BPK 180 Midterm
What are the basic types of muscle injuries?
"Strains"→ injury to muscles or tendons Muscle Fatigue: →MVC= maximum voluntary contraction up to 15%, or up to 5% for static contractions (in an 8 hour work day, this should be the maximum average) Delayed Onset Soreness (DOS): →not an indication of strain, just a sign of extra exertion Acute Injuries→ contusions, avulsions
What information about injuries is important to gather in an ergonomics evaluation?
--Types of Injuries-- Incidence: "number of new cases that come into being in a specific time period" Prevalence: "number of new cases as a % of the number of workers" Severity: "the seriousness of the injury" Incidence DOES NOT equal prevalence (depends on the size of the company)
What are the 10 characteristics of WRMSDs?
1. Effect muscles, tendons, nerves or vascular system 2. Are beginning to plateau in the workplace 3. Mechanical and physiological process 4. Related to work duration and intensity (force, repetition, awkward posture) 5. Requires weeks, months or years to develop 6. Requires weeks, months or years to recover; little is known about the recovery process 7. Poorly localized, non-specific and episodic 8. Often unreported 9. Multiple work and personal causes; the interaction of which is poorly understood 10. Repair leaves tissue stronger and more suited to the task (adaptation; does not mean you are less prone to getting injured again though)
Why is it difficult to say that a musculoskeletal disorder is work-related?
1. May not be a direct cause and effect, but an interaction between many factors 2. Little is known about the interaction of factors 3. Some WRMSD are ideopathic 4. Many risk factors are part of everyday life 5. More than one WRMSD can exist at any one time 6. Individuals react differently
What are the 7 steps to conducting an ergonomics evaluation?
1. Planning 2. Assessing Need/Benchmarking 3. Gathering Background Information 4. Risk Identification 5. Risk Assessment 6. Risk Control 7. Evaluation or Monitoring
Give a list of engineering controls you may suggest in an ergonomics assessment.
1. Promote a neutral posture in the upper limb 2. Use jigs and fixtures to avoid "biological clamp" 3. Provide limb support to reduce static load 4. Suspend tools 5. Avoid cervicobrachial compression 6. Eliminate contact stress points 7. Be transparent about the placement of handles 8. Ensure anthropometric fit of hand object 9. Allocate difficult tasks to the tool 10. Minimize the weight of the object held or supported 11. Reduce torque 12. Provide handles with textured handholds 13. Choose power activation over manual 14. Bend the handle, not the wrist 15. Design the product to be used by either hand 16. Avoid single trigger mechanism and hyperextension of the thumb 17. Cover all metal surfaces which contact the skin 18. Eliminate vibration between 8 to 500Hz with accelerations of 15 to 800m/s² 19. Consider anti-vibration gloves (administrative control) 20. Ensure that the product can be easily maintained 21. Reduce task psychosocial stressors 22. Reduce role psychosocial stressor
What are the 5 resources of strategies for risk control of an ergonomic evaluation?
1. Standards: ∙Canadian standards association (CSA) ∙International standards association (ISO) [not necessarily enforced by law, but are guidelines to work towards] ∙British standards institute (BSI) ∙German Standards Association (DIN) ∙Military Standards (MIL-STD) 2. Guidelines: ∙Workers' Compensation Boards (ie. WorkSafe BC) ∙National Institute of Occupational Health and Safety (NIOSH) ∙Discussion papers ∙Research papers ∙Occupational Health Institutions (IWH, CCOHS, Universities) 3. Case Studies ∙In the academic literature ∙In the "grey" literature ∙Anecdotal experience form same or other industries 4. Discussion with Workers and Management ∙Experienced workers ∙Workers who have worked in same industry but different work places *Often the best people to come up with solutions that will stick= more buy in, knowledgable 5. Ergonomists
What are the 7 main needs for ergonomics today?
