2. EVALUATION OF INTER- RATER RELIABILITY FOR MOVEMENT AND POSTURE OBSERVATIONS OF WORKERS IN AN AUDIO COMPACT CASSETTE PLANT

3. The incidence of work-related musculoskeletal disorders has tripled in the US during the past decade. 11,586 cases who had occupational injuries from lifting heavy objects (1 death case, 19 cases as permanent partial disability, 1,432 cases as temporary disabilities > 3 days and 10,134 cases as temporary disability <= 3days ) the Social Security Office, Ministry of Labour and Social Welfare, Thailand(1998)

4. Laboratory and epidermiologic studies have identified association between various work-related musculoskeletal disorders and exposure to highly repetitious or static work, work requiring high force, awkward postures, localized contact pressure, vibration and cold

5. Ergonomics is defined as the study of the interaction between workers and the equipments being used and the environments in which they function. Well accepted that manual handling jobs pose the high risk of injuries. Posture can be a major determinant of the amount of force required to perform a task.

6. Such as working with arms overhead has been linked to rotator cuff tendenitis, pinch gripping with the carpal tunnel syndrome. The application of this knowledge to the workplace is essential to order to enhance productivity and to increase the social responsibility of the firm.

7. OBJECTIVE This study examines the inter-rater reliability of an observational ergonomic exposure method to assess the movement and posture required by work tasks.

8. MATERIALS AND METHODS Subjects Four well trained observers(A,B,C,D) independently evaluated the task of 23 workers in an audio compact cassette plant. The plant is in an industrial complex in the vicinity of Bangkok. All were observed in the plant in April 2000.

9. MATERIALS AND METHODS Movement and posture check list were adapted to be proper with the jobs at that field. All the jobs were observed in the area of molding department, audio assembly area and audio package department.( all workers didn’t be told before)

10. MATERIALS AND METHODS Instrument The ergonomics exposure data were recorded on a onsite observation check list. each job observed, information include plant, department, operation number and day of evaluation. The picture 1-28 for evaluation of movement and work posture (17 movements and 11 postures)

11. The picture and detail of the adapted on site observation check list Picture 1. wrist flexion Picture 2. wrist extension Picture 3.Medial flexion of wrist Picture 4.ulna deviation Picture 5.close round pinch Picture 6.close elongated pinch Picture 7.handling

13. Picture 8. gripping Picture 9. shoulder extension Picture 10.shoulder flexion Picture 11.elbow flexion Picture 12. shoulder rotation Picture 13. Pronation Picture 14. Supination Picture 15.neck flexion Picture 16.neck extension Picture 17.lateral rotation of neck

15. Topic of Evaluation 1.Repetitions as very often - twice or more in one minute often- once for each period of 1- 3 minutes occational- once in more than 3 minutes

16. Topic of Evaluation 2. speed as Very fast - close to the maximum speed that can be repeatedly performed by the worker for a given manufacturing operation. Moderate- is the speed that most resembles natural body movements Slow- is a speed that is notoriously lower than the moderate

17. Topic of Evaluation 3.Forceful exertion Much - similar to the maximum value that can be maintained during one half of a minute Moderate- similar to the maximum that can be maintained during a period lasting from 1 to 3 minutes Little- any force that can be maintained for more than 3 minutes

18. The pictures 18- 28 of onsite observation check list were shown as working postures Picture 18 standing Picture 19standing with back bending Picture 20awkward Picture 21standing with raising arm above shoulder Picture 22standing with raising arm below shoulder Picture 23 kneeling

19. The pictures 18- 28 of onsite observation check list were shown as working postures Picture 24sitting with back straight Picture 25sitting with back bending Picture 26squatting Picture 27sitting with raising arm above shoulder Picture 28squatting with raising arm above shoulder

21. Topic of Evaluation 1. Posture time ( accumulated time during daily journey) : - Between 0 and 1 hour - Between 1 and 3 hour - More than 3 hours

22. Topic of Evaluation 2. Forceful Exertion : Much - similar to the maximum value that can be maintained during one half of a minute Moderate- similar to the maximum that can be maintained during a period lasting from 1 to 3 minutes Little- any force that can be maintained for more than 3 minutes

23. Topic of Evaluation 3. Kind of force applied : - Pushing - Pulling - Twisting the body

24. Each task was observed for each cycle at least 3 minute and did as watching all tasks in each cycle at least once time before beginning to count and record specific movements and postures

25. Data analysis methods Inter-rater agreement on the frequency per cycle, speed of motion and forceful exertion of each of the the 17 movements. Inter-rater agreement on the accumulated time, forceful exertion and kind of force applied of each of the 11 postures. All using statistical approaches : proportion of agreement and kappa (SPSS 9.0 for Windows software package)

26. Data analysis methods 92 observation check lists were completed by all 4 raters ( 23 check lists for each rater ) conduct analysis in the pair of raters, rater A and rater B, rater A and rater C and rater A and rater D.(Rater A is a trainer of all other raters for using this adapted observation check list)

27. RESULTS percent agreement on categorized repetition of movement counts, speed of movement counts, exerted force of movement counts( picture 1-17) of all pairs of raters( A,B and A,C and A,D). range from 57% ( from the issue of exerted force of close elongated pinch) to 100% for elbow flexion, neck flexion,lateral rotation and etc. Kappa statistics range from 0.24 – 1.00 ( fair to very good)

28. RESULTS Percent agreement on categorized accumulated time counts, exerted force counts, type of force on each posture ( picture 18-28 )counts of all pairs of raters( A,B and A,C and A,D) range from 83% for kneeling ( in the issue of accumulative time) to 100% for standing, awkward, standing with raising arm above shoulder and etc.. to 100%. Kappa statistics range from 0.36 – 1.00 ( fair to very good)

29. DISCUSSION AND CONCLUSION There are not much different between all observers in this assessment both in the part of movement and posture observation For this study, the adapted check list for movement and posture observation seem to be useful in real for the well trained observers

30. DISCUSSION AND CONCLUSION The tool of this study was developed to covered all details for evaluation of the ergonomic hazards by external parameters( tasks). To be the method of quickly screening a work population by simply recognition of the exposure risk for work related musculoskeletal disorders.

31. DISCUSSION AND CONCLUSION The debate over the best ergonomic exposure assessment methods Large populations at reasonable cost The versatility to estimate a variety of exposure factors The ability to represent the exposure over the appropriate length of time Reliability and validity of the method

32. DISCUSSION AND CONCLUSION Ergonomic exposure assessment is very important to identify problems and analyze jobs to determine health risks. As the part of ergonomic programs, effective assessment may lead to a reduction in medical costs, and significant improvement in workers’ attitudes.

33. DISCUSSION AND CONCLUSION However, the implementation of the proposed measures may face some problems such as the concerning of the worker, the organization’s management to develop preventive action to solve. It becomes essential to recognize and take the response in the issue of communication and information in the gathering step.

34. THANK YOU FOR YOUR ATTENTION