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reviewer in ergo and Qms, Summaries of Mathematics

Information and Communications Technology Academy (ICTA)Mathematics

reviewer in ergo and Qms. reviewer in ergo and Qms. reviewer in ergo and Qms. reviewer in ergo and Qms. reviewer in ergo and Qms

Typology: Summaries

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Reviewer in Ergonomics
ERGONOMICS
- Derived from two Greek words:
o “Nomoi” meaning natural laws
o “Ergon” meaning work
- Hence, ergonomists study human capabilities in relationship to work demands.
History
As early as 18th century doctors noted that workers who required to maintain body
positions for long periods of time developed musculoskeletal problems.
Within last 20 years research has clearly established connections between certain
job tasks and repetitive strain injury (RSI) or musculoskeletal disorders (MSD).
What two elements are at work?
1. Static Work
2. Force
Static work
- musculoskeletal effort required to hold a certain position, even a comfortable
one.
- Example: sit & work at computers; keeping head and torso upright requires
small or great amounts of static work depending on the efficiency of the body
positions we chose.
Force
- amount of tension our muscles generate
- Example: tilting your head forward or backward from a neutral, vertical
position quadruples the amount of force acting on your lower neck vertebrae
- Increased force is due to increase in muscular tension needed to support head
in a tilted position
3 Main Ergonomic Principles
1. Work activities should permit worker to adopt several different healthy and
safe postures.
2. Muscle forces should be done by the largest appropriate muscle groups
available
3. Work activities should be performed with joints at about mid-point of their
range of motion (ROM) esp. head, trunk, limbs
FACTS
- The average person working at a keyboard can perform 50,000 to 200,000
keystrokes a day
- Overexertion, falls & Repetitive Motion Injury RMI are the most common cause
of workplace injury
- An average of 125,000 back injuries due to improper lifting each year.
- Muscles overuse results in tiny tears in the muscles and scarring; these
contribute to inflammation and muscle stiffness
A Bit of Anatomy
- Overuse and small repetitive movements ie:
o cumulative trauma disorder (CTD)
o repetitive strain injury (RSI)
o Musculoskeletal disorders (MSD)
o Disturb balance of muscles, tendons, ligaments and nerves
- Brachial plexus
o a network of nerves in the shoulder that carries movement and
sensory signals from the spinal cord to the arms and hands. Brachial
plexus injuries typically stem from trauma to the neck, and can
cause pain, weakness and numbness in the arm and hand.
What causes Nerve Compression or Entrapment?
1. Repeated motions
2. Tight muscles
3. Inflammation of surrounding tissues
4. Misalignment of the nerve
What are 4 Common Nerve injuries?
I. Thoracic Outlet Syndrome
brachial plexus compression due to muscle tightness side of neck from poor
head position or slumped posture.
Signs & Symptoms: numbness, tingling in hand, made worse with overhead
activities or cradling phone between ear and shoulder.
NERVE INJURIES (CONT)
II. Radial tunnel syndrome
Compressed radial nerve at outside of elbow due to repetitive wrist and finger
extension or turning of forearm.
Signs & Symptoms: Sensations from elbow to base of thumb w ith wrist
weakness.
III. Cubital tunnel syndrome
Ulnar nerve compression inside of the elbow d/t repetitive bending of elbow
or resting your elbow on a hard surface
Signs & Symptoms : numbness or tingling and inside of arm with tingling to
ring & little fingers
IV. Carpal tunnel syndrome
compression of median nerve at level of carpal tunnel. Where is carpal tunnel?
Formed at wrist by ligament over the carpal bones in hand.
Signs & Symptoms : numbness or tingling in thumb, index, or middle finger &
½ of ring finger; often awakened at night by hand “falling asleep” Symptoms
increased by driving or attempting to hold objects; dropping objects is a
common complaint
Tendons and Tendonitis
Tendons
- are connective tissue that attach muscle to bone; have little stretch or rebound
- Tendon overuse, static or prolonged position = inflammation or tendonitis
- Tendons of wrist & hand very small; at high risk for injury with overuse
- “Tennis elbow” or lateral epicondylitis affects finger extensor tendons outside
of elbow
- “Golfer’s elbow” or medical epicondylitis affects finger flexor tendons inside
of elbow
What to do ??
a. Warm up & stretch before activities that are repetitive, static or prolonged.
b. Take frequent breaks from ANY sustained posture every 20-30 minutes.
c. Respect pain – positions or stop painful activity.
d. Recognize early signs of inflammatory process.
Maintain Neutral Posture
a. Maintain erect position of back & neck with shoulders relaxed.
b. Position equipment & work directly in front of and close to your major tasks.
c. Keep upper arms close to the body, elbows 90-100 degrees.
d. Keep feet flat on floor, upper body weight resting on “sits bones”.
e. Wrists as neutral as possible; safe zone for wrist movement is 15 degrees in all
directions
f. Avoid bending neck forward for prolonged periods of time
g. Avoid static positions for prolonged time; muscles fatigue → MOVE to
circulation!
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Reviewer in Ergonomics ERGONOMICS

