2. Ergonomics

3. Introduction to ergonomics The term ergonomics is derived from two greek words : ergon meaning work and nomos meaning natural laws or rules So ergonomics means the laws of work The ergonomics aims to design techanical systems and tasks in such a way as to improve human safety, health, comfort and performance.

4. Ergonomics is the scientific study of people and their work It based on the study of human characteristics which included recognition of human capacities, abilities, habities and limitations. The limitation may be due to structure, function and behavior Then application of this knowledge to the work place design including design of tools, equipment and the total environment

5. The term man machine interaction in the human machine system (HMS) or work place is the understanding of the interaction between people and the machine they used. Ergonomics provides a good match between people and their environment which can result in better and more efficient human performance as well as the enhancement of health and safety.

6. The benefits of ergonomics Improving the quality of life Improving the quality of all human related activities Good ergonomics minimizes product costs and human errors and maximizes user satisfaction and health It makes the job safer by prevent injuries and illness makes the job easier by adjusting the job to the worker

7. Makes the job more pleasant by reducing physical and mental stress N.B physical stress to the body parts like ms, joints, bones….cause injuries which called repetitive strain injuries (RSIs) or cumulative trauma disorders (CTD) like carpal tunnel syndrome, bursitis, tenosynovitis and epicondylitis.

8. Ergonomics contributes to the prevention of injuries, disability and reinjure So It is therefore important in all stages 1- pre – injury stage called primary prevention which emphases should be considered on designing a safer human machine system via designing safe environment 2- in the post - injury stage. called secondary prevention. It contributes to the rehabilitation and management of trauma and disorders through effective comprehensive rehabilitation with the goal of preparing the individual to return to a productive lifestyle within a safe environment

9. 3 - in the post – rehabilitation stage called tertiary prevention. In this case emphasis is made on the design of effective programs to prevent reinjures and to ensure that the subject continues to 1- maintain functional capacities and 2- perform in safely in work

10. N.B good engineering, awareness and physical fitness are the three common factors in all of these stages of prevention The ergonomics is good in solving the problems associated with posture

11. Summary Ergonomics is highly relevant to preventive and occupational medicine, the management of musculoskeletal injuries and rehabilitation It help people to understanding their abilities and limitation and teaching them how to perform safely, effectively and comfortably within the environment

12. An ergonomist is a trained subject who has an experience in ergonomics and its application. An ergonomist can study human capabilities in relation to work demand in the human-machine systems(HMS) There are specific ergonomic standards which are applied in companies and industrial sectors. The most common one is the international standardization organization (ISO)

13. environments Machine Human

14. Pushing is preferred than pulling Pushing force is directed posterior on the spine so the bending moment is also posterior this moment is counteract by the abdominal ms which have the larger lever arm measured from the center of motion than the erector spinae ms so the required force is small

15. when the abdominal ms become tensed to resist the bending moment, the intra-abdominal pressure increase and the intra-thoracic increase this will decrease intra-vertebral disk pressure and decrease the load on the erector spinae ms

16. Push force Rectus force Body wt Erector force Pull force Erector force Body wt Disk l oad

17. How to carry objects with maximum efficiency and least harms

20. Choosing the seat

22. Choosing the object’s hand design

23. CorrectIncorrect