1. ↑ Injuries →Workplace injuries are on the rise, particularly musculoskeletal injuries (MSI) 2. Changing Workforce ∙A more diverse workforce means that workplace design and job demands must reflect a wider range of worker capabilities and limitations (age, size, strength, abilities) →Fair and effective worker placement (ex. firefighter protocols), Architectural design, Workstation design, Tool design, Training, Job design 3. Changing Work ∙Work is changing as well- increased shift work, work from home/vehicle, flex time/part time →Psychosocial issues, Management styles, Organizational design, Job design, Physical design issues →New issues= vibration, higher g-forces, weightlessness) 4. Quality/Productivity Goals ∙Increased pressure for productivity and quality: total quality and continuos improvement programs →More comfortable workers are able to work more efficiently (engineering controls often reduce unnecessary production steps & allow for improved quality) 5. Regulations/Legislation ∙Regulatory activity has increased. Companies are searching for programs to help with compliance →Every workplace in BC is required to have an ergonomics committee 6. Increasingly Complex Technologies and Systems ∙Three Mile Island/Chernobyl/Hinton Rail Disaster →Ergonomic methodologies allow for a systematic view of the operation to determine potential areas of human error 7. Consumer Products ∙Difficult to use, Difficult to understand, Difficult to learn, Physical injuries
What are tendons and ligaments and what kinds of injuries can they face?
Connective tissue functions: →fibrous container for soft tissues →transmitting mechanical forces (tension) →tendon= muscle-bone →ligament= bone-bone →Highway for blood vessels & nerves Injury affects these functions! "Sprain"- injury to ligament (chronic or acute)
What kinds of connective tissue are most common in ligaments, tendons, and muscles?
Connective tissue= matrix of ground substance, cells and mix of collagen and elastin ∙Collagen= high tensile strength, resists elongation ∙Elastin= low tensile strength, deforms greatly →Ligament doesn't have much elastin, tendons have a bit more, and muscles have the most elastin Lecture 3 Slide 13
What happens at the background information stage of an ergonomics evaluation?
Determining duties →Determine critical duties Determine critical tasks Use appropriate task description techniques →Prose →Process flow diagram →Link analysis →Hierarchical task description
Why is Fredrick Taylor a significant individual in the history of ergonomics?
Developed scientific management: concerned with efficiency →Looked at people as they worked, came up with redesigning the work station to improve efficiency →Looked at the amount the people could move with different kinds of shovels (first person to look at design in terms of workplace efficiency)
What is the healthy worker effect?
Effect whereby the healthy people in the workplace are older because all the injured people have left
What kinds of risk controls can be administered in the risk control phase of an ergonomics evaluation?
Engineering Controls: →Solutions which involve equipment, tools, environment and which make permanent changes to the workplace →Modification or a major change Administrative Controls: →Solutions which involve the way the job is organized: hours of work, rotation schedule
What does the term ergonomics mean?
Ergo ("work") + Comics ("the study of") →The science that addresses human performance and well-being in relation to the job, equipment, tools and environment →Fitting the job, equipment, tools and environment to the person NOT the person to the job, equipment, tools and environment
What is the cumulative load theory of injury development?
Material fatigue concept (at what point does the tissue fatigue and ultimately fail)→ wear and tear balanced by self repair (stress-recovery) ∙Repeated or sustained loading results in a reduced threshold for stress (stress at which failure occurs) ∙"cumulative load"= load x time (N.s) x repetitions (at what point are you going to create so many microtears in that tissue from repetition that it will start to cause pain, etc) ∙high load x low repetition = failure ∙low load x high repetition = failure Lecuture 3 Slide 20 & 21
How does the definition of ergonomics differ in North America and Europe?
North America: "Ergonomics"= physical factors "Human Factors"= cognitive factors Europe: "Ergonomics"= both physical and cognitive
What kinds of perceptual acuity would need to be considered when designing a workstation?
Perceptual acuity= 5 senses ∙Corrective lenses ∙Colour blindness ∙Auditory deficits ∙Tactility ∙Taste? ∙Smell?
What philosophical model is important when looking at ergonomics?
Person-Process-Environment Model!
What defines the primary and secondary work zones? Why is it important to distinguish between these zones?
Primary zone= everything from fingertips to elbow Secondary zone= everything from fingertips to shoulder Things/tasks done most frequently should be placed in the primary zone (also between shoulder and waist)
What is prose?
Prose is a written description of the task. It is usually sequential and is often used as a first step to other task description techniques
What engineering control might you use to reduce static load?
Provide limb support →Ergo arms (something just to be able to rest the elbow- to get the load off the shoulder) →Sometimes these can create more problems than it solves, if at the wrong height, etc.
What does each of the following stand for: RSI CTDS OOI ASTD O/E What general category do these terms fall under?
RSI→ Repetitive Strain Injury CTDS→ Cumulative Trauma Disorders OOI→ Occupational Overuse Injury ASTD→ Accustomed Soft Tissue Disorder O/E→ Overuse/Exertion All are WRMSDs (Work Related Musculoskeletal Disorders)= a group of activity-related disorders affecting muscles, tendons and other soft tissue (nerves or arteries) developed as a result of work-related activities
What is the difference between Raynaud's disease and vibration white finger?
Raynaud's disease= genetic disorder when exposed to cold, capillaries shut down and fingers turn white VWF: ∙Vascular disturbance of fingers ∙Severe cases can be occlusion and tissue atrophy ∙Blanching of extremities (When using a vibrating hand tool, the walls of the arteries are doubling in amplitude, ie. stretching beyond their capacity and damages the capillary tissue= no blood supply.→tissue dies and you have to cut off the ends of the fingers)
Where is the most common site of tendinitis in the shoulder?
Rotator Cuff: supraspinatus, infraspinatus, teres minor, subscapularis (also sometimes involves the long head of the biceps) ∙Inflammation of degeneration of the tendons of the rotator cuff or biceps
What are two tests used to diagnose rotator cuff tendinitis?
Speed's Test: resisted elbow flexion→ pain in long head of biceps Yergason's Test: resisted supination→ pain in long head of biceps
What aspects of physical fitness as affected in older workers that have an impact on workstation design?
Strength: ∙Gender differences (peak age 20 for males) ∙Age differences (strength ↓ w/ age, especially hand strength) Endurance: ∙High individual differences ∙Does not decline as fast as strength with age ∙O₂ update, maximal HR & SV all decrease with age ∙Heat tolerance (less of young children and elderly)
What engineering control would help if you were using heavy tools?
Suspend the tools!
What is occupational biomechanics?
The study of motion and forces in the human body due to the interaction of workers with their tools, machines and environment
What engineering control might you put in place to avoid a "biological clamp"?
Use jigs and fixtures →Holding onto a device causes the worker to absorb all the vibration and pressure
Give a brief timeline of the development of ergonomics through WWI, WWII, the 1960's/70's/80's, and into the present.
WWI: controls on planes were not intuitive= people were doing the wrong thing in stressful situations (need to develop more intuitive controls) WWII: Accelerated development of machines (ex. radar, aircraft, tanks) ∙Highlighted limitations of humans who had to use these machines (ex. vigilance failures of radar operators, g-forces, control locations) 1960's: More team based work, reducing repetitions 1970's: The computer revolution (keyboarding, interface design) 1980's: Consumer Revolution (product design came about, industrial designers becoming more aware of the need for ergonomics) 2000+: Information Revolution (How do we interact with devices? How do we deal with virtual reality?)
What are the engineering control guidelines for promoting a neutral posture of the upper limb? How can they be achieved?
Work height: ∙90° elbow ∙No should flexion/abduction ∙Neutral wrist (precision work= 10cm above elbow; force work= 10cm below elbow) Achieved by: ∙Adjustable workstations ∙Adjustable seating ∙Appropriately sized tools ∙Place equipment at an angle to support a neutral wrist ∙Keep the work directly infront of the worker (maintain neutral wrist postures, change the orientation of the work) ∙Ensure that controls, tools, and materials can be easily reached (placed between shoulder and waist height, reflect sequence of use)
In general, what is the cost of WRMSDs?
∙33% of WCB costs ∙50% of working population experience symptoms at least 1 day per year ∙20% of workers report back pain for at least one week over the pervious 12 months worked ∙17% reported hand pain ∙Estimated to cost $3 billion/year in medical costs and lost days to Canadian economy
What are the signs and symptoms of hand-wrist tendinitis & tenosynovitis?
∙Across radiocarpal joint ∙Swelling, pain, crepitus on passive motion (from Ca²⁺ from microtears), local tenderness, pain increased by resistive motions ∙Palpable tendon nodule, inflammatory signs ∙Palpable tendon nodule that is point tender ∙Vascular disruption, hematoma ∙Pronounced asymmetric grip strength (4kg)
What personal factors are associated with WRMSD's?