  • Derived from two Greek words: o “Nomoi” meaning natural laws o “Ergon” meaning work
  • Hence, ergonomists study human capabilities in relationship to work demands. History As early as 18th century doctors noted that workers who required to maintain body positions for long periods of time developed musculoskeletal problems. Within last 20 years research has clearly established connections between certain job tasks and repetitive strain injury (RSI) or musculoskeletal disorders (MSD). What two elements are at work?

1. Static Work

2. Force

Static work

  • musculoskeletal effort required to hold a certain position, even a comfortable one.
  • Example: sit & work at computers; keeping head and torso upright requires small or great amounts of static work depending on the efficiency of the body positions we chose. Force
  • amount of tension our muscles generate
  • Example: tilting your head forward or backward from a neutral, vertical position quadruples the amount of force acting on your lower neck vertebrae
  • Increased force is due to increase in muscular tension needed to support head in a tilted position 3 Main Ergonomic Principles
  1. Work activities should permit worker to adopt several different healthy and safe postures.
  2. Muscle forces should be done by the largest appropriate muscle groups available
  3. Work activities should be performed with joints at about mid-point of their range of motion (ROM) esp. head, trunk, limbs

FACTS

  • The average person working at a keyboard can perform 50,000 to 200, keystrokes a day
  • Overexertion, falls & Repetitive Motion Injury RMI are the most common cause of workplace injury
  • An average of 125,000 back injuries due to improper lifting each year.
  • Muscles overuse results in tiny tears in the muscles and scarring; these contribute to inflammation and muscle stiffness A Bit of Anatomy
  • Overuse and small repetitive movements ie: o cumulative trauma disorder (CTD) o repetitive strain injury (RSI) o Musculoskeletal disorders (MSD) o Disturb balance of muscles, tendons, ligaments and nerves
  • Brachial plexus o a network of nerves in the shoulder that carries movement and sensory signals from the spinal cord to the arms and hands. Brachial plexus injuries typically stem from trauma to the neck, and can cause pain, weakness and numbness in the arm and hand. What causes Nerve Compression or Entrapment?
  1. Repeated motions
  2. Tight muscles
  3. Inflammation of surrounding tissues
  4. Misalignment of the nerve What are 4 Common Nerve injuries?

I. Thoracic Outlet Syndrome

brachial plexus compression due to muscle tightness side of neck from poor head position or slumped posture. Signs & Symptoms: numbness, tingling in hand, made worse with overhead activities or cradling phone between ear and shoulder. NERVE INJURIES (CONT)

II. Radial tunnel syndrome

Compressed radial nerve at outside of elbow due to repetitive wrist and finger extension or turning of forearm. Signs & Symptoms: Sensations from elbow to base of thumb with wrist weakness.

