Ergonomics

Ergonomic related dysfunctions seen in human body. Various jobs and its disorders due to constant improper position of human body

1. Ergonomics
BY:Radhika Chintamani

2. Contents
•Introduction and definitions
•History of ergonomic
•Job analysis
•Making the recommendations
•Return-to-work transition
•Work conditioning and work hardening
•Job simulation
•Occupation specific ergonomics
•References

3. Ergonomics
Greek, Ergon- work, Nomos- laws
Laws of work

4. That branch of science and technology that includes what is
known and theorized about human behavioural and biological
characteristics that can be validly applied to the specification,
design, evaluation, operation and maintenance of products and
systems to enhance safe, effective and satisfying use by
individuals, groups and organizations.
Wilson J R(Christensen et al. 1988)

5. Ergonomics (or human factors) is the scientific discipline
concerned with understanding of the interactions among humans
and other elements of a system and the profession that applies
theory, principles, data and methods to design, in order to
optimize human well-being and overall system performance.
International Ergonomics Association(IEA)

6. History of ergonomics
4 levels of technology by focusing on the contributions made by
humans and machines to the total system, in terms of power and control.
•Lowest level: human supplies both power and control
•Second level: machine supplies primary power, while the human
retains control
•Third level: machine supplies both power and information, but human
still controls and operation
•Highest level: machine supplies power, control and information and
human.

7. •Fifth level: machine provides power, control and ability to
monitor itself and make intelligent decisions in the complete
absence of human intervention.

8. Basic Principles
Biomechanical Principles
-Joints must be in a neutral position
-Keep the work close to the body
-Avoid bending forward
-A twisted trunk strains the back
-Sudden movements and forces produce peak stresses
-Alternate postures as well as movements
-Limit the duration of any continuous muscular effort
-Prevent muscular exhaustion
-More frequent short breaks

9. Anthropometrics principles
-Take account of differences in body size
-Use the anthropometric tables appropriate for specific
populations
Physiological Principles
-Limit the energy expenditure in a task
-Rest is necessary after heavy tasks

10. •Primary and secondary school teachers appear to be more prone
to neck, shoulder and back pain.
Patience N E and Derek R S. A systematic review of musculoskeletal disorders among school
teachers. BMC Musculoskeletal Disorders 2011, 12:260.
•The regions of symptoms were neck (75.74%), wrist/hand
(73.13%),
lower back (72.01%), shoulder (69.4%) in dentists
Vijaya K K, Senthil P K, Mohan R B. Prevalence of work related musculoskeletal complaints
‑
among dentists in India: A national cross sectional survey. Indian Journal of Dental Research. 2013; 24(4):
‑
428-38.

11. •The period prevalence of musculoskeletal complaints was
highest for the low back, the shoulders, the knees and the
neck in professional divers of Sweden.
Hedberg G E. The period prevalence of musculoskeletal complaints among Swedish professional
drivers. Scandinavian Journal of social Medicine. 1988; 16(1):5-13

12. Job Analysis
“manifold is the harvest of diseases reaped by certain workers from the
crafts and trades that they pursue. All the profit that they get is injury
to their health, that stems mostly, I think from two causes. The first and
most potent is the harmful character of the materials that they handle,
noxious vapors and very fine particles, inimical to human beings,
inducing specific diseases. As a second cause I assign certain violent
and irregular motions and unnatural postures of the body, by reason of
which the natural structure of the living machine is so impaired that
serious diseases gradually develop…”
Bernardinoo Ramzazinni,
De Morbis Artificum
About Diseases of Workers, 1700

13. Carpal tunnel syndrome, repetitive motion problems, cervical strains, low
back pain and degenerative disc disease.
It is not enough to treat these problems in the clinic.
Job site treatment- mismatch between the worker’s capabilities and
workplace demands.

14. Job Analysis
-matching workers’ functional capacities with job
-Making hiring and job placement decisions
-Identifying and correcting risk exposure
-Determining Work conditioning or Work hardening goals
-Designing a modified job to ensure a safer return to work

15. •The term job analysis refers to total analysis continuum of which Job
Demands Analysis (JDA), Task Analysis (TA) and Ergonomic
Evaluation (EE) are subsets.

