1 Job Analysis and Work Assessment Readings – Jackson – Ch 14 - Louhevaara – Ch 70 - Anderson – Ch 72 - Key

2 Introduction - general outcomes and applications Job analysis Introduction Variables that influence performance methodology Applications (assessment) Fitness Job placement Assessment Functional Capacity Assessment Validity of job analysis / Assessment Outline

3 It is important to know what we are demanding from an individual in a work (or sport) situation –Ensure performance demands do not exceed capabilities Relates to ; –Injury prevention –Job performance –Maintenance of work ability Information is utilized for –Job redesign / ergonomic intervention –Development of valid cutoff scores for job placement assessment (JPA) –Assessing functional capacity for return to work following injury (FCA) Detailed job analysis will provide us with the necessary information Job Analysis and Work Assessment

4 Goal is to identify the important work behaviours Reduce job actions to words –essential component in developing pre employment test JA utilizes a combination of approaches that include gathering –Psychophysical data –Biomechanical data –and physiological data Methods may include –Questionnaires, checklists and surveys –interviews / Observations –Video analysis –Task simulations –Measurements (weight, height, EMG, HR, VO 2, distance) Job Analysis

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6 Psychophysical –Worker rates tasks on survey or performs simulations –RPE - rate of perceived exertion - Borg or Likert scales –Perception in terms of - CV demand, movement quality and strength (general / localized) Biomechanical methods –heights and weights of objects lifted –forces - opening, pulling, pushing –evaluate potential stress on lower spine –video or physical evaluations of simulations Physiological - CV components, blood analysis –O 2 use, HR, [lactate], pH, [hormone], [ion], [ATP], [CP] Job Analysis - Methods

7 BORG Scales Old BORG RPE SCALE New BORG RPE SCALE %HR Max%VO 2 max Very,very light.5Very,very weak 1Very weak 9 10 Very light2weak 3moderate Fairly light 4Somewhat strong Strong Somewhat hard Hard7Very strong Very Hard Very,Very Hard 10Very Very Strong Maximal

8 Pre-employment tests are used to reduce work injuries –some jobs - high low back injuries –not serious but prevalent - 80% –lifting, twisting, bending, pulling 3 Ergonomic approaches to reduce back injuries – job Redesign Engineering approach to reduce exposure to risk factors –pre employment testing Preferred approach for physically demanding jobs that cannot be redesigned Select individuals with capacity to safely perform job Relationship between probability of injury and the % of capacity to perform task –education and training Train to lift properly - not successful Injury Rates

9 when redesign is not feasible, fitness becomes important secondary preventative measures –individual health promotion –healthy satisfying lifestyle –maintaining work ability / healthy aging –Fitness training / nutrition Job demands and Physical Fitness

10 Affected by - % use of strength, frequency of peak loading, work/rest ratio, environmental factors, intensity level of strain depends on demand and individual capacity optimal / acceptable demand –cardio, muscular and psychosocial strain –physiological changes –fatigue –specific local changes (small muscles) if job demands –do not exceed capacity - adaptation –too high - fatigue, dec productivity –prolonged / repetitive - damage / injury Muscular work at the proper intensity, frequency and duration will produce fitness training effects Physical work load

11 Fig 14-3 dimensions of Fitness –CV capacity (aerobic, anaerobic) –muscular performance –motor coordination based on physiological demands and Anthropometric characteristics –Utilization of capacity requires voluntary control - therefore all linked to MOTIVATION –optimal situation - harmony between demand and fitness Situation is highly dynamic Text looks at specifics of Police, Fire and Professional Cleaners Physical Fitness

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13 Fitness level appears to be inversely related to injury –High levels of aerobic fitness, strength and flexibility were inversely related to workers compensation costs of fire fighters Fitness programs should reduce musculoskeletal injuries –Only % of employees will use work site exercise facilities –Only 33% of these will train at the appropriate frequency, duration and intensity Fitness and Injury

14 Physical exercise is one of the basic elements in maintenance of work ability –linked with productivity, quality of work, absenteeism, and turnover rate –Exercise programs must be tailored to job demands successful intervention requires –commitment and support management and staff –use of work time (for at least part) –feedback and strong motivation –positive experience with exercise –skill full instruction –confidential, voluntary and no guilt Fitness and Productivity

15 Ch 70 - Anderson Ergonomics - alter the demands of the job to match the worker-redesign Alternative approach is to match workers to the job, based on physical abilities –decline of 20-40% in injury rates when physical ability testing is implemented Effectiveness depends on ability of test battery to assess what it intends requires –thorough job analysis –carefully chosen job placement tests - measure only taks deemed essential by job analysis –validation that tests predict performance on the job courts prefer testing to be focused on ability to perform not injury risk Physical Ability Testing