III. Cubital tunnel syndrome

Ulnar nerve compression inside of the elbow d/t repetitive bending of elbow or resting your elbow on a hard surface Signs & Symptoms : numbness or tingling and inside of arm with tingling to ring & little fingers

IV. Carpal tunnel syndrome

compression of median nerve at level of carpal tunnel. Where is carpal tunnel? Formed at wrist by ligament over the carpal bones in hand. Signs & Symptoms : numbness or tingling in thumb, index, or middle finger & ½ of ring finger; often awakened at night by hand “falling asleep” Symptoms increased by driving or attempting to hold objects; dropping objects is a common complaint Tendons and Tendonitis Tendons

  • are connective tissue that attach muscle to bone; have little stretch or rebound
  • Tendon overuse, static or prolonged position = inflammation or tendonitis
  • Tendons of wrist & hand very small; at high risk for injury with overuse
  • “Tennis elbow” or lateral epicondylitis affects finger extensor tendons outside of elbow
  • “Golfer’s elbow” or medical epicondylitis affects finger flexor tendons inside of elbow What to do ?? a. Warm up & stretch before activities that are repetitive, static or prolonged. b. Take frequent breaks from ANY sustained posture every 20-30 minutes. c. Respect pain – positions or stop painful activity. d. Recognize early signs of inflammatory process. Maintain Neutral Posture a. Maintain erect position of back & neck with shoulders relaxed. b. Position equipment & work directly in front of and close to your major tasks. c. Keep upper arms close to the body, elbows 90-100 degrees. d. Keep feet flat on floor, upper body weight resting on “sits bones”. e. Wrists as neutral as possible; safe zone for wrist movement is 15 degrees in all directions f. Avoid bending neck forward for prolonged periods of time g. Avoid static positions for prolonged time; muscles fatigue → MOVE to circulation!

Modify Tasks: a. Alternate activities frequently; rotate heavy &/or repetitive tasks with lighter less repetitive ones. b. If symptom become worse REASSESS task setup & look for alternative methods c. Avoid repetitive or prolonged grip activities d. Avoid pinching with wrist in flexion or wrist deviation (bending to side) e. Take frequent breaks to stretch & rest hands Body Mechanics

