1 / 18

IE 327 Introduction to Work Design Dr. Andris Freivalds Class #4

IE 327 Introduction to Work Design Dr. Andris Freivalds Class #4. Ch. 4 – MUSCULOSKELETAL SYSTEM (and Work Design). MUSCLE STRUCTURE. Muscle and tendon Bundle of fibers Blood vessels Muscle fiber Myofibril Thick filament = myosin Thin filament = actin Sliding filament theory.

montana
Download Presentation

IE 327 Introduction to Work Design Dr. Andris Freivalds Class #4

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. IE 327 Introduction toWork Design Dr. Andris Freivalds Class #4 IE 327

  2. IE 327

  3. IE 327

  4. IE 327

  5. IE 327

  6. IE 327

  7. Ch. 4 – MUSCULOSKELETAL SYSTEM (and Work Design) IE 327

  8. MUSCLE STRUCTURE • Muscle and tendon • Bundle of fibers • Blood vessels • Muscle fiber • Myofibril • Thick filament = myosin • Thin filament = actin • Sliding filament theory IE 327

  9. FORCE-LENGTH RELATIONSHIP(Max strength at midrange) IE 327

  10. Achieve max muscle strength at midrange of motion • Where is midrange? • Relaxed posture • No muscle force • Weightless astronaut in space • Avoid extremes!! IE 327

  11. FORCE-VELOCITY RELATIONSHIP • Max muscle force with slow motion • Use momentum to assist work • Minimize fighting gravity IE 327

  12. OPTIMIZE HUMAN STRENGTH • Use optimum postures • Use large muscles for power • Avoid using back • Design tasks so that most can do! IE 327

  13. MUSCLE ENDURANCE • Static hold • Occlusion of blood flow • Rapid fatigue • Stay < 15% max • Short, frequent work-rest cycles • Dynamic work IE 327

  14. MOTOR UNIT RECRUITMENT • Use small muscles for precision • Use large muscles for power • Power vs. pinch grip!! IE 327

  15. CONTROL OF MOVEMENTS #1 • Pivot on elbow • Curved motions • Use both hands • Begin and end motion simultaneously • Move simultaneously to and from body • Use natural rhythms • Whole body = 17/min • Whole arm = 35/min • Forearm = 60/min IE 327

  16. CONTROL OF MOVEMENTS #2 • Use lowest classification of movement • Decrease difficulty of task • ↓ distance • ↑ target width IE 327

  17. MINIMIZE EYE MOTION(Within normal line of sight) IE 327

  18. KEY POINTS: • Design work according to human capabilities and limitations • For manipulative tasks: • Dynamic motion rather than static holds • Strength requirements < 15% max • Avoid extreme ranges of motion • Small muscles for speed and precision • Large muscles for strength IE 327

More Related