Summary Ergonomics

ERGONOMICS IN OCCUPATIONAL THERAPY
What is Ergonomics?
 The study of work performance → emphasis on keeping workers safe and productive
o Originated in work
o Also applicable to other areas of OT (play, leisure, learning, PCL, social
interaction)
o Aka human factors
 Multidisciplinary field of study
o Developed from interests of engineers, psychologists, & health professionals
 There are now degrees in Ergonomics / human factors up to doctoral level
 But many professionals still use ergonomics in their practice, including OTs
What is the purpose of Ergonomics?
 Optimization of relationship between environment and person
 When there are no ergonomic problems, user is unaware of design issues and can
focus on task
What is the role of OT in Ergonomics?
 Three main areas of practice:
o Workplace analysis for prevention of work-related musculoskeletal injuries
o Tool and workplace design for persons with disabilities (including universal
design)
o Development of ergonomics training programs through consultation and
participation
How does client-centered practice relate to ergonomics?
 Inclusion of persons with disabilities in design and decision making
o Advocating for client needs
o Recognising clients’ knowledge and experience
 Important to collaborate with the individuals involved when applying ergonomics in
institutions

 What are the principles of client-centered practice relating to ergonomics?
o Enacting participation and partnering throughout the process
o Respecting and enabling worker and organization choices, needs, and
knowledge
o Focusing on Person-Environment-Occupation (PEO) relationships in practice
context
o Addressing physical comfort and emotional support needs of clients
o Fostering open and transparent communications and knowledge exchange
o Establishing a shared vision for ergonomic management
o Establishing shared and realistic goals among work parties
o Creating opportunities and engage workplace parties in problem solving and
decision making
o Ensuring a flexible and individualized occupational therapy approach

,What is Anthropometry?
 Science of measurement of human body
 What are the universal factors that affect human size & shape?
o Gender
o Ethnicity
o Age
o Occupation
 Disability is often overlooked in environmental and product design
What is the application of anthropometry?
 What is Reach?
o a sphere around worker that can be touched at all points without moving the
body from the starting point
 If standing with arms unobstructed:
 Shoulder will be the axis / centre of sphere
 Length of arm is the radius
 If arms are obstructed (i.e., working at desk)
 Elbow is the axis / centre of sphere
 Forearm to hand distance is the radius

o What is Vertical Reach?
 area that person can reach from top to bottom
 represented by an arc
 Determine:
 Posture at rest: sitting/standing; elbow & shoulder
flexed/extended?
 Occasional extended reach is the extra area person can reach when
leaning forward
 E.g., Working on vertical control panels,
reaching objects off high shelves

o What is Horizontal Reach?
 area person can reach from front to back
 defined by the counter, desk, or tabletop
 Four zones:
 Normal work distance:
→ arc made by forearm when the body is close to the table
and elbow close to the body.
→ Most precision work is done in this area.
 Extended working distance:
→ Area made by the arc of the arm when the elbow is straight.
→ Frequently used tools, supplies and heavy objects should
be stored in this area.
 Maximum work distance:
→ arc made when the trunk leans forward
→ Infrequently used tools and supplies should be stored here.
 Most efficient workspace:
→ 250mm square directly in front of the worker, about a hand’s
span from the edge of the table
→ Most people prefer to work in this zone.
o What is Visual Reach?

,  area worker can comfortably see from static position
 Most relaxed area is 10 to 15 degrees below horizontal
 Place screens and monitors
 Eye can comfortably see 15 degrees above and
below this angle
 Comfortable reading distance is 400mm to 700mm
from the eye

 What is Clearance?
o Leg room
o Seated work should allow space for legs to move and change position
o Drawers under work surfaces and thick counters reduce leg room

 What are the principles of Ergonomic Posture?
o Both Standing and sitting have advantages
 The best position is as close to neutral as possible – least strain on
the body
 Standing:
o head aligned upright over trunk
o centre of gravity over hips
o knees slightly bent
o arms in a relaxed position
 Sitting:
o Leaning back slightly in the chair at 105 degrees
(slightly reclined)
o knees and ankles at 90 degrees.
 Static postures can lead to development of musculoskeletal disorders.
→ Postures should be changed frequently
 Forward flexion of the neck should be avoided. Rather lift the work
surface.
 Upper arms should be close to the body, and lifting arms overhead
should be avoided.
 Body parts should be in neutral position as far as possible – avoid
twisting and asymmetry.
 Avoid extreme ranges of motion and awkward postures.
 Back support should always be provided.
 Place body parts in positions of greatest strength

 What is Precision and Stength?
o Precision work (e.g., electronics, jewellery, sewing)
 closer to the eyes
 close to the body
 arms or hands should be supported while working
 should be done at 50mm to 100mm above elbow height
o Light work (e.g., typing, writing)
 done at just below elbow height
o Work requiring strength (e.g., kneading dough, hammering)
 150 to 400mm lower than elbow height