Ergonomics

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Ergonomics
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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.

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• 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

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• 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 .

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• 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

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• 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.

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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

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• 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

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• 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

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• 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

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• 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)

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environments
Human
Machine
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• 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

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• 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

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Pull force
Push force
Body wt
Body wt
Rectus force
Erector force
Disk load
Disk load
Erector force
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How to carry objects with maximum efficiency and
least harms
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Choosing the seat
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Choosing the objects hand design
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Correct
Incorrect
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Thanks