  • Use the largest joints & muscles to do the job
  • Use 2 hands to lift rather than one, even with light objects and tasks.
  • Avoid lifting with the forearm in full pronation (palm down) or supination (palm up).
  • Slide or push & pull objects instead of lifting.
  • Keep reaching to a minimum.
  • Carry objects close to body at waist level. Correct & Incorrect Techniques Lesson 2: Human factors and Ergonomics from the Earliest times to the Present Understanding Human Factors and Ergonomics The core knowledge of HFE describes:
  • How best to design tools
  • Machines in order to optimize these interactions and also the effect of the ambient environmental conditions when the interaction takes place. Compatibility: Matching Demands to Capabilities Compatibility between the user and the rest of the system can be achieved at a number of levels:
  • Biomechanical
  • Anatomical
  • Physiological
  • Behavioral
  • Cognitive levels Poor system functioning can be caused by a lack of compatibility in some or all of the interactions involving the human operator. This incompatibility can occur due to a variety of reasons. For example:
  • Human requirements for optimum system functioning were never considered at the design stage
  • Inappropriate task design
  • Lack of prototyping Brief History of Ergonomics Ergonomics came about as a response to the design and operational problems presented by technological advances in the twentieth century. It is a hybrid discipline that emerged when applied scientists came together to solve complex crossdisciplinary problems, and it owes its development to the same historical processes that gave rise to other disciplines such as industrial engineering and occupational medicine. The core sciences from which ergonomics is drawn are as follows:
  • Psychology
  • Anatomy
  • Physiology
  • Physics
  • Engineering Scientific management and Work Study Scientific management, developed by Taylor , and work study, developed by the Gilbreths, are pre-cursors of ergonomics. Both were developed at the beginning of the twentieth century and were based on the realization that productivity could be improved by redesigning the way work was done and not just by using better machines. Taylor (1911) was a mechanical engineer who is famous for his book, The Principles of Scientific Management. Taylorism had many advantages for management
  • Greater flexibility in allocating operators to easily learnt tasks.
  • Fewer skilled workers were needed. Skill shortages were avoided, and training costs and wages could be more easily contained.
  • Introduction of paced work enabled production schedules to be more rigorously quantified. Better predictions of output could be made.
  • If everyone worked at the same pace, the result was always a finished product. Human Relations and occupational psychology Occupational psychology developed in the 1920s and 1930s. The essence of Taylorism had been to regard the worker as an isolated individual whose output was determined by physical factors such as fatigue, poor job design, and economic incentives. A job would be redesigned to make it as simple as possible to learn and to perform. A production standard and rate of pay would be set and a bonus scheme introduced as an incentive for workers to produce more than the standard. Human Relations and occupational psychology Despite its advantages, Taylorism also presented management with a dilemma. Continually increasing productivity had to be met with continual increases in pay. To avoid this, new techniques were employed. New and higher production standards were introduced whenever sustained increases in output were achieved; bonuses only being paid when the new standard was exceeded. Hawthorne Experiments In the 1920s and early 1930s, a series of experiments were carried out over a period of 12 years by Elton Mayo and his colleagues at the Hawthorne Works of the Western Electric Company in the United States. The experiments are of historical interest more for their influence, which was to draw attention to social factors at work, than for their findings. The Hawthorne experiments earned their place in history, ushering in a new era of research into human relations in the workplace and drawing attention to the importance of social and personal determinants of worker behavior. However, the experiments themselves and their interpretation have always been controversial. Gillespie (1991) provides fascinating insights into the historical context of the Hawthorne experiments and the motives of the principal players, particularly Elton Mayo. Mayo had been impressed by the advances in industrial efficiency brought about by engineering and by the introduction of mass production methods. He had also been impressed by the work of Sigmund Freud, in particular Freud’s writings on the Psychopathology of Everyday Life, and had formed the opinion that uncooperative workers were suffering from a kind of psychopathology amenable to treatment. Hawthorne effect: The Hawthorne effect is a myth that is often mistaken for a fact. There is no standard definition. Sundstrom defined it as “the motivating effect of
  • The myth of post-Fordist management: work organization and employee discretion in seven countries
  • United States, Australia, Britain, Canada, Germany, Japan, and Sweden
  • Boreham concluded that there was scant evidence to suggest that truly participative organizational practices had been implemented in the countries studied.
  • Despite these reservations, participative practices have been accepted in some organizations and in some countries (e.g., Germany). According to Bernoux (1994), the requirements for effective participation are as follows:
  1. Employees have to acknowledge the need for participation.
  2. Employees have to trust that their participation will not have negative effects and that they will have some control over the final decisions.
  3. Employees have to perceive that changes are being introduced in a legitimate way.
  4. Employees believe that change is being implemented correctly.
  5. Employees have to be given a real role to play in the introduction and testing of new ways of working. The Fourth Industrial Revolution is the name given to the fusion of different technologies that started at the end of the twentieth century. Table 1.2 summarizes the key ingredients for successful participatory design of work equipment, according to Wilson and Morris (2004). Involvement Partnerships of stakeholders especially for development or use of standards Manufacturer involvement Trade Union involvement Driven by user and company needs Multidisciplinary Participation through all stages of design Commitment Commitment of all stakeholders Real support from senior management Someone to champion the process Clear perceived need for change Urgency Climate Appropriate knowledge levels among stakeholders Track record of success Acceptable industrial relations Open, communicative organization Management Clearly defined actors and roles Structured process that matches organization’s structure Clear, single, well-defined project Resources Clear identification of resource availability: time, money, equipment “Rich” information from real users Tools and Processes
  • Ergonomics is a broad subject, but there are two main classes of tools that span the entire discipline. These are;
  1. Ergonomics checklists
  2. Task analysis
  • To use a theatrical analogy, checklists are used to assess the design of the set upon which the performance takes place and task analysis is used to describe the performance of the actors General Ergonomics Checklist The general ergonomics checklist is used for the preliminary investigation of working conditions and is derived from a variety of sources: E. Grandjean’s original list, that of the International Ergonomics Association, defense standards, and other “mini” checklists that have appeared over the years. General Ergonomics Checklist
  • Job analysis
  • Work organization
  • Workspace design
  • Physical demands
  • Mental demands
  • Human–machine interaction
  • Work environment
  • Workforce characteristics
  • Job stress
  • Occupational background
  • Safety Task analysis Task analysis drives human-centered design by providing a system-specific context for the application of the fundamental ergonomics principles. The general procedure for carrying out a task analysis is as follows (Rasmussen 1983):
  1. Identify a prototypical task by collecting detailed descriptions from expert users of what different people do.
  2. Identify all the processes that comprise the activity.
  3. Analyze the descriptions in terms of the various options for action and the criteria used to select between them.
  4. Generate a prototypical task specification by selecting a characteristic set of tasks and specifying the work sequences common to them: ✓ Who must be involved? ✓ What are the subcomponents of the activity? ✓ How are participants involved in the various tasks? ✓ What information is required at each stage in the task? ✓ Where does the information come from? ✓ How is the information exchanged? ✓ How might any of the above be improved? The outcome of a task analysis consists of the following:
  5. Description of the behaviors required to carry out the task
  6. Description of the system states that occur when the task is carried out
  7. Mapping of the task behaviors onto the system states