16 Cost / Benefit of Testing –cost of not being able to perform task –probability of individual lacking ability Use normative data bases for different components. Use of standard protocols necessary –balance with cost of testing applicants –Would it be more cost effective to redesign job? Assessment

17 Test Battery Design –test requires a high degree of relatedness to essential function –Use realistic cutoff scores and normative data –accurate - precisely measures attribute it says it measures –reliable - yields same results over time and by different testers objective rather than subjective tests –All applicants must be treated fairly all must be tested after same preparation and awareness same re-testing procedures Assessment

18 Workers’ compensation costs can be very high Knowledge of worker functional capacities important to reduce these costs Knowing workers capacity is important –For decision to hire (JPA) –For decision to return to work (FCA) Fig Key FCA- Functional Capacity Assessment –return to work testing process –individual physical functional work related capability –confirmation of meeting or not meeting minimum physical requirements goal of FCA is return to work ASAP - even if limited capacity, some pain - may be modified tasks initially Assessment of Worker Capacities

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20 Provides data prior to hiring –assists managers - reduce injuries JPA - specific, objective, standardized protocols accurate and repeatable –Identify employees capability for lifting, carrying, pushing, pulling… Goal - accurately match worker with job Components of assessment fig 72-2 –weighted capabilities - CV, posture –tolerance and endurance capabilities establish safe limits for work day –Validity of participant - honesty –fig less dishonest than generally assumed (5%) utilize database correlation to confirm push vs pull, HR response at exertion Job Placement Assessment (JPA)

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22 Principles for selecting FCA –must contain standards for identifying validity of participation –methodology must be consistent –utilize standard equipment –administrators must be trained and objective –processing of results must be standardized Fig 72-5 –reports should compare results with demands of job –unbiased and defendable decision about return to work Worker Assessment Principles

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24 FCA - dec re-injury rates –decrease lapse of time before return to work –decrease incidents and costs JPA - reduce injury and lost days –eg fig 72-6 paper manufacturer –pre and post JPA implementation Outcomes

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26 Determine whether test actually measures important work behaviors Validity depends on reliability and relevance –Reliability - ability to differentiate among true levels of performance –Relevance - defining qualities being tested Content validity –work sample or simulation of work –Test represents the content of the job Relevance is clear and logical –Disadvantages - safety, not maximal capacity Validation Strategies

27 Criterion related validity –Criterion - standard of judgment –Test successful people to determine what is required - use this to develop standards for success –significant correlation between pre employment test and job performance –Concurrent / predictive Statistical validity –prospective - test individual applicants - do not use results in hiring - analyze performance of all individuals hired productivity, retention, injury rate, evaluation –Compare to assessment results –Fig injury rate twice as high in those who failed screening test Or, implement test in hiring practice, and compare to those hired previously –lack of control for other factors Validation Strategies

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29 Construct Validity Establish that a construct is required for job success Use test that measures that same construct The degree to which a test measures an attribute that cannot be directly measure (coordination) link important constructs and multiple indicators of job performance –Tests theoretical and empirical relationships –Relationship between physical ability and job Eg, biceps used to lift box, test bicep strength using barbell, establish cutoff based on weight of boxes FDNY physical ability test was found to discriminate against women as constructs were not related to the job Validation Strategies

30 Cut Score –The test score that an applicant must obtain to be considered for a job –Difficult to establish and justify –Should they be relative to capacity, or absolute? –Should someone be hired who just meets the minimal requirement? General Recommendations –Cardiovascular - max of 40% of VO 2 max for 8 hr day If peaks are higher, work / rest should be designed to keep average below 40 % –Evaluate large number of subjects If 75% rate as acceptable, dec injury by 33% –Muscle work - Snook and Ciriello (1991) Table 21.2 (Gallagher) Cut off scores

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32 Employers are using pre-employment tests to ; –enhance worker productivity – to minimize the threat of litigation for discriminatory hiring practices – and to reduce the risk of musculoskeletal injuries. The most common reason for ruling an employment practice invalid is the failure to show that the test measured important job behaviours. Proper job analysis will help ensure validity. Summary

33 Muscular Function Assessment Gallagher - OEH Ch 21(CCW)

34 Muscle strength is a complex function that can vary with the methods of assessment Definitions and introduction Assessment methods Variables impacting performance Outline

