Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
69 Cards in this Set
- Front
- Back
Anthropometry falls between with human sciences?
|
Ergonomics and Human Factors
|
|
Anthropometry definition
|
science of measurement of body size
|
|
Forearm length measurement
|
elbow-to-fingertip distance
|
|
stature measurement
|
starts at floor on which the subject stands and extends to the highest point on the skull
|
|
height measurement
|
vertical point-to-point, straight - line
|
|
breadth measurement
|
horizontal point-to-point, straight-line
|
|
distance measurement
|
straight-line, point-to-point measurement between landmarks on the body
|
|
curvature measurement
|
point-to-point measurement following a contour
|
|
Measurement considerations
|
accounting for clothing based on environment; neutral position; account for functional work positions
|
|
Modern techniques for measurements
|
Photograph, video, laser-based anthropometry
|
|
Natural sources of variation
|
by stature, shape, condition (pregnant), and age
|
|
What is a reach envelope?
|
functional area your arm can move
|
|
What's included when designing for the worst case?
|
includes lots of people, with high variation
|
|
What's included when designing for the average case?
|
includes 50%, less variation
|
|
What's included when designing for the best case?
|
includes 5%, very little variation
|
|
#1 rule when designing something?
|
Know who you're designing/marketing for
|
|
Traditional reach envelopes?
|
measure from middle knuckle to elbow then elbow to shoulder; tip of finger bc not leaning forward
|
|
Our job for designing as IEs
|
Ergonomics, Safety, Human Factors
|
|
When designing something, where do we start?
|
Start at a midpoint or a stationary point (e.g. hip with car, feet with workstation)
|
|
2nd rule when designing:
|
get to neutral posture (most comfortable)
|
|
Definition of biomechanics
|
uses laws of physics and engineering concepts to describe motion undergone by the various body segments and the forces acting on these body parts during normal daily
|
|
Occupational Biomechanics definition
|
interacting with the environment around you that pertains to a job
|
|
Criteria for lifting on the job
|
51 lbs and lower depending on the job
|
|
List the range of motion measurement methods (2)
|
Goniometry and Spatial Imaging (photography - 2D and motion capture - 3D)
|
|
Traditional factors affecting range of motion data
|
age, gender, anthropometric dimensions, multi-joint muscle effect (e.g. spine) - range of motion from all joints acting together, BMI - more space taken up, less range
|
|
Three types of lever systems in the body
|
First Class Lever, Second Class Lever, Third Class Lever
|
|
First Class Lever
|
Center of rotation (fulcrum) is located between the resistance (load) and force (muscle) on either end of the lever, e.g. head
|
|
Second Class Lever
|
Fulcrum is located on one end with the resistance located between the fulcrum and force (muscle), e.g. ankle
|
|
Third Class Lever
|
Fulcrum located on one end with the force in between the fulcrum and the resistance, e.g. elbow
|
|
Types of Biomechanical models (4)
|
-Planar (2D) Static - single body segment, two body segment, non-parallel force, internal force, multiple link
-3D Static -Dynamic (2D) - single segment, multiple segment -Special Purpose - foot slip model, low back, wrist and hand |
|
Load
|
Application of vertical load applied to a horizontal distance
|
|
Measuring shoulder - start at?
|
Hands
|
|
Measuring low back - start at?
|
feet
|
|
Types of controls:
|
Administrative Controls - rules, hiring employees, programs
Engineering controls - typically physical changes (conditions, environment) |
|
Levels of Controls:
|
1. Fail - Safe - "Low level", preventing nothing, barriers or dilution only (administrative, stickers, memos)
2. Preventative - "Mid Level". guarding/limiting (guard around turning shaft) 3. Exclusionary - "High Level", eliminate it (remove condition entirely) |
|
Physiology:
|
Study of the functions of the body parts, i.e. How the body parts work
|
|
Exercise/Work Physiology:
|
The study, description, evaluation, and explanation of the physiological changes in the human body resulting from either a single or repeated series of exposure to work stresses
|
|
Exercise Physiology:
|
Goal - maximize the physiological efficiency of the target population
Target population - fit, healthy, young, and motivated Environment - optimal or controlled |
|
Work Physiology:
|
Goal - to ensure worker can perform task efficiently and safely within the environment
Target Population - all kinds of people Environment - usually not optimal or controlled |
|
We use work physiology to enhance efficiency by:
|
Monitoring energy expenditure and avoid excess fatigue
|
|
We use work physiology to ensure safety:
|
do not push people beyond their physical limitations
|
|
Three categories of workload system changes:
|
1. Circulation - increases with work
2. Respiration - increases with work 3. Blood - decreases some or stays same with work |
|
VO2 =
|
HR * SV * (a-vo)
|
|
Metabolic Rate:
|
Starts at 2500kcal/day and increases according to work level
Basic Metabolism = 1500 Leisure = 1000 |
|
5 Factors affecting physical performance:
|
1. Environment - Altitude, high gas pressure, heat, cold, noice, air pollution
2. Psychic Factors - Attitude, motivation 3. Training - adaptation 4. Somatic factors - sex and age, body dimensions, health 5. nature of exercise - intensity, duration, rhythm, technique, positions |
|
Two types of fatigue
|
1. central - nerve related (fingers lock up after vibration)
2. peripheral - muscle related |
|
Effects of aging:
|
Decline starts at about 30 yrs
Progressive loss of muscle mass Lost of muscle tissue replaced by fat Decrease in maximal strength Diminishing of muscle reflexes |
|
Designing for efficiency:
|
- use heart rate to evaluate energy usage
- use Maximum Aerobic Capacity - design work for light to moderate energy expenditure |
|
Maximum Aerobic Capacity
|
The maximum metabolic rate (or oxygen uptake) that an individual can obtain while breathing air at sea level.