Task analysis must not be allowed to become too complicated, and there are two main ways of ensuring that it does not: Decide, first of all on the boundaries of the task. When does it begin and when does it end? Think hierarchically but do not go into too much detail in the early stages. Begin by analyzing the task from the beginning all the way to the end at a high level (i.e., at the simplest level first, before going into detail). Do not go into more detail than you need to make the assessment. Mapping Elements

  • Indications and when to do the task
  • Control objects and operation
  • Precautions: valves in open position and hose secured
  • Feedback modality and indication of response adequacy
  • Fault diagnosis and maintenance Status of Risk Assessment and Design Tools The ergonomist’s toolkit is expanding rapidly with the development of tools for carrying out risk assessments and design activities.
  1. Validity : Does the tool measure what it is supposed to measure?
  2. Reliability : Does the tool give the same result when applied to the same problem under the same circumstances?
  3. Sensitivity : Is the tool able to resolve differences of the size that occur in the real situation or that are important in determining real outcomes?
  4. Diagnosticity : Is the tool sufficiently detailed to provide information about the reasons why one situation is different from another?
  5. Intrusiveness : Can the tool be used without disrupting the process that it is designed to assess?
  6. Acceptability : Is the tool acceptable for general use?
  7. Assessment of costs: The real costs both financial and in terms of human resources and disruption to normal operations should be reasonable in relation to the value of the information provided. SYSTEMS INTEGRATION
  8. efficacy
  9. effectiveness
  10. efficiency

WHAT IS COST-BENEFITS MODELS AND METHODS?

WHAT IS OXENBURGG PRODUCTIVITY MODEL?

Prevention is Better Than Cure

  1. Measure is inexpensive and only has to be applied once
  2. Incidence of the problem is high
  3. Cost of dealing with it is high
  4. Measure is effective in preventing the problem and has few side effects Examples of Industrial Ergonomics Programs

SUMMARY

  • HFE occupies the no man’s land between engineering and medicine, architecture, health and safety, computer science, and consumer product design. It is the only scientific subject that focuses specifically on the interaction between people and machines.
  • Historically, HFE can be seen to have arisen as a response to the need for rapid design of complex systems. The modern ergonomist has an important role to play as a member of the design team, providing scientific information about personnel (a scarce commodity in many organizations), an ensuring that all aspects of the system are evaluated from the users’ or operators’ point of view. Many tools are now available for the systematic analysis and specification of system ergonomics. The participatory approach seems to be the best way to ensure that the implementation of ergonomics will be effective. Further guidance can be found in ISO/TC 159/SC 1 General Ergonomics Principles. Lesson 3: THE BODY AS A MECHANICAL SYSTEM ANATOMY
  • Comes from the Greek words o “ana” which means up o “tome” which means a cutting.
  • Etymologically speaking, it means “the cutting up of a body” or simply “dissection”. Two Parts of Anatomy
  1. Macroscopic Anatomy is the study of large body structures. Surface anatomy is the study of external anatomical features without dissection. Regional anatomy focuses on specific external and internal regions of the body (such as the head or chest) and how different systems work together in that region. Systemic anatomy focuses on the anatomy of different organ systems, such as the respiratory or nervous system.
  2. Microscopic Anatomy - is the study of very small structures that cannot be seen with the naked eye. Cytology - the study of the structure and function of cells. Histology - the study of the organization and details of biological tissues
  • It connects to the pelvis and bears most of your body’s weight, as well as the stress of lifting and carrying items.
  • The lumbar spine bends inward to create a C-shaped lordotic curve. SACRUM
  • This triangle-shaped bone connects to the hips. The sacrum and hip bones form a ring called the pelvic girdle. COCCYX (TAILBONE)
  • Four fused vertebrae make up this small piece of bