The document discusses job analysis techniques used in ergonomic assessments. It describes how job analysis identifies potential physical, psychosocial, and other risk factors that can contribute to musculoskeletal disorders. The process involves reviewing injury data, observing job tasks, interviewing employees, and measuring task demands. Interpreting the results breaks jobs into tasks to examine forces, postures, muscle activation frequencies, durations, and other factors. Relating demands to individual capacities helps determine if job modifications could reduce injury risks.

1. Job analysis
By: Radhika Chintamani
Ergonomics: It is the scientific discipline council with the understanding of interactions among
human and other elements of system, and the profession that applies theory, principles, data and
method to design in order to optimize human well being and overall system performance.
Occupation safety and Health act: [OSH Act 1970]: Main goal; to ensure that employers provide
employees with an environment free from recognized hazards, such as exposure to toxic
chemicals, excessive noise levels, mechanical dangers, heat or cold stress, or unsanitary
conditions.
Introduction to job analysis:
Ergonomic job analysis is the methodology used by engineers and safety professionals to
describe work activities for the purpose of comparing existing task demands to human
capabilities.
History and Background:
 Modern job analysis was primarily viewed as a tool for improving efficiency and
productivity.
 But in recent years job analysis fundamentals are applied in identifying the onset of
fatigue, musculoskeletal strain, overuse injury, etc; in order to effectively control,
eliminate or reduce the risk of injury to the work.
Job analysis techniques and its significance to occupational ergonomics:
 First- the benefits of well designed jobs include improved efficiency, safety, and
satisfaction of the employees.
 Second- the showing interest in ergonomics parallels the increasing impact of society’s
expectations about occupational health.
Fundamentals of Job analysis:
i. Identifying potential hazards.
ii. Preparing for field study.
iii. Conducting the flied study.
iv. Interpreting the results.
Indentifying potential hazards:
It’s the process of identifying the hazards arising from poor work design begins with two
activities;
1. Reviewing injury data:
Records are to identified in which jobs associated with a high rate of accidents and
injuries and absenteeism are noted down. Main reason for these are excessive work load
on the individuals and excessive turnover. These data can be collected by existing plant
records, and from survey of current employees.
Based on surveillance information, job must be selected for analysis based on the number
of injuries or complaints associated with the jobs, the severity of those injuries and
complaints and the number of workers affected by current job conditions.
2. Review procedure and Job activities:

2. It is the process of becoming familiar with the process of job activities that are performed
in each work area.
Information must be collected about the work area and type of job performed with several
other demographic details, by survey of the worksite.
Checklist may be used to identify potential risk factors that may be present at the
worksite and require further investigations like, as follows:
a. How many workers are employed in each job?
b. What are the characteristics of the workforce (eg. Gender, age, education level.)
c. Primary tasks involved in each job, constancy of the work, constant sitting or
standing during work, working hours.
d. Opportunity of workers to rotate to other jobs.
e. Salary of the employee, and type of pay system (eg. Per
hour/day/week/month/annual)
Preparing to conduct a job analysis:
1. Gather necessary equipments: most information needed to identify and evaluate
ergonomic hazards is collected through observation and direct measurement. Equipments
needs depend on nature of suspected hazards and the desired level of sophistication in the
measurement. Following items are useful in gathering the information:
a. Cameras and films: for recording workers posture and motions during job.
b. Tape measures and rulers: for measuring workstation dimensions and reach distances.
c. Force gauge and spring scales for measuring the force of exertion and weight of tools or
objects.
d. Stopwatches for measuring the duration of work activities, break etc.
e. Videotape can be valuable for documenting biomechanical stressors in the workplace.
Slow motions or real-time playback to accurately measure task durations or detect subtle
or rapid movements.
Various physiotherapy equipments used to analyze jobs and their uses are as follows:
Hand dynamometer Grip strength
Pinch dynamometer Pinch strength
Electromyography Rate and recruitment of number of muscle
fibers, and timing of recruitment
Gait analyzer To assess the gait of the subject
Plumb line Assessment of posture
Flex-e-curve To assess spinal curvature
Triaxial electrogoniometer 3 dimension trunk motion analysis
Accelerometers Describes acceleration of body systems.
Heart rate monitor ,
Oxygen uptake monitor
Metabolic load and physical stress
2. Identify strategy:

3. Primary objective of the field study is to collect sufficient information to allow the
analyst to completely describe the job as it is currently being performed (i.e. what the
worker is doing and how is he doing it). This can be done by collecting information about
the following points.
Sl.
No.
Physical Psychosocial Work-station Non-work related
Duration of employment
Duration of constant
sitting or standing (25%
of the day, 50% of the
day, 75%of the day or
greater)
Monotonous work(Y/N)
Physical tiredness at the
end of the day(Y/N)
Break during work.(Y/N)
Mental tiredness(Y/N)
Stressful lifestyle(Y/N)
Job variance(Y/N)
Work pressure(Y/N)
No support from
colleagues or
superiors(Y/N)
Getting annoyed by
others(Y/N)
Height of the
chair.
Height of the
keyboard. (If
comp)
Placement of
screen. (if comp)
Angle between
eyes and
computer screen.
(if comp)
Drive for long
distance to come
to office(Y/N)
Recreation
activities(Y/N)
Several studies have shown that, physical psychological, work related and non-work related
effect the individual’s job performance level. Hence all must be recorded while collecting the
data.
Evidence: A systemic review done by Craig et al, On risk factors for neck pain in computer
workers a club of 10 studies concluded that along with physical and workstation design,
emotional (such as stress or anxiety level, annoying behavior, support form collegues etc) and
environmental factors (such as long distant stay from office) play a role in enhancing or reducing
the work capacity of humans.
Conducting the field study:
This can be done by three processes,
i. Observe work processes: direct observation sometimes may help in collecting bulk of
information. In this process the person need not give any consent for recording. Here
the researcher becomes the active participant of the process. It is cost effective, but
sometimes time consuming.
ii. Interview supervisors and employees: questionnaire or schedules are given to the
supervisors and the employees. These question are directed towards their job and the
musculoskeletal or cardiovascular or mental health relating to their jobs. Also
satisfaction questions can be asked. At the end of the interview the scores are tallied
and level or percentage of risk is identified and noted down. Usually scales are used
in this step. Some of the scales used and their purpose are as follows;
Nordic neck pain scale Assess neck pain
SF-36 Health outcome questionnaire
Beck depression inventory Depression level during the work.

4. Job satisfaction questionnaire To assess the satisfaction level of the
employee
iii. Task measurements: observing the job also provides the analyst the opportunity to
make measurement at job site. Assessment of Workstation design is the best
technique to assess the work related hazards to health. Considering example of
computer workers,
Assessment of workstation design includes:
Placement of screen with respect to eyes.
Angle of neck flexion during working on computer
Angle of wrist extension during typing.
Placement of keyboard.
J sign
Duration of constant work of typing or looking into the screen of the computer.
Interpreting the Results:
Once data collection is completed, the first step in analyzing the result is to break each job into a
series of tasks and subtasks. The goal is to link excessive job demands to a specific aspect of the
job or work environment. Once jobs are broken down into tasks, the working methods,
workstation, and the tools and equipments required to perform the task can be examined to
determine if one or more of these elements contribute to the biomechanical stress of the task.
Each task must be examined in the flowing dimensions:
1. Forces required to perform the task: individual can produce certain amount of muscular
force to perform certain task. But on increasing the number of repetitions of the task and
also the muscular effort, indirectly there is onset of muscular fatigue, because of reduced
glucose content in the muscle. In addition high contrast force that create pressure over
one area of the body can inhibit nerve function and blood flow.
2. Posture assumed during the task: performing a task in a neutral posture requires less
effort on the musculoskeletal, and cardiovascular system to generate force produced to
maintain that posture. Certainly, it is a fact that on repetitive loading on the
musculoskeletal system at a particular posture, fatigue is seen, in response to the pain
induced by the constant posture individual certainly tries to attain a new posture avoiding
the painful posture. This abnormal posture attained by the individual to avoid pain may
create a problem for musculoskeletal system.
3. Frequency of muscle activation: muscles are set with a level of work, or rate of
activation. After this certain rate of activation muscle undergoes fatigue. Work duration
can have substantial effect on the likelihood of both localized and general fatigue. Fatigue
at the end of the day due to work can be broadly classified into physical tiredness at the
end of the day and mental tiredness at the end of the day.
4. Duration of work and recovery period: in some research articles it is significantly shown
that constancy of the work, working for longer duration, no break during work, no spouse

5. support and high work load on individual leads to decreased work performance. This may
be due to onset of musculoskeletal fatigue, mental tiredness at the end of the day, etc.
5. Exposure to vibration and cold: exposure of whole body vibration and has been
associated with increased back pain and upper extremity musculoskeletal disorders.
Exposure can be due to motor vehicles, powered hand tools, etc.
Cold temperatures can reduce the dexterity and sensibility of the hand, causing workers
to apply more grip force to tool handles and objects than vibration.
Information of other demographic details must be attained to accurately measure the factors
leading to the musculoskeletal disorders, like following:
a. Strength of data: if the force requirement of the task are known it may be helpful in
comparing the requirement in existing data to estimate the % of population for which that
particular job may be difficult. Computerized biomechanical model predicts individual’s
capacity of exerting static force in certain postures. It assess the capacity of force exertion
by assessing the group muscle strength and measuring the moment created at the joint.
b. Anthropometry: it is the physical non-invasive technique to measure the body size, and
composition. Anthropometric data on body size and range of joint motion can be used to
assess the appropriateness of workplace, equipment and produce designs relative to
workplace capacities for reach, grasp and clearance.
c. Physiological data: in activities such as repetitive lifting and load carrying, large muscle
groups perform submaximal, dynamic contractions. During these activities, a worker’s
endurance is primarily limited by the capacity of the oxygen transport and utilization
systems. In general, maximum aerobic capacity declines with age, increases with physical
fitness level, and is 13-30% lower for women compared to men.
d. Psychophysical data
e. Integrated model