ERGONOMY Dr Majid Golabadi People Are Different People

ERGONOMY Dr Majid Golabadi

People Are Different

People Have Physical Limitations

People Have Emotional Limitations

Terminology ERGO = WORK NOMOUS = LAW

NIOSH: The science of fitting workplace conditions and job demands to the capabilities of the working population “fitting the job to the worker”

A Model Framework for Assessment of Medical Fitness for Work Person • Relevant medical history • Functional capacity (physical/psychological) Risks Fitness for Work • Employee • Employer • Colleagues • 3 rd parties (customers/service users/public) Job • Demands/requirements • Safety critical work • Hours, travel etc

Ergonomics a Multidisciplinary Science OHS Phisiology Anatomy Biomecanics Design Management Ergonomics Engineering Environmental Science Psycology Computer Science Toxicology

The function of specialists in ergonomics is to redesign or improve the workplace, workstations, tools, equipment, procedures of workers and work organization so as to limit fatigue, discomfort, and injuries

Payback period for ergonomic interventions 1 Year

Job redesign outcome 1 - Reducing risk factors for common Musculoskeletal Disorders 2 - Reduction in Acute Injuries

Statistics suggest that more than 30% of all occupational injuries are musculoskeletal injuries

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These painful and often disabling injuries generally develop gradually over weeks, months, and years.

MSDs can cause a number of conditions, including pain, numbness, tingling, stiff joints, difficulty moving, muscle loss, and sometimes paralysis. Frequently, workers must lose time from work to recover; some never regain full health.

MSDs usually result from exposure to multiple risk factors that can cause or exacerbate the disorders, not from a single event or trauma such as a fall, collision, or entanglement

What causes work-related MSDs? Work-related MSDs occur when the physical capabilities of the worker do not match the physical requirements of the job. Prolonged exposure to ergonomic risk factors can cause damage a worker’s body and lead to MSDs.

Ergonomic Risk Factors

The physical stressors or risk factors that are associated with Work related Musculoskeletal Disorders are: • Sustained awkward postures • Static/Sustained Posture • Sustained or high forces • Rapid, repeated motions • Contact stress • Vibration • Cold environment

Awkward Posture Deviations from neutral positions. The greater the degree of deviation, the higher the risk.

THE HEAD AND NECK NEUTRAL FLEXION EXTENSION

THE TORSO AND BACK NEUTRAL FLEXED TORSO AND BACK EXTENDED TORSO AND BACK

THE ELBOW AND SHOULDER NEUTRAL 90 -110’ ELBOW FLEXION <90’ ELBOW EXTENSION >110’

THE HAND WRIST NEUTRAL RADIAL DEVIATION EXTENSION ULNAR DEVIATION FLEXION

Static/Sustained Posture When a worker must maintain an unsupported position for an extended period of time.

The constricted blood flow reduces the supply of nutrients to the muscles and the removal of acids and other waste products away from the tissues. Reduced blood flow also slows down delivery of oxygen to the muscles

End Range Posture Refers to moving a joint as far as it will go or close to its maximum. Stress is on the muscles, tendons and ligaments as they are stretched to end range.

Improvements

Forceful Exertions

Forceful Exertions The amount of work the joints, muscles, and tendons must do to perform the task. The higher the force, the more risk of fatigue, loss of strength, and injury to muscles, tendons and joints.

Repetition Refers to a task or series of motions performed over and over again with very little variation.

Repetitive motion disorders (RMDs) a family of muscular conditions that result from repeated motions performed in the course of normal work or daily activities

The disorders are characterized by pain, tingling, numbness, visible swelling or redness of the affected area, and the loss of flexibility and strength Over time, RMDs can cause temporary or permanent damage to the soft tissues in the body such as the muscles, nerves, tendons, and ligaments - and compression of nerves or tissue.

Tendinitis Bursitis

Contact Stress An outside force coming in contact with the soft or unprotected part of the employee’s body. The amount of damage is dependent on the sensitivity of the exposed body part.

Vibration

Vibration Damage to blood vessels Increased muscle fatigue Damage to spine Vision problems Headaches Insomnia

Vibration Reduce the vibration/modify speed Equipment maintenance Vehicle suspension systems Reduced exposure Rest breaks Adequate padding/absorption system Education

Environmental

Environmental Factors Temperature Noise Lighting Air Quality

Hazard Prevention and Control Design of the Work Station Design of the Work Task Design of the Tools/Equipment

WORKSTATION DESIGN PRINCIPLES Reduce Sustained Awkward Postures Reduce Contact Stress Design Work Based on Anthropometric Data Logically Locate Controls and Displays Proper Design of Chairs Avoid Static Body Positions: Task Variation and Exercises Proper Placement of Monitor & Documents