∙Age (wound healing slows with age) ∙Moderate to heavy smoking ∙Previous similar history ∙Inflammatory Disorders (arthritis) ∙Pregnancy (for CTS) ∙Diabetes mellitus ∙BMI
What knowledge does biomechanics provide to ergonomics?
∙Allows understanding of loading on the body ∙Assists in understanding of WRMSI mechanisms ∙Provides guidance for solutions
What are you looking for when looking at employee moral in benchmarking?
∙Are people satisfied ∙How much absenteeism is there ∙How much turnover is there Ex. Minnesota Satisfaction Questionnaire
What are the biomechanical applications to ergonomics?
∙Assessing the risk of injury of a task ∙Assessing the design of a product
What kinds of engineering controls can be administered to avoid cervicobrachial compression (TOS)?
∙Avoid single strap bags ∙Use jigs and clamps and elbow rests for overhead work ∙Reduce weight of load ∙Reduce high speed movements
How do you identify risks in an ergonomics evaluation?
∙Checklists ∙Worksheets (ex. WCB) Does not assess, it only identifies whether the risk MAY be there
Why is cold a risk factor to WRMSD?
∙Commonly cited as a risk factor for H-W although epidemiological evidence is weak ∙Appears to be related to reduced tactile sensation (same mechanisms as gloves) creating increased force ∙External temperature, compressed air, or conductive cold
What are the kinds of costs that an organization will face from WRMSD?
∙Compensation and Benefits (WCB, pension, wage replacement) ∙Additional Company Benefit Costs (accident insurance, wage replacement) ∙Legal Costs (fees for external council, expert witness, fines, settlements) ∙Time/Productivity Losses (cost of production replacement, employee time spent in post accident activities, ↓ productivity losses due to accident) ∙Material Equipment and Property Damage ∙Public Relations ∙Corporate Image ∙Pain and Suffering ∙Employee Morale ∙Psychological Impact
What are 3 ways in which a nerve can be injured?
∙Compression ∙Tension Severed
How might psychosocial issues contribute to WRMSD?
∙Contribute to aetiology of disorders ∙Influence whether workers report injuries or not ∙Success of rehabilitation or return to work programs (How people feel at work, whether they get along with their coworkers, do they often miss work, etc.)
What kind of task psychosocial stressors would you want to reduce as an engineering control in an ergonomics assessment?
∙Cumbersome or arbitrary procedures ∙Simplicity-complexity ∙Monotony-variety ∙Technological issues ∙Work pressure ∙Cognitive demands
What kinds of information is important to get when gathering background information in an ergonomics assessment?
∙Defining the job ∙Defining the tasks ∙Selecting critical tasks ∙Describing activities
What are tendons?
∙Dense tissue, mostly collagen fibres with few cells, or blood vessels ∙White, heal slowly (not much blood supply) ∙Collagen fibres highly organized into parallel bundles with cross-links ∙Stress-Strain curve follows collagen curve
What are the design consequences of knowledge and experience variability?
∙Design or work procedures ∙Info design ∙Interaction design ∙Training design ∙Team development
Describe the purpose of the planning stage in an ergonomics evaluation.
∙Determine objectives, needs and concerns →Include all parties at initial meetings (important to try to involve as many people as possible) →Provide education about benefits of ergonomics →Review organization's mission statement (bigger buy-in if you can tie recommendations to the mission statement) →Write objectives down and refer to them ∙Clarify you role and objectives ∙Identify key decision makers ∙Clarify ethical responsibilities
What are the steps to conducting a link analysis?
∙Determine purpose: →what are you tracking and why? ∙Sketch the physical system ∙Draw links (arrows) ∙Number links to define sequence ∙Prioritize links (frequency, criticality, etc) ∙Rearrange the system (optimize) based on your defined purpose and prioritization
What is a discomfort survey and what is it used for?
∙Diagram of a body or part of body ∙Indicate on each body part you degree of discomfort from: 0= no discomfort → 10 Extreme Discomfort ∙Will not find these as part of safety records ∙Administer to a group of workers (healthy workers, visual analog discomfort scale or verbal scale) ∙One point in time, or over a shift
How does knowledge and experience vary in a workplace?
