2. Update to the 3D SSPP Users Guide Jason Beardsley & Bob Fox

3. Sections with Changes or Additions  Selecting Anthropometry  Wrist Moments  Lower Extremity Manipulation and Interpretation  Animation

4. Selecting Anthropometry

5.  UAW-GM agreement on anthropometry: –95 th percentile female (stature of 68 inches); –Enter body weight of 200 lb.  Acceptable percent of population capable for strength remains at 75% or above for the wrist, elbow, torso and shoulder.

6. Wrist Moments  Wrist posture (horizontal and vertical angels) may be adjusted to obtain a realistic hand posture as part of an analysis.

7. Wrist Moments  Do not use 3D to analyze repetitive hand motion activities (use HAL/TLV).  The wrist strength data used in 3D is compiled from a variety of sources and sometimes glitches may appear in the wrist moments presented on the Strength Capabilities report.

8. Animation  The animation capability allows for multiple postures to be stored in one 3D task file and can animate motion between postures using frame by frame interpolation.  it does not provide a dynamic analysis of the task and should not be used to draw conclusions about the strength demands of jobs.

9. Lower Extremity Manipulation and Interpretation  3D version 6.04 and above provide for horizontal angles on the lower extremity which can improve the posturing of the manikin.  the lower extremity horizontal angles are not posture predicted and any adjustment will have to be by the analyst.  Also, only flexion and extension moments are produced for the ankle, knee and hip.  For these reasons the percent capable strength indications for the hips, knee and ankle should be ignored.

12. Review of 3D SSPP and Recovery Tool

13. Purpose of the UAW-GM Recovery Tool  To calculate the rest/recovery time needed to avoid cumulative local muscle fatigue using the following: –Amount of time in static posture per IE line balance tools (per ALBS, APS, etc.) –Required moment and population mean strength for posture per 3D SSPP™. 13

14. Strategy of Use  The Recovery Tool requires exertion time, exerted force and population strength data as inputs.  As such, the Recovery Tool is used in conjunction with the University of Michigan 3D Static Strength Prediction Program™ in the course of conducting an analysis.  Both tools are used with a standard analysis and interpretation strategy.

15. Background and Development of the Recovery Tool  “Excessive force” continues to be a problem in many cyclical work operations. This may involve the prolonged or static exertion of force and/or the holding of a stressful posture  Static force exertions/postures with inadequate recovery time leading to cumulative muscular fatigue are identified as a risk factor in the onset of various musculoskeletal injuries and illnesses.  To address this issue and expand on our capability in assessing job strength demands, experimentation was performed with simple spreadsheet versions of the Rohmert equations.

16. Rohmert’s Rest Allowance Equation

17. Enhancements to the Recovery Tool  An article by Swedish researcher Linda Rose (Ergo-Index – A model to determine pause needs after fatigue and pain reactions during work, 1992), led to the consideration of additional equations to assess recovery for static muscle loading of less than 15%.  Based upon Rose’s work, the Rose recovery equations were used for static muscle loading ≤ 15% MVC while the Rohmert equations were used for > 16% MVC.

18. Improvements to the Tool: Inclusion of Equations for Overhead Work  In the late 1990s, the American Automobile Manufacturers Association (AAMA) funded research into the overhead work fatigue and injury issues.  One funded study by A. Garg (Physiological and Psychophysical Measurements of Muscle Fatigue and CTDs for Short-Cycle Overhead Work, 1999).  Garg determined recovery times for arm postures derived from endurance time best-fit power function prediction equations.

19. Recovery Tool Assumptions  “Recovery” refers to specific muscle group recovery that occurs within the job cycle.  The “specific muscle groups” refer to the upper extremity muscle groups given on the 3D SSPP Strength Capabilities report screen.  The exertion is static as opposed to dynamic and must be held for at least several seconds.  For multiple exertions, the same muscle group is analyzed across the exertions. Muscle groups are not mixed in the same analysis.  Analysis should start with the most loaded muscle groups per the 3D SSPP™ Strength Capabilities report (i.e., lowest percent capable).

20. What Triggers the Use of the Recovery Tool?  A “flag” raised by one of a number of screening tools will trigger a review that could result in the use of the Recovery Tool.  Several questions on the RFC map to the Recovery Tool: –Trunk Posture section, especially question 8. Severe forward bending more than 45°. –Upper Extremity Question 14. Is an elbow used at or above mid-torso level (30 degrees flexion or abduction)?  In general, prolonged force exertions – holding a posture or maintaining an exertion for a protracted period (more than several seconds).

21. Limitations of the Tool  The UAW-GM Recovery Tool is sophisticated in the sense that it incorporates equations to address a full range of Relative Force and special equations for some aspects of overhead work.  It also includes strategies for assessing multiple exertions within a job cycle depending upon the pattern of the exertions.  However, muscle physiology and recovery is complex and any complex pattern of exertions will drive the tool to the limits of inference. There remains an element of judgment in the use and interpretation of the tool.

22. Two Versions of the Tool Quick Tool Complete Analysis Tool

23. Quick Tool  Use for most cases of single exertions.  Enter the Required Moment (m), Population Mean Strength (M) and exertion time for the joint being evaluated.  Program returns the relative force, maximum hold time and applicable recovery time.

24. Complete Analysis Tool

25. General Instructions on Using the Tool 1.Review Standardized Work (APS, etc) to determine amount of time in the stressful posture being analyzed. This value is the Exertion time (t). 2.Perform a static strength analysis using 3D SSPP™ for each distinct posture or forceful exertion. Identify the Required Moment and the Population Mean Strength.

26. General Instructions on Using the Tool 4.Enter information from Instruction 3 along with Exertion time (t) into the Quick Analysis Tool or the Complete Analysis Tool. Quick Analysis Tool – Single exertions Complete Analysis Tool – Multiple exertions, overhead work

27. General Instructions on Using the Tool 5.Multiple rest equations are contained in this spreadsheet (Rohmert, Rose & Garg) and the program returns a 'NA' if a particular equation is not appropriate for use.

28. Two Options for Multiple Exertions  If two (or more) exertions are similar and performed with very little or no time between exertions, then analyze each exertion separately and put the info in the Multiple Exertion Matrix.

29. Two Options for Multiple Exertions performed  If two or more exertions are performed with opportunity for recovery between exertions then analyze each exertion one at a time in the Multiple Exertion Matrix and put the info for each exertion along with its individual recovery time into the Total Operation Review Matrix. Consult Notes 1 & 2 in the program for more info

30. Overhead Work  If the work task is overhead and the exertion intensity is less than a RF of 0.44, determine vertical angle of upper arm & included angle of the elbow. See diagrams below.

31. Overhead Work  Then use the calculated Recovery time from the OVERHEAD WORK RECOVERY CALCULATIONS section.  If the exertion intensity is greater than a RF of 0.44, use the Rohmert Recovery Time in cell I11 of the Complete Analysis Tool tab.

32. Accept/Reject Decision Guidelines  For a single static exertion: –Accept if the Recovery Time (RT) plus the exertion time is less than the total cycle time of the operation.  For multiple static exertions: –Accept if the Total Recovery Time (TRT) (sum of the recovery times generated from each exertion analysis) plus the cumulative exertion time in a stressful posture is less than the total cycle time of the operation (see Total Operation Review matrix in lower left corner of Complete Analysis Tool.

33. Review of Energy Expenditure Prediction Tool

34. Snook Tables Program NIOSH Lifting Program 3D SSPP Energy Expenditure Program Analysis Decision UAW-GM RFC2 Upper Extremity Section Energy Expenditure Section Manual Lifting Section Posture Section

35. SUPPLEMENTAL NOTE 1. No - The worker does not... Walk and Carry Requirements ENERGY EXPENDITURE NoYes Tasks 1.Is the operator required to walk more than 40 steps (100 ft.) per minute, while carrying more than 5 lbs?  H ________ Page 11 of 18