|
|
MAC: The Basics - three types of testing
|
1. maximum test - bike ergometer
2. submaximal test - tread mill 3. estimator/heart rate test - step test |
|
MAC: The Basics - Criteria for testing
|
- workload must involve large muscle groups
- workload must be measureable and reproducible - test conditions must be reproducible - test or workload must be tolerated by normal, healthy people - mechanical skills needed to perform the workload must be uniform and common in tested population |
|
MAC: Maximal Test
|
Concept: increase workload until VO2 "levels off"
- estimate workload and "drop person on it" - use gradual increases in workload - very accurate - dangerous - motivation dependent - extend maximal limit |
|
MAC: Submaximal Test
|
Concept: Establish an individual's MAC based on task performance at submaximal levels
- stress individuals at submaxial levels - record HR and VO2 for each load - estimate MAC on basis of max age predicted heart rate - less accurate than Max Test - less dangerous than Max Test |
|
Percent Working Capacity (PWC)
|
A measure of the effect of a task relative to an individual's maximum capacity
PWC = Task VO2/MAC *100% |
|
Workers "self pace" at:
|
33 - 44% of MAC for 8-hour shifts
|
|
Common task and design criteria is:
|
33% of MAC with HR of 105-115 beats/min
|
|
Musculoskeletal Disorders (MSDs)
|
Occupational medicine job-related injuries and disorders of the muscles, nerves, tendons, ligaments, joints, cartilage, spinal disks"
|
|
Common MSDs
|
Carpal Tunnel
Rotator Cuff De Quervain's disease - specialized case of tendosynovitis in thumb Epicondylitis - tennis elbow tendinitis - tendons become lock due to sheath swelling Raynaud's Syndrone - "white finger" Herniated spinal disk Thoracic Outlet - compression of nerves and blood vessels b/w the clavical and 1st &2nd ribs Deep Vein Thrombosis - pooling of the blood in the legs and feet from low level vibration Ganglion - bible thumber |
|
Identification:
|
Passive, Active, "Anticipative" Surveillance
|
|
Analysis:
|
Determining job attributes that could increase the probability of occurrence of the injuries
|
|
Evaluate:
|
To perform in-depth risk factor evaluation to quantify risks associated with specific tasks
|
|
Factors affecting MMH
|
Worker Characteristics, Material/Container Characteristics, Task Characteristics, Work Practices
|
|
Assumptions Underlying NIOSH Lifting Guide
|
Smooth Lifting
Moderate width objects unrestricted lifting postures good couplings favorable temperature conditions |
|
Things To Look for when Studying MMH
|
W - amount of weight being lifted
P - posture while lifting H - horizontal location of load V - vertical location of hands when load is picked up D - Distance load is moved up or down A - amount of twisting done when load is moved F - how often load is moved E - environment |
|
Frequency Multiplier
|
Based on vertical component
|
|
Coupling Multiplier
|
Good
Fair Poor |
|
Deficiencies in NIOSH Guide
|
- no consideration of asymmetrical lifting
- no consideration of inertial forces - no provision for push-pull activities |
|
REBA
|
Rapid Entire Body Assessment - quick and systematic assessment of the complete body postural risks to a worker (accounts for Lower Body)
|
|
RULA
|
Rapid Upper Limb Assessment - quick survey method for use in ergonomic investigations of workplaces where MSD's are reported
|