∙Education level ∙Skill level (reading, typing) ∙Task knowledge ∙Task experience (high, low) ∙Time to learn job ∙Languages (speak, read, write) ex. people are used to a red light meaning stop, so do not suddenly make green mean stop and red mean go
Where do you find production data for benchmarking?
∙Engineering records ∙Supervisors, Managers ∙Employee anecdotal reports
What is carpal tunnel syndrome? What are the signs and symptoms?
∙Entrapment or injury of the median nerve in the carpal tunnel (result of deem in tissues around the tunnel) ∙Cannot get carpal tunnel without having tendinitis before ∙Pregnant woman and diabetics are more prone to CTS b/c of edema S & Sx: ∙Pain, numbness, or tingling in the median nerve distribution of hand and fingers (tend not to feel pain in the wrist) ∙Nocturnal exacerbation (gets worse at night- probably because sleep in awkward positions) ∙Increased compression in tunnel (normal 3mmHg) ∙Reduced nerve conduction velocity (normal 45-75m/sec)
What forces are considered "high" and will be a risk of WRMSD?
∙Exertion >60% MVC avoided ∙>4Kg grip force increases risk ∙>2Kg pinch grip increases risk ∙Frequent action up to 30% MVC ∙Continuous action up to 15% MVC ∙Sustained static exertions greater than 5% MVC problematic
What are the signs and symptoms of stenosing tenovaginitis (aka. trigger finger)?
∙Fibrous thickening of the tendon sheath in the flexor tendons of the hand ∙Results in snapping movement of finger due to swelling and restricted gliding of the tendon ∙"Locking usually occurs" during flexion/extension (cannot extend the finger at all) ∙Nodule usually present on tendon
What are the signs and symptoms of deQuervain's disease?
∙Fibrous thickening of the tendon sheath in the flexor tendons of the thumb ∙Pain in the anatomical snuffbox with possible radiation up forearm ∙Positive Finkelstein test
What are some physical characteristics of the individual that can impact workstation design, hand tool design, vehicle design, etc?
∙Gender ∙Age ∙Height, weight ∙Anthropometry ∙Handedness- right, left, ambidextrous ∙Physical challenges- injury, mobility
What is a link analysis and why do we do it?
∙Graphical representation of the relationship between components within a system ∙Activity relationship charts describe the communication needs between several human or between humans and machines ∙Spatial organization of activities, frequency, importance, sequence ∙Used for: material handling, traffic flow, communication, workstation layout, interface design...
What are the major industries affected by WRMSDs in BC?
∙Health Industry (tends to be most common in long term care facilities) ∙Retail ∙Forest Industry ∙Office Environments ∙Mining ∙Construction ∙Food Processing
What kinds of things are important to note in benchmarking in an ergonomics assessment?
∙High incidence of injury/discomfort ∙High severity of injury or discomfort (mild/chronic/etc) ∙Low production levels ∙High error rates ∙Poor quality (ex. how many returns of products) ∙Poor employee moral/job satisfaction ∙Used as a benchmark- Information gathered should be used for before and after evaluation
Why are awkward postures considered a risk factor to WRMSD?
∙Increase internal load on tendons ∙Increase pressure in carpal tunnel ∙Increase friction over bones Confounding factors in the research- body size (function of body size, technique)
What physiological changes can result from cumulative load?
∙Inflammation and swelling ∙Stimulate nociceptors (pain) ∙Increased muscle tension to reduce motion ∙Increased synovial fluid in tendon sheath ∙Chronic joint pain Lecture 3 Slide 25
What is bursitis?
∙Inflammation in the bursa sac in the joint ∙Small fluid-filled sacs in joint ∙Cushion pressure points between bone and tendon
What do you want to measure in benchmarking?
∙Injuries ∙Discomfort ∙Production measures ∙Employee moral
What factors affect force as a risk factor of WRMSD?
∙Lever arm (torque) ∙Internal vs external load ∙Force velocity ∙Strength-endurance ∙Rest time ∙Tolerance of tissue ∙Grip type ∙Posture ∙Grip size ∙Gloves (don't have sensory feedback to prevent you from overgripping)
What is a contact stress and why is it a risk factor to WRMSD?
∙Mechanical stresses produced in the area of contact with external object (ex. things digging in, hand tool handle not fitting very well) ∙Some evidence for CTS and digital neuritis
At what point does vibration become a risk factor for WRMSD?
∙Mechanism- occlusion of blood vessels ∙15 to 800m/sec² and frequencies of 8 to 500Hz are of concern ∙Exposure limits set by ISO
Give examples of the consequences of design of a workplace when not accounting for physical differences.
∙Missed auditory signals (alarms, alerts) ∙Layout issues for communication ∙Training ∙Layout at workstations ∙Lighting ∙Colour coding of info
How do ligaments differ form tendons?
∙Mostly collagen ∙Fibers are less organized (tends to be more brittle)
What kinds of psychological variability do we commonly see in a workplace?
∙Motivation (high or low) ∙Attitude (like/dislike, hard/easy) ∙Ability to learn ∙Interest ∙Cognitive challenges (dyslexia) ∙Cultural/social characteristics
What are some design consequences of workplaces when looking at psychological variability?
∙Motivation programs ∙Training design ∙Management style
What is thoracic outlet syndrome?
∙Neuromuscular disturbances cause by compression of the neuromuscular bundle at the thoracic outlet ∙Fibrous bands/cervical rib (malformations-some people are just born with an extra rib and that can cause everything to be pushed up)
What are some methods for information collection in ergonomics?
∙Observations- users in situation ∙Interviews- structured, unstructured ∙Questionnaires- general, specific questions ∙Focus groups- on tasks, problems, future
What are the signs and symptoms of rotator cuff tendinitis?
∙Painful arc, more apparent on active restricted movement than passive ∙Nocturnal symptoms (gets worse at night, tendinitis in the wrist does NOT) ∙Crepitus ∙Subacromial tenderness ∙Referred pain along C5 distribution ∙Pain in anterior shoulder which increases with abduction
What are the risk factors to WRMSD in the literature?
∙Personal Factors ∙Repetition ∙Force ∙Awkward Postures ∙Duration ∙Vibration ∙Cold ∙Contact Stresses ∙Psychosocial Issues
What characteristics will affect behaviour with the system of conducting an ergonomics evaluation?
∙Physical characteristics ∙Psychological characteristics ∙Knowledge and experience
What are some of the contributing fields of knowledge to ergonomics?
∙Physiology ∙Psychology ∙Biomechanics ∙Environmental Studies ∙Anthropometry ∙Sociology ∙Business ∙Engineering ∙Design
What are two clinical tests done to diagnose carpal tunnel syndrome?
∙Positive Phalen's test (60-80% detection) →Put dorsal side of hands together infront of body with fingers pointing downwards ∙Positive Tinel's sign →Touching the carpal tunnel If motor branch is involved, you will have decreased strength or atrophy of Thenar muscle (fairly rare)
What information is important to gather when looking at production data in benchmarking?
∙Production rates- changes within a shift, within a week, between workstations (cycle time, ppm, standard time) ∙Poor quality- rework, rejects, returns... ∙Error rates- product returns, breakage, down time, costs...
How might you eliminate contact stress points to as an engineering control?
∙Put some padding ∙Soften the edge ∙When there are grooves for holding on a handgrip for a tool and your hand does not actually fit, this can be detrimental
What is repetition and why is it a risk factor to WRMSD?
∙Refers to a series of motions performed over and over again by the same muscle groups ∙Expressed as movement or exertions/time ∙Macro and micro trauma as a result of tendon deformation (& reduced tolerance of the tissue) ∙Cycle less than 30sec and/or 50% of cycle time involved in same motion pattern is considered a repetitive risk factor
What aspects of muscle tissue are important in the consideration of injury?
∙Resilient, strong, elastic ∙Resists injury ∙Highly vascularized so heals rapidly ∙When injured, often at myotendinous junction (concentration of force, less elasticity--start to get microtears in the tendon)
How do you monitor an organization after you have conducted your ergonomics assessment?
∙Return to the job site →1 month, 6 months, 1 year later ∙Re-evaluate benchmark data →Injury →Discomfort →Production →Morale ∙This step is required by legislation in BC
What two tests are used to diagnose thoracic outlet syndrome?