35 Gallagher Strength - capacity to produce a force or torque with a voluntary muscle contraction Power - Force * distance * time -1 Endurance - ability to sustain low force requirements over extended period of time Measurement of human strength –Cannot be measured directly –interface between subject and device influences measurement –Fig 21.1 Biomechanical eg. Q = (F * a)/b or c or d force from muscle is always the same results are specific to circumstances dynamic strength - motion around joint –variable speed - difficult to compare static or isometric strength- no motion –easy to quantify and compare –not representative of dynamic activity Muscle Function

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37 Gender Age Anthropometry Psychological factors - motivation –table 21.1 Factors Affecting Strength

38 Task influence –Posture fig angle and force production –Duration - Fig 21.3 –Velocity of Contraction - Fig 21.4 –Muscle Fatigue –Static vs dynamic contractions –Frequency and work / rest ratio –Temperature and Humidity inc from C - decrease of 10-20% in muscle capacity Factors Affecting Strength

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42 Isometric strength testing –standardized procedures –4-6 sec contraction, sec rest –standardized instruction posture, supports, restraint systems, and environmental factors –worldwide acceptance and adoption Dynamic strength –isoinertial (isotonic)- mass properties of an object are held constant –Psychophysical - subject estimate of (submax) load - under set conditions –isokinetic strength through ROM at constant velocity - no acceleration or deceleration Uniform position on F / V curve Standardized Isolated muscle groups Research and rehabilitation Strength Testing (intro)

43 Testing for worker selection and placement –Used to ensure that worker can tolerate physical aspects of job –similar rates of overexertion injuries for stronger and weaker workers Key principles –Strength test employed must be directly related to work requirements must be tied to biomechanical analysis Isometric analysis fig 21.5 –for each task - posture of torso and extremities is documented (video) recreate postures using software Free body diagrams (Kin 201) –values compared to pop. norms industrial workers –estimate % capable of level of exertion –predict stress on lumbar spine Strength Testing

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45 Discomfort and fatigue in isometrics thought to result from ischemia –Increasing force, increases intramuscular pressure which approaches then exceeds perfusion pressure - lowering then stopping blood flow –Partial occlusion at 20-25% MVC –Complete occlusion above 50% MVC Fig Astrand –Max hold time affected by % MVC –Recommend less than 15% for long term requirements Fig Astrand –With repeated isometric contractions Force and Frequency influence endurance –Optimal work / rest ratio of 1/2 –Duration important as well (Astrand - blood flow) Isometric Considerations

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47 Consider - biomechanics and grip –Stabilization requirements –justification of cut off scores Examples from industry SAT - strength aptitude testing –air force standard testing –Pre-selected mass - increase to criterion level - success or failure –found incremental weight lifted to 1.83m to be best test as well as safe and reliable PILE - progressive inertial lifting evaluation –lumbar and cervical lifts -progressive weight - 4 lifts / 20 seconds standards normalized for age, gender and body weight –variable termination criteria voluntary, 85 % max HR, 55-60% body weight Isoinertial Testing

48 psychophysical methods –workers adjust demand to acceptable levels for conditions –provides ‘submax’ endurance estimate Procedure - –subject manipulate one variable-weight –Either test : starting heavy or light –add / remove weight to fair workload –Fair defined as : without straining, becoming over tired, weakened, over heated or out of breath Study must use large number’s of subjects –evaluate/design jobs within capacities of workers –75% of workers should rate as acceptable If demand is over this acceptance level; 3 times the injury rate observed to occur Psychophysical testing

49 Summary –Table 21.2 (Snook and Cirello) (see slide 31) Advantages –realistic simulation of industrial tasks –very reproducible - related to incidence of low back injury Disadvantages –results can exceed “safe” as determined through other methodology –biomechanical, physiological Psychophysical (cont)

subjects - asked about job demands of physical fitness and aerobic power, muscular performance and motor coordination –smoke diving with SCBA- highest aerobic demand –clearing passages with heavy manual tools - most muscular demand –roof operations- highest motor control demand Aerobic Power Demand then assessed- Table 14-1 –often L/min –max frequent 3.8 L/min 180 bpm –compounded by need to disperse heat no possibility of alleviating load –recommend minimum of ml/min/Kg for VO 2 max Fire Fighters

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52 Muscular Performance –biomechanical factors - simulated clearing task - 9 kg power saw - floor to ceiling –high compression on L5/S1 –~ 90 % of isokinetic strength –back and knee extensors Table determined that a minimum of good or excellent is needed for muscular performance measures –Bench press –Sit up –Squat –Pull up Fire Fighters