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117 Cards in this Set

  • Front
  • Back
Define anthropometry.
the science of measurement of body size.
From what scientific field does anthropometry originate?
What is the largest factor in the variance in anthropometric data?
Geographic Location
What is the anatomical landmark at the point where the hip and femur meet?
What is the anatomical landmark at the midpoint of the back of the knee?
Special Considerations for Measurements:
Slumped Standing/Sitting
Deduct 5-10% from appropriate height measurements.
Special Considerations for Measurements:
Relaxed Trunk
Add 5-10% to trunk circumference and depths.
Special Considerations for Measurements:
Wearing shoes
Add approx 25 mm to standing and sitting heights; more for "high heels"
Special Considerations for Measurements:
Wearing light clothing
Add approx 5% to appropriate dimensions.
Special Considerations for Measurements:
Wearing heavy clothing
Add 15% to appropriate dimensions.
Special Considerations for Measurement:
Extended Reaches
Add 10% or more for strong motions of the trunk.
Special Considerations for Measurement:
Use of hand tools
Center of handle is at about 40% hand length, measured from the wrist.
Special Considerations for Measurement:
Forward bent head (and neck) posture
Ear-eye line close to horizontal
Special considerations for Measurement:
Comfortable Seat Height
Add or subtract up to 10% to or from popliteal height.
Ten Types of Grip
1. Digit Touch
2. Palm Touch
3. Finger Palmar Grip
4. Thumb-Fingertip Grip
5. Thumb-Finger Palmar Grip
6. Thumb-Forefinger Side Grip
7. Thumb-Two-Finger Grip
8. Thumb-Fingertips Enclosure
9. Finger-Palm Enclosure
10. Grasp
How much error is expected in taking anthropometric measurements manually? (with experience) (error in the measurement itself)
~3% measurement error.
How much total error is expected in all anthropometric measurements?
Shortcomings of Using Classical Anthropometric Measurements (with a kit)
-time consuming
-many body landmarks cannot be projected onto grids
- contact measurements cannot be taken on sensitive parts
- body dimensions unrelated to each other (not a 3d Picture)
Modern Techniques of Anthropometry Measurements
Photograph, laser, video

Laser: distance-measuring device to measure the shape of irregular bodies

Markers: be placed on points of surface so that the laser can recognize them
Natural Sources of Variation in Anthropometry (not geographic location)
-condition (ex. pregnancy)
Steps of Collecting Anthropometric Data
1. Collect the Data
2. Calculate the statistics (mean, stddev, n)
3. Lookup Z-statistic (assume normal dist)
Our stature depends on _______.
Where our ancestors came from.
What condition must be met in order for someone to be standing straight upright?
-thumbs MUST be pointed outward
What is dynamic anthropometry?
-body data at work or to achieve a desired posture
Worst Case
Best Case
Worst case- excludes few, high variability in use of the system

Average- includes 50%, moderate variability in use

Best Case- includes few (5%)
little variability in use
Reach Envelopes
We dont reach from the center of the body, so design to the middle knuckle.
What country is the most homogeneous in anthro. data?
How does the body prefer to move?
In smooth, fluid arcs. NOT IN STRAIGHT LINES.
What happens at 83% arm length?
you shift your shoulders and lean in to complete the reach to conteract the weight of your arm
Movement in the abdomin requires 5X more muscle than arm movement, therefore...
...work should be kept below 83% reach.
At what position does a driver have the fastest reaction time in turns?
Neutral Posture (90 deg elbow bend). Therefore, design car so driver can sit in this position.
uses of 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 activity
Sometimes a few degrees away from neutral posture is the best design. Why?
To Minimize fatigue.
Occupational Biomechanics
a science concerned with the mechanical behavior of musculoskeletal tissues when physical work is performed. (machine, tool, or just the environment)
Design is 80% ____, 20% ____.
80% science, 20% feel.
Six factors of Occupational Biomechanics
1. Kinesiological Methods
2. Biomechanical Modeling Methods
3. Anthropometic Methods
4. Mechanical Work Capacity Evaluation Methods
5. Bioinstrumentation Methods
6. Classification and Time Prediction Methods
Epidemiological Support for Biomechanics
- More than 20 million people in the United States have musculoskeletal impairments.
- The majority of the population is at some time affected by back pain.
- Musculoskeletal conditions rank second only to diseases of the circulatory system on total economic cost and are the primary cause of lost earnings and non-fatal illnesses
- Soft tissue injuries (back & motion) account for 39% - 50% of worker's compensation claims.
- Cost of motion-related injuries including insurance treatment and lost earnings is $27 billion annually.
Why do women have a greater range of motion?
Because women have less muscle mass.
Factors Affecting Range of Motion
1. Age
2. Gender
3. Anthropometric Dimensions
4. Multiple-joint muslce effect (ex, spine)
Types of Biomechanical Models
- Planar (2D) Static
- Three Dimensional Static
- Dynamic (2D)
- Special Purpose (foot slip, low back, wrist and hand- coefficient of friction added in for these)
What body part is capable of every type of movement?
force applied over distance.
Units will be in lbs for our problems.
Must bring things back to perpendicular to get true tension (use trig functions)
What is inter-rater reliability?
compares the reliability/consistency of multiple observers
Abdominal Fluid
How to measure is unknown and highly variable. Abdominal Fluid assists the trunk while lifting.
What occupations have the most injured workers?
1. Professional Fisherman
2. Nurse (with most severity)
3. Professional Driver
Nurse lifting patient
3400N of stress placed on nurse's back. Nurse must lunge to raise patient up onto the toilet. Furthermore, duration of lift is increased due to pauses.
Type of Control
Administrative Controls (rules, hiring employees, programs, etc.)

