Lecture 6 - Work Physiology Flashcards
goals of work physiology
to ensure worker can persorm tasks efficiently and safely within the environment
- > to ensure efficiency
* to monitor energy expenditure and avoid access fatigue
- > to ensure safety
* do not push people beyond their physical limitations
human work capacity data can be divide into which 4 ares
- the epidemiological approach
- the physiological approach
- the biomechanics approach
- the psychophysical approach
epidemiological approach of human work capacity
based upo identifying the frequency distribution and possible control strategies of illness and injury for a given population
physiological approach to human work capacity
concerned with analyzing energy demands of the musculoskeletal system for work activities and reducing the energy expenditure of these work activities
biomechanical approach to human work capacity
- > concerned with determining forces exerted upon musculoskeletal system during work
- > predicts maximal, low and frequency capacity of individuals
psychophysical approach to human work capacity
concerned with human sensations associated with external stimuli
physical work capacity
energy requirements to do a task
the goal of ergonomics in the design of the physical component of jobs
to minimize unnecessary and possibly harmful stressors
are people who do physically demanding jobs healthier than desk workers
they’re more physically fit and healthier than there less active counterparts but they’re at a greater risk of fatal heart attack
how do you assess labour demands and workers capacities
- > metabolic function
- > cardiovascular function
- > respiratory function
- > strength and mobility assessments
metabolism
body takes in food and drink which contain chemically stored energy and converts them into mechanical energy
basal metabolic rate
minimum energy required to meet the metabolic demands of the body at rest
- > index of general level of activity of an individuals body metabolism determined by measuring the oxygen intake in the basal state (absolute rest but not asleep
resting metabolic rate
- > often difficult or impractical to achieve highly controlled conditions needed to measure basal metabolism
- > depending on the conditions, resting metabolism is around 10-15% higher than basal met.
work metabolism
increase in metabolism from resting to work
- > increase above resting levels represents the amount of energy needed to perform work
workload measurements
can be asses indirectly by recording the uptake of oxygen that is necessary for the oxidation of nutrients
- > energy consumption is measured in kilojoules
work energy consumption
(energy consumption while working) - (resting consumption or basal met.) = work Joules
classification of work demands (energy expenditure)
see slide 27
what to consider when designing heavy human work
- > whether it is necessary for hard physical labour to be done by humans vs machine
- > try to alleviate the workload as much as possible
- > provide rest breaks, encourage taking time off from work as needed
how do we measure work load
- > when energy requirements of work are low, measuring the workers O2 consumption provides little information
- > HR is easier to obtain and may be useful tool
- > Other measures (muscle activation - EMG; brain activities - EEG)
3 kings of worker judgement scales
*different ways to assess satisfaction w/work conditions is to ask workers for their opinions via:
- > ordinal
- > interval
- > ratio
ordinal judgement
arrange judgement in rank order, they also have statements of of “higher” or “lower”
interval judgement
require judgments set in sets that are equal distances from each other
ratio judgement
intervals scaled that are anchored by an absolute zero, therefore the numbered responses in ratio scales allow mathmatical calculations
Nordic Questionnaire
consists of 2 parts:
- > general information
- > focuses on region of the body
* uses a sketech of the body divided into 9 regions
* asks in one is experiencing musculoskeletal problems in those areas
factors that influence work performance
- > heat
- > cold
- > age
- > time of day (circadian rhythms)
steps for how to fit work to worker
- make work easy to do, avoid fatiguing postures and highly repetitive tasks
- Ask people for their opinions and judgments of the conditions of their work
- Strive to improve
craft brewery example discussed in class
- > purpose was to examine the different workstations for potential risks of injuries specifically related to repetitive motions and manual materials handling
- > usednordic Questionnaires, hand grip dynamometer, fitbit, gopro
- > results were that certain tasks were alot more physically demanding than others and that this poses a potential risk of injury (Cellar 1 and Bottler 2 expended most energy but drivers got the most steps)