16. Analysis Continuum
Job description
A written or verbal description
of the functions of the job
Job demand analysis
A checklist or itemization of the physical
demands of the job in general
Task analysis
A detailed inventory of the frequency, duration and forces
required to meet the major demands of the job
Ergonomic evaluation
A mathematical analysis of the physical aspects of the job which
might be considered hazardous based on the above analysis

17. Purposes and Applications
-To ensure non-discrimination when conducting pre-placement
medicals, the specific demands of a job can be compared
objectively and systematically to a diagnosed medical condition
ensuring appropriate placement
-Job demands can be used to quantify strength, endurance, range
of motion and other physical factors required by the job

18. Worker/job match
Job match
The person
(ability to do it)
Functional capacity
assessment
Experience, work history,
interests, aptitudes,
abilities, skills, education
Training
Aids to
accommodate
Job description:
education, skills
Job demand
analysis
The job
(work to do)

19. Applications
-Rehabilitation requirements
-Job modification
-Reasonable accommodation
-Training and injury prevention programs
-Job and tool design and redesign

20. Making the recommendations
Job Modifications
1.Physical Accommodations
-Height of a desk
-Adjustable desk
-Ergonomically designed chairs
-Changing the distance
-Providing a motorized scooter
-Arm or wrist support
-Rearranging office furniture
-Materials handled can be bundled in smaller weights or more manageable
box sizes

21. 2. Environmental Adaptations
-Temperatures
-Loud noises can be diminished
3. Work Site Modifications
-Ramps and easily opened doors
-Elevators
-Restrooms with grab bars, large enough for wheelchairs
-Flooring

22. 4. Job Restructuring
-Unnecessary task procedures can be identified
-Reassigning tasks
5. Work Activities Modification
-Altering arrival and departure times to assist with
transportation needs
-Dividing rest and lunch breaks into more frequent, shorter
rest periods

23. Return-to-work transition
- Transitional Modified Job
-The Transition Process:
1.Prepare job and task demand analysis
2.Determine worker’s functional capacity
3.Determine tasks which may be within the worker’s capabilities
4.If worker is being assigned a transitional job, the Therapist typically
offers modified work in form of progression by hours and by tasks.
5.Identify how tasks of job which employee is unable to do currently,
will be addressed.

24. 6.Prepare new Job Demand analysis to describe work assignment
7.Transitional job- discuss modified work and progressed or stepped hours with the
worker
8.Advice the worker that copy of Task Analysis will be sent to their physician
9.Prepare a cover letter to the physician explaining organization’s work program
and commitment to rehabilitation. Transitional work- progressed/stepped
approach and demands of the transitional “modified” work that has been offered
10.Copy demands analysis and cover letter and send to insurance carrier involved
11.Keep all pertinent information in a disability management file for each person.

25. Work conditioning and work hardening
•Work conditioning is a work related, intensive, goal-oriented
treatment program specifically designed to restore an
individual’s systematic, neuromusculoskeletal (strength,
endurance, movement, flexibility and motor control), and
cardiopulmonary functions. The objective of the work
conditioning program is to restore the client’s physical capacity
and function so the client can return to work.

26. •Work hardening is a highly structured, goal-oriented,
individualized treatment program designed to return the
person to work. Work hardening programs, which are
interdisciplinary in nature, use real or simulated work
activities designed to restore physical, behavioural and
vocational functions. Work hardening addresses the issues
of productivity, safety, physical tolerance and worker
behaviours.

27. Rehabilitation systems, the individual components of which have
evolved to address specific aspects of the return to work process.
Increased success rates, accelerated time frames, increased
restored function and productivity, reduced re-injury and lower
costs.

28. Medically healed and prepared to return to work at full job
functions
•Physical strength
•Physiological resources
•Psychological equilibrium
•Healed- vulnerable to re-injury

29. Measures beyond healing required in order to accomplish a safe
and successful return to full productivity
•Physical strength
•Injury or illness-induced physiological and chemical changes
that impact energy levels and endurance must be reserved
•Capability in strength and endurance depleted by inactivity
must be restored

30. Benefits
•Clients- presented with clear realistic goals and are imbued
with motivation and confidence required to success
•Physicians- patients in effective programs and their return to
work releases can be based on comparison of Functional
assessment results and Jab Analysis, not their own call
•Employers- treatment approach focuses on restoring
productivity to worker, hence, the company, while also
lowering the risk of re-injury

31. •Vocational rehabilitation consultant, insurance representative,
workers’ cooperation case worker and other involved parties-
because they have a formal system which facilitates gaining
client cooperation, monitoring progress, making midcourse
adjustments and reaching more intelligent case closure
•Attorney- due to client
•Therapists- work retraining is a conduit to additional services,
also generates referrals from family members and friends of
employees.

