Job Analysis and Work Assessment

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

2. Outline • 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

3. Job Analysis and Work Assessment • 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

4. Job Analysis • 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, VO2, distance)

6. Job Analysis - Methods • 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 • O2 use, HR, [lactate], pH, [hormone], [ion], [ATP], [CP]

7. BORG Scales

8. Injury Rates • 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

9. Job demands and Physical Fitness • 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

10. Physical work load • 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

11. Physical Fitness • 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

13. Fitness and Injury • 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 20-40 % of employees will use work site exercise facilities • Only 33% of these will train at the appropriate frequency, duration and intensity

14. Fitness and Productivity • 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

15. Physical Ability Testing • 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

16. Assessment • 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?

17. Assessment • 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

18. Assessment of Worker Capacities • 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 72-1 - 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

20. Job Placement Assessment (JPA) • 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 72-3 - less dishonest than generally assumed (5%) • utilize database correlation to confirm • push vs pull, HR response at exertion

22. Worker Assessment Principles • 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

24. Outcomes • 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

26. Validation Strategies • 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

27. Validation Strategies • 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 70-1 - 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

29. Validation Strategies • 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

30. Cut off scores • 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 VO2 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)

32. Summary • 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.

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

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

35. Muscle Function • 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

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

38. Factors Affecting Strength • Task influence • Posture • fig 21.2 - 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 20-27 C - decrease of 10-20% in muscle capacity

42. Strength Testing (intro) • Isometric strength testing • standardized procedures • 4-6 sec contraction, 30-120 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

43. Strength Testing • 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

45. Isometric Considerations • 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 15-19 Astrand • Max hold time affected by % MVC • Recommend less than 15% for long term requirements • Fig 15-20 Astrand • With repeated isometric contractions Force and Frequency influence endurance • Optimal work / rest ratio of 1/2 • Duration important as well (Astrand - blood flow)

47. Isoinertial Testing • 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

48. Psychophysical testing • 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

49. Psychophysical (cont) • 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

50. Fire Fighters • 200 subjects - asked aboutjob 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 2.1-2.8 L/min • max frequent 3.8 L/min 180 bpm • compounded by • need to disperse heat • no possibility of alleviating load • recommend minimum of 34-45 ml/min/Kg for VO2max