∙Roos test: "arrested stance"→ pain, heaviness or profound arm weakness or numbness and tingling of the hand ∙Allen test: radial pulse is palpated and if it disappears as the patient's head is rotated the test is considered positive
How and why would you develop a user profile in an ergonomics assessment?
∙Starting point for making design decisions→ should not make a design decision without referring to the user profile ∙Consult a user profile team →Customer service, training, marketing, etc. →Use questionnaires, focus groups, interviews ∙Brainstorm a preliminary list →Discuss how users define themselves, individual differences, how users change over time
In an ergonomic assessment, how do we understand what the users needs and capabilities are?
∙Surveys of the types of users ∙Scientific information about human variability →Anthropometry →Biomechanics →Physiology →Injury development....
What are the 2 important structures in a joint?
∙Synovial fluid →thixotropic lubricant →rapid motion, low viscosity; slow motion, high viscosity ∙Joint capsule →sheet of collagen fibres, proteoglycans and elastic fibres surrounding joint
What is the purpose of risk assessment in an ergonomics evaluation?
∙Task description and task analysis ∙Biomechanical models ∙Physiological models ∙Guidelines ∙Formulae
What are the signs and symptoms of epicondylitis?
∙Tenderness at lateral epicondyle ∙Pain upon gripping ∙Decreased grip strength ∙Increased pain with wrist flexion
What are 3 overuse disorders of the shoulder?
∙Tendinitis ∙Bursitis ∙Thoracic Outlet Syndrome
What are some common disorders of the hand and wrist that are seen in the workplace?
∙Tendinitis ∙Tenosynovitis ∙Stenosing Tenovaginitis "Trigger Finger" ∙DeQuervain's Disease ∙Carpal Tunnel Syndrome ∙Raynaud's Disease "Vibration White Finger"
What are some common examples of WRMSDs?
∙Tendinitis ∙Tenosynovitis (Inflammation of the tendon sheath) ∙Stenosing Tenovaginitis "Trigger Finger" ∙DeQuervain's Disease (Tendinitis of the thumb) ∙Carpal Tunnel Syndrome ∙Vibration White Finger (people who use vibrating hand tools, ex. drill, causes significant damage to nerves and capillaries in the hand and fingers go white) ∙Neck/back pain
Give a brief overview of medial epicondylitis.
∙Tendinitis of the common flexor origin, including pronator terms ∙Exacerbated by resisted wrist flexion and ulnar deviation, passive elbow and wrist extension in supination ∙Overuse syndrome seen in throwing sports
What are two disorders of the elbow?
∙Tennis elbow syndrome/lateral epicondylitis ∙Golfers elbow/medial epicondylitis
Who are the key people to include in an ergonomics evaluation?
∙The client (is it the injured worker, or is it the company?) ∙Management ∙Coworkers ∙Supervisors **Need informed consent from the people you are evaluating
How would you identify tasks in a hierarchical task description?
∙Use verbs ∙Motor cognitive and perceptual ∙Work with one task at a time ∙Identify all the related subtasks ∙Work with one subtask ∙Identify all related activities Stop when a discrete, measurable activity is reached
Where would you get information about injuries within a company when conducting an ergonomics assessment?
∙WCB Records: →Industry rating (Form 7 or 7A- safety records, gives info on number and cost of claims ∙First Aid Records →Vary according to company practices →Look for s/s for CTDs →Train first aid attendants to recognize CTDs ∙Individual Medical Records →Useful for return to work for individuals, not for benchmarking (private, ergonomists cannot get access)
What are the signs and symptoms of thoracic outlet syndrome?
∙Wide variety of symptoms depending on compression ∙Pain in fingers ∙Numbness in fingers ∙Weak pulse at wrist ∙Vascular forms are rare: s/s blanching, cold extremities
What are the guidelines for "safe angles" of the wrist to prevent WRMSD? The shoulder?
∙Wrist Flexion= <45° ∙Wrist Extension= <30° ∙Ulnar Deviation= <15° ∙Radial Deviation= <10° ∙Supination/Pronation= Minimal repetition Shoulder: ∙<30° abduction ∙<45° extension
