry’ J Occup Med Vol 8 (1966) pp 63-7117 D B ‘Localized muscle fatigue - definition andmeasurement’ J Occup Med Vol 15 (1973) pp 34635418 Herb&s, P, Kadefors, R and Broman, H ‘Arm position-ing in manual tasks.An electromyographic study of -=j_ iised muscle fatigue’Ergonomics Vol 23 (1980)pp 19 Hagberg. M ‘Electromyographic signs of shouldermuscular fatigue in two elevated arm positions’ Am J Med Vol 60 (1981) pp 111-1216 Hagberg, M Occupational shoulder and neck disordersReport No. 40-19-17, The Swedish Work EnvironmentFund, Stockholm (1987) 20 Schuldt, K, Ekholm, J, Harms-Ringdahl, K, Arborelius, U P and Nemeth, G ‘Influence of sitting postures on neck and shoulder EMG during arm-hand work movements’ Clin Biomech Vol 2 (1987) pp 12613921 HarmsRingdahl, K and Schiildt, K ‘Neck and shoulderload and load-elicited pain in sitting work postures’ inBullock, M (ed) Ergonomics: the physiotherapist in theworkplaceChurchill Livingstone, Edinburgh (1990) pp 133-148 7 Aa&, A ‘What is an acceptable load on the neck andshoulder regions during prolonged working periods?’ inKumashiro, M and Megaw, E D (eds) Towards humanwork Taylor Francis, London, (1991) pp 115-125 8 Moore, A, Wells, R and Ranney, D ‘Quantifying exposure in occupational manual tasks with cumulative traumadisorder potential’Ergonomics Vol 33 No 12 (1991)pp 22 Grandjean, E Fitting the task to the man Taylor & Francis,London (1988) pp 24, 48, 51, 10723 Health and Safety Executive Guidelines on the preventionof work related upper limb disorders HMSO, London (1990) 9 Kourinka I, Jonsson, B, Kilbom, A, Vinterberg, H, Biering-Sorenson, F, Andersson, G and Jorgensen, K‘Standardised Nordic questionnaires for the analysis ofmusculo-skeletal symptoms’ Appl Vol 18 (1987)pp 10 Kemmlert, K and Kibom, ‘Method for the identification effects’ National Board of Occupational Safety andHealth. Research Department, Work Physiology Unit,Solna. Sweden (1986)11 Corlett, E N and Bishop, R P ‘A technique for assess-ing posturaldiscomfort’ Ergonomics Vol 19 (1976)pp 12 Karhu, 0, Kansi, P and Kuorinka, I ‘Correcting workingpostures in industry, a practical method for anlaysis’ Appl Vol 8 (1977) pp 199-201 24 Tichauer, E R ‘Ergonomics sustains occupational safetyand health’ Ind Eng Vol 8 (1976) pp 4546 25 Kilbom, A, Persson, I and Jonsson, B G ‘Disorders of thecervicobrachial region among female workers in theelectronics industry’ i’nt J Ind Vol 1 (1986) pp 374726 Grandjean, E, Hunting,W and Piderman, M ‘VDTworkstation design: preferred settings and their effects’Hum Factors Vol 25 (1983) pp 161-17527 Chaffin, D B and Andersson, G B J Occupational bio- mechanics John Wiley & Sons, New York (1984)28 M and Jonsson, B ‘Endurance limit of force inlong-term intermittent static contraction’ J WorkEn

10 viron Health, Vol 3 (1977) pp 23-27 29
viron Health, Vol 3 (1977) pp 23-27 29 Jonsson B ‘Measurement and evaluation of local muscularstrain in the shoulder during constrained work’ J Hum 11 (1982) pp 73-8830 V Cumulative trauma disorders. A manualfor musculoskeletal diseases of the upper limbs Taylor & Francis, London (1988) p 62 13 Corlett, E N Static muscle loading and the evaluation31 Stevenson, M G, and Baidya, K ‘Some guidelines onof posture’ in J R and Corlett, E N (eds)repetitive work design to reduce the danger of Evaluation of human work Taylor & Francis, Londonsynovitis’ in Stevenson, M G (ed) Readings in