Engineering controls (typically physical changes)
Levels of Control
1. Fail Safe- "low level", prevents nothing

2. Preventative- "mid level", guarding/limiting

3. Exclusionary- "high level", eliminate it
Define Physiology
The Study of the functions of the body parts, i.e. How the body parts work.
Exercise Physiology (goal, target pop, environment)
Goal: Maximize the physiological efficiency of the target population.

Target Population: fit, healthy, young, and motivated

Environment: Usually optimum or controlled
Work Physiology (goal, target pop, environment)
Goal: to ensure worker can perform task efficiently and safely within the envrionment

Target Population: all kinds of people

Environment: usually not optimal or controlled (noise, heat, etc.)
How do we USE work physiology?
To enhance efficiency- to monitor energy expenditure and avoid excess fatigue.

To ensure safety- do not push people beyond their physical limitations.
How many calories (max) should be consumed per day when undergoing severe work?
How many calories (max) should be consumed per day when performing heavy work?
How many calories (max) should be consumed per day when performing moderately heavy work?
How many calories (max) should be consumed per day when performing light work?
What is the total number of leisure calories + basic metabolism calories?
How many calories are for basic metabolism?
What are the FIVE factors effecting physical performance?
Somatic- sex, age, dimensions, health

Nature of Exercise- intensity, duration, rhythm, technique, position


Psychic Factors- attitude, motivation

Environment- altitude, high gas pressure, heat, cold, noise, air pollution
Two types of Fatigue
Central- nerve related (often caused by vibration)
Peripheral- muscle related
Effects of Aging
- decline starts at about age 30
- progressive loss of muslce mass
- lost muscle tissue replaced by fat
- decrease in maximal strength
- diminishing of muscle reflexes
MAC and heartrate are _____
What is MAC?
Maximum Aerobic Capacity- the maximum metabolic rate (or oxygen uptake) that an individual can obtain while breathing air at sea level.
- usually requires blood sample
- can also evaluate with VO2
What is MAC used for?
- capacity and fitness measures of individual workers or groups of workers

- classification of workers

- task design

- worker placement and evaluation

MAC was used to develop gatorade.
What method is used for Maximum MAC test?
Bike Ergometer
What method is used for Submaximal MAC test?
Tread Mill
Estimator/Heart Rate Test
Step Test
What are the criteria for MAC testing?
- workload must involve large muscle groups

- workload must be measurable 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, how accomplished)
Concept: Increase workload until VO2 "levels off"

How accomplished:
- estimate workload and "drop person on it"
- use gradual increases in workload

- very accurate
- dangerous (pushes people to limit)
- Motivation dependent
MAC: Submaximal Test (Concept, how accomplished)
establish an individual's MAC based on task performance at submaximal levels

How Accomplished:
- stress individuals at submaximal load
- record HR and VO2 for each load
- estimate MAC on basis of max age predicted heart rate

Percent Working Capacity- a measure of the effect of a task relative to an individual's maximum capacity

PWC = (Task VO2 / MAC) * 100%
What is Maximal Heart Rate?
Maximal HR = 220 - Age
What is an acceptable range of resting pulse?
65-85 bpm
What should the heart rate be between at moderately heavy work?
Not constantly > 120-150 bpm
Heart Strain, Method 1
Heart Strain = (Task HR / (220-Age)) * 100%

Should be <65%
Heart Strain, Method 2
Heart Strain = ((Task HR - Resting HR)/(220-Age-Resting HR)) * 100%

Should be <50%
At what percent of MAC will workers self pace for 8 hours shifts?
What is the common design criteria in terms of MAc and HR?
Common task and design criteria is 33% of MAC with HR of 105-115 BPM.
Ergonomics uses physiological responses to address both ____ and ____ issues.
efficiency, safety
Responses of the ____ and ____ systems are most accessible for evaluation.
respiratory, cardiovascular
____ ____ and ____ ____ are the most frequently used measures...but particularly ____ ____
oxygen uptake, heart rate, heart rate
____-____ ____ are used to practically achieve efficiency and safety goals.
work-rest cycles
Musculoskeletal Disorders- 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 the thumb

Trigger finger- specialized case of tendosynovitis in the fingers- related to De Quervain's- originally diagnosed from shooting guns- rebound of the trigger cuts into soft tissue.

Epicondylitis- "tennis elbow"

Tendinitis- tendons become locked due to sheath swelling

Raynaud's Syndrome- "white finger"- many who had trigger finger develop this

Herniated Spinal Disk

Thoracic Outlet- compression of nerves and blood vessels between the clavicle and 1st and 2nd ribs

DVT - pooling of the blood in the legs and feet from low level vibration- usually in people w/ high BMI

Ganglion- "bible thumber"- Ganglion cyst- in outer wrist
General Elements of Job Analysis
- Identify potential or existing problems
- Analyze job exposures and determine risk factors
- Evaluate risk factors in existing or proposed task
Passive Surveillance
-review of literature or work related injury information- OSHA logs, statistical reports, etc.
-provides good history of more serious and costly injuries...and associated economic cost
Active Surveillance
-active observation of work activity...e.g. safety audits, discomfort surveys, unsafe behavior checklists, etc.

-being "proactive"

- describes current concerns and behaviors...may provide indications before serious problems/injuries develop
"Anticipative" Surveillance
- prior to startup
- required when no job activities are planned...e.g. Review of literature, simulation, expert opinion, etc.
What are some of the useful bio-mechanical tools?
NIOSH Lifting Guides, Psychophysical Guides, RULA, REBA, OWAS, Michigan 2D/3D, ACGIH TLV's
What does Michigan 2-D/3-D do?
predicts stress on the lower back
What does the ACGIH TLV do?
set exposure limits for all chemicals

American Conference of Governmental Industrial Hygenists Threshold Limit
What are the three phases of job analysis?
1. Identification
2. Analysis
3. Evaluate
What are three types of identification?
1. Passive Surveillance
2. Active Surveillance
3. Anticipative Surveillance
What does the analysis phase involve?
-determining job attributes (aka risk factors) that could increase the probability of occurrence of the injuries of concern

-may use checklists, job surveys, videotape analysis
What does the evaluate phase of job analysis entail?
-performance of an in-depth risk factor evaluation to quantify risks associated with specific tasks
What is the Delphi approach?
method using expert operators to perform evaluations
Ergonomic Stressors (good for any job)

A few examples:
-inadequate leg clearance
-forceful grasping, pressing, pinching objects
-bending or twisting of wrist
-twisting of back
-workings with arms and hands above shoulders
How much of your body's weight is above the waist?
What part of the body do nurses complain about the most?
RH knee...pressed up against bed when turning patients/administering care
Back Injury Statistics
Back Injuries- nearly 20% of all injuries and illnesses in the workplace

Back Injuries- nearly 25% of the annual worker's compensation payments

Overexertion- most common cause of occupational injury, 31% of all injuries

Back- body part most frequently injured (22% of 1.7 million injuries)
How much can a person lift safely?
Threshold value is 51 lbs. Reduces for present conditions.
Manual Material Handling Activities (6)
- Lifting (while standing)
- Pulling
- Lowering
- Carrying
- Lifting (while sitting)
- Pushing
MMH Guidelines
Psychophysical (Lifting, Lowering, Pushing, Pulling, Carrying)

NIOSH (Lifting)

Job Stress Index (JSI) (Lifting)

Use at least two when evaluating
What does NIOSH stand for? What do they do?
National Institute of Occupational Safety and Health- research and make recommendations to OSHA.
What factors affect MMH?
- worker characteristics
- material/container characteristics
- task characteristics
- work practices
Assumptions associated with NIOSH lifting guide
- Smooth lifting
- moderate width objects (hand separation of less than 75cm)
- unrestricted lifting postures (no bracing of torso)
- good couplings (handholds are secure and show/floor slip potential is low)
- favorable temperature conditions
NIOSH Variables
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 down when load is moved

F: How often load is moved

E: Environment (head, dust, etc.)
How long is "long duration" when referring to the frequency multiplier (FM)?
longer than four hours
How long is "moderate duration" when referring to the frequency multiplier (FM)?
1-4 hrs
How long is "short duration" when referring to the frequency multiplier (FM)?
What are the shortcomings of the NIOSH lifting guide?
- no consideration for asymmetrical lifting
- no consideration of inertial forces
- no provision for push-pull activities
What does RULA stand for?
Rapid Upper Limb Assessment
What does REBA stand for?
Rapid Entire Body Assessment
RULA (probably not on exam)
- straight forward, minimal training
- not a validated tool
- quick survey method for ergo investigations
- focuses on neck, trunk, and upper limbs
- end result breaks job into 4 classes. Class IV is not acceptable
REBA (probably not on exam)
- used to animate load handling
- quick, systematic assessment of the complete body postural risks
- 144 posture combinations
- similar to RULA, but includes lower body too
BORG Scales
Perception Scale- 3 is Moderate, 10 is extremely strong. Job should be a 3, overall.