36. SUPPLEMENTAL NOTE 2. No - The worker does not... Climbing Requirements No Sometimes Usually Task(s) 2. Does the worker climb up and/or down repeatedly?  4 H _____ Page 11 of 18

37. SUPPLEMENTAL NOTE 3. No - The worker maintains... Bend and Stoop Requirements No Sometimes Usually Task(s) 3. Does the worker bend or stoop below the knees repeatedly?  4 H ________ Page 11 of 18

38. SUPPLEMENTAL NOTE 4. No - Definition of respirator... Use of Respirators No Sometimes Usually Task(s) 4. Is a respirator worn?  H H ________ Page 11 of 18

39. SUPPLEMENTAL NOTE 5. No - Worker is never exposed... Heat Exposure No Sometimes Usually Task(s) 5. Is the worker exposed to temperatures more than 90ºF?   4 ________ Page 11 of 18

40. NOTE: Industrial Hygiene’s areas of expertise. Need to Contact Industrial Hygiene No Sometimes UsuallyTask(s) 4. Is a respirator worn?  H ________ 5. Is the worker exposed to temperatures more than 90ºF?   4 ________ NOTE: If Question 4 or 5 is marked H or 4, refer to Industrial Hygiene Page 11 of 18 H

41. 2nd Level Analysis Tools Question2nd Level Analysis Tools Supplemental Analysis Energy Expenditure 1Walk > 40' + carry > 5#Energy Expenditure ProgramForce Gauge 2Climb stepsEnergy Expenditure Program 3Bend below kneesEnergy Expenditure Program 4Respirator use(Refer to Industrial Hygiene) 5Exposed to > 90F(Refer to Industrial Hygiene) New No.

42. Task Definitions

43. Predicting Energy Expenditure  Energy is measured in kcal/min.  Actual energy expenditure requires a real person.  Predicted energy expenditure requires knowledge of job elements.

44. Energy Expenditure: Major Areas of Concern  Lifting  Lowering  Walking  Carrying  Climbing

45. Garg’s Energy Model  Basis for the software program  Metabolic cost due to maintenance of body posture (E p )  Metabolic cost due to work (E w )  Total metabolic cost = E p + E w  Work Cycle = Time  Average metabolic rate for the job E p + E w E p + E w Time Time

46. Review of Snook Push/Carry Tool

47. Snook Tables Program NIOSH Lifting Program 3D SSPP Energy Expenditure Program Analysis Decision UAW-GM RFC2 Upper Extremity Section Energy Expenditure Section Manual Lifting Section Posture Section

48. Trigger Question

49. Basis of Snook Tables  Psychophysical research: –measure of perceived exertion: determine design criteria for pushing, pulling, carrying –identify workloads acceptable to workers  Realistic simulation of industrial work  Results: –are consistent –can be reproduced

50. Study Design  Subject controls amount of weight/force  Subject instructed to maintain a maximum workload without becoming: –Excessively tired –Overheated –Out-of-breath  Study repeated hundreds or thousands of times for male and female subjects.  Variables (height, frequency and duration) are pre-determined for carry/push/pull tasks

51. Why Snook Tables?  Realistic simulation of industrial work  Results: –are consistent –can be reproduced

52. Use of Snook Tables 5 Types:  Lift  Lower  Push  Pull  Carry Normally covered by MMH

53. Pushing/Pulling Tables  Male and female capacity  Indicate: –initial force (to get object in motion) –sustained force (to keep object in motion)

54. Pushing/Pulling Tables  Inputs required for determining forces: –handle height (knee, waist, shoulder) –push/pull distance –push/pull frequency –% of population capable

55. Carry Tables  Male and female capacity  Inputs required to determine weight: –carry height (elbow, knuckle) –carry distance –carry frequency –% of population capable

56. Actual Snook Table

57. Snook: Main Page

58. Snook: Push Male

59. Decision-Making Hierarchy  Use the Female 75% accommodated for most analyses.  Use the closest value.  If between two options, err on the side of the worker.  Analyze multiple scenarios.  Use common sense.