RSI. The(1990) pp 570 14 Wrigley, ergonomics approach to repetition strain injuries New T V, Green, R A and Briggs, C A ‘Micro-South Wales University Press, Sydney (1987)computer video image processing technology in working32 L and Corlett, E N The identification andposture analysis’ Appl Voi 22 No 1 (1991) pp 2-9investigation of work related upper limb disorders Institute G ‘A biomechanical evaluation of the repetitivefor Occupational Ergonomics. Nottingham (1992) 99 Source: McAtamney, L. & Corlett, E.N. (1993) RULA: a survey method for the investigation of work-related upper limb disorders, (2) 91-99. Professor Alan Hedge, Cornell University. Feb. 2001 to +20 to 100 + +2 to 45o� -20o+1++4+2 Final Wrist Score = Wrist Twist Score = UpperLowerArmArm1234Wrist TwistWrist Twist Wrist Twist Wrist Twist12121212111222233322222333332323334421222333442222333443233334453123334455223334455323344455413444445523444445533445556651555556672566667773666777786177777889278888999399999999 UpperLowerArmArm Step 5: Look-up Posture Score in Table AStep 4: Wrist TwistIf wrist is twisted mainly in mid-range =1;If twist at or near end of twisting range = 2+FINAL SCORE: 1 or 2 = Acceptable; 3 or 4 investigate further; 5 or 6 investigate further and change soon; 7 investigate and change immediatelyIf shoulder is raised: +1;If upper arm is abducted: +1;If arm is supported or person is leaning: -1If posture mainly static (i.e. held for longer than 1 minute) or;If action repeatedly occurs 4 times per minute or more: +1Step 8: Find Row in Table CMuscle Use Score ==Final Neck ScoreThe completed score from the Neck/Trunk & Leganalysis is used to find the column on Chart CStep 12: Look-up Posture Score in Table B erocSerutsoPknurT geL geL geL geL geL geL ceN Step 2a: Adjust…If arm is working across midline of the body: +1;If arm out to side of body: +1Final Upper Arm Score = +1+1+1+1+1+1+1+3+2+2+0o+0 +1+2to 60 Step 2: Locate LowerArm PositionFinal Lower Arm Score = +If wrist is bent from the midline: +1 Step 6: Add Muscle Use Score Step 7: Add Force/load ScoreIf load less than 2 kg (intermittent): +0;If 2 kg to 10 kg (intermittent): +1;If 2 kg to 10 kg (static or repeated): +2;If more than 10 kg load or repeated or shocks: +3 = The completed score from the Arm/wristanalysis is used to find the row on Table CFinal Wrist & Arm Score =Step 3: Locate Wrist PositionStep 3a: Adjust… Table B10 to 20o0oin extensionComplete this worksheet following the step-by-step procedure below. Keep a copy in the employee's personnel folder for future reference. +1+2+3 +4 1234567+112334552223445533334456433345665444567764456677755667778+5567777 Table C RULA Employee Assessment Worksheet Department:Scorer: Step 1a: Adjust…Step 1: Locate Upper Arm PositionA. Arm & Wrist Analysis B. Neck, Trunk & Leg Analysis 20+ Step 13: Add Muscle Use Score Step 14: Add Force/load Score Step 15: Find Column in Table C+=+ Step 9: Locate Neck PositionStep 9a: Adjust…If legs & feet supported and balanced: +1;If not: +2If trunk is twisted: +1; If trunk is side-bending: +1If neck is twisted: +1; If neck is side-bending: +1Use values from steps 8,9,& 10 to locate Posture Score inIf posture mainly static or;If action 4/minute or more: +1If 2 kg to 10 kg (intermittent): +1;If 2 kg to 10 kg (static or repeated): +2;If more than 10 kg load or repeated or shocks: +3= Force/load Score= Muscle Use Score= Posture B Score= Final