Intro to Occupational Mechanics Flashcards
Ergo
work
Nomos or Nomoi
natural laws
Ergonomics
Management and labor recognize that injury reduced performance reflect a mismatch between the worker, the task, and the environment
Mistmatch does what
predisposes to injury
Individual
Body size and shape (anthropometrics)
Fitness level/injury history
Off-work activities
Psychological status, motivation
Environment
Physical layout
Psychological demands
Top occupations
Nursing aids, orderlies, and attendants
Laborers
Janitors and cleaners
Truck drivers - heavy and tractor trailor
Registered nurses
Truck driver - light or delivery services
Top causes of injury
Overexertion
Repetitive motion
Types of injuries from most to least common
Sprain and strain Contusions Lacerations Fractures Burn Cumulative trauma Tendonitis ChemBurns Amputations
Ergonomics - psychologists investigate
mental function and the workplace
Human factors, cognitive factors
Ergonomics - exercise physiologists evaluate
metabolic, respiratory and cardiovascular effects of prolonged, strenuous activities in industry
Work physiology
Occupational biomechanics
apply laws of physics and engineering concepts to describe motion undergone by various body segments
Biomechanics is the science concerned with
the mechanical behavior of the NMS and component tissues when physical tasks are performed
Chafflin/Anderson/Vardaxis definition of occupational biomechanics
Study of physical interaction of workers with their tools, machines, and materials aiming to idtentify risk of injury, control stresses and energy expenditure, and improve worker performance, efficiency, and comfort
Who uses occupational biomechanics
Engineers
Safety managers
Allied health providers
Kinematics
time and space
Displacement
Velocity
Acceleration
Kinetics
Force (torque) and energy
F=ma
Occupational biomechanics complements___
psychological and physiological knowledge
Occupational biomechanics considers interaction of
worker, task, and workplace
Occupational biomechanics focus is
mechanical stress on the body
Mechanical stress =
force/area
Epidemiological support of occupational biomechanics
Health and quality of life are greatly reduced for many because of musculoskeletal disorders
We want to maximize safety and productivity - in order to do that we need to
min fatigue and overexertion Improve quality and quantity of output Min time lost and cost of injury Min absenteeism and turnover BUT important to fit the job of the worker
Social/legal support for occupational biomechanics
Hiring cannot discriminate on basis of Age Race Gender Disability BUT jobs must not provide undue risk for injury
OSHA act of 1970 - Employers are to provide employers with
A safe working environment Safe tools Knowledge of hazards Competent fellow employees and managers Safety rules
Implementing a program - attitude
Employee - self help
Employer - investment
Safety must be accpeted as
Legally necessary
Economically advantageous
Ethically imperative
Event - sudden force
Trauma type =
Impact
Event - sudden force
Trauma type = impact
Typical medical outcomes =
Contusion (bruise) Laceration (cuts) Sprain (ligament) Fracture (bone) Subluxation/dislocation (joint) Concussion (brain)
Event - volitional activity
Trauma type =
Overexertion
Event - volitional activity
Trauma type = overexertion
Typical medical outcome
Muscle strain Tendonitis Tenosynovitis Myofascial disorders Nerve entrapment Low back pain
Event - repeated motion
Trauma type
Overexertion, overuse injury
Occupational risk factors - principle
FIT
Frequency (repetition)
Intensity (force exerted)
Time (duration of loading)
Anthropometry
deals with the measure of size, mass, shape and inertial properties of the human body segments
Biomechanical models
facilitate predication of a body’s response and the design of the work space interface
Body segment - links
Link length can be defined as
the distance between projected centers
Injury risk (lives) depends on
the validity of the model
The mass of the body segments adds
additional stresses to the body beyond those exerted by external forces
Resistance to acceleration
These weight related stresses can be
of considerable magnitude in certain postures
a force
Insufficient to know only the mass (weight) of a body segment to perform an analysis - must locate
the center of mass fo reach segment
Need to know
Mass center location in segment
% TBM (weight)
Link length
When a segment translates and/or rotates during dynamic activities what needs to be considered
The inertial properties
Moment of inertia is not only mass, but
mass distribution
Greater the moment of inertia, the
greater the inertial load
and the greater the joint stress
Anthropometric data defines the
Reach and space requirements of a specified population or equipment user
Important consideration for workplace design
Workplace analysis - tables of what kind of data
percentiles
90%
Summary -
Knowledge of anthropometry is important
Anthropometrics is basis of models
Design must accomodate 5th to 95th percentile