32. Return-to-work Requirements
Physical capabilities
Strength. Endurance
Flexibility. Mobility
Support structure
Systematic approach
Preventive education
Workers’ compensation understanding
Health care . Knowledge of options
Honesty and trust. Well defined goals
Self management skills
Pacing. Coping skills
Co-workers interaction
Employee/employer communication
Pain management. Work habits.
Confidence/motivation

33. Elements of Work Retraining are
•Restore dynamic function to the highest achievable levels within the
reimbursable time frames and treatment procedures.
•Address the needs of the whole person- the psychological needs as well
as the physiological
•Organize treatment professionals and other stakeholders and
participants into a team which includes the client as the centre of the
team’s focus
•Involve client in understanding the current needs, goal setting, planning,
monitoring progress and making adjustments as progress proceeds.

34. Assessments

35. Flexibility and Mobility
•Improve circulation reduce neuromuscular inhibition, provide carryover
into functional activities and improve confidence in the ability to safely
move into postures
•Level 1 flexibility/mobility exercises
–Cervical ROM and stretch exercise: flexion, extension, retraction, lateral flexion
and upper trapezius stretch
–Shoulder: external and internal rotation, horizontal abduction and adduction,
extension, Codman’s pendulum and caudal glide
–Back: pelvic tilt, single knee to chest stretch, prone on elbows, standing foot on
chair low back stretch and prone back extension.
–Hip, knee: inner thigh and groin stretch, seated or supine hamstring stretch,
quadriceps stretch, hip flexor stretch and piriformis stretch

36. Strengthening
•Develop strength in select areas of the body
•Work through specific areas of deficits
•Support general improvement within program
•Improve clients ability to perform job simulation activities
•Strengthen body parts to accommodate mechanical stresses
that will eventually be placed on the body
•Increased localized strength for maintaining static postures
necessary for the job.

37. Level 1 strengthening exercises
•Cervical: AROM, isometrics and stabilization exercises
•Shoulder: AROM, PRE’s and isokinetic exercises involving
external and internal and internal rotators, supraspinatus, flexion,
abduction, biceps, triceps and rhomboids
•Back: ROM, stabilization and equipment-specific back extensions,
gluteals and abdominals
•Hip, knee: quariceps, hamstrings, abductors, adductors,
gastrocnemius and gluteals

38. Job simulation
Work stations that simulate dynamic job functions
should be matched to the individual based on:
1.Job classification
2.Postural treatment needs
3.Body part injured

39. Functional circuit
•Based on SAID principle.
•Structured to require postures and movements that are in
need to rehabilitating and strengthening
•Direct observation
•Indirect observation

40. Direct observation
-Activities included in a standard FCA such as kneeling,
crawling, bending, stooping, squatting, reaching and grasping
-Eye-had coordination
-Mobility
-Reports and behaviours
-Hearing and seeing

41. Indirect observation
-Pacing
-Sequencing
-Ability to follow multiple instructions
-Safety practices
-Partner and group responsiveness
-Guarding
-Segmental abilities and limitations
-Motivation and cooperation
-Consistency

42. Education
•Primary topics
-Back
-Upper Extremity
-Stress Management
•Secondary topics

50. Desk job

51. Overhead work

52. Below waist

53. Teachers

54. Drivers

56. References
•Glenda L K. Industrial therapy. Mosby, USA. 2002.
•Patience N E and Derek R S. A systematic review of musculoskeletal disorders
among school teachers. BMC Musculoskeletal Disorders 2011, 12:260.
•Vijaya K K, Senthil P K, Mohan R B. Prevalence of work related musculoskeletal
‑
complaints
among dentists in India: A national cross sectional survey. Indian Journal of
‑
Dental Research. 2013; 24(4): 428-38.
•Hedberg G E. The period prevalence of musculoskeletal complaints among
Swedish professional drivers. Scandinavian Journal of social Medicine. 1988;
16(1):5-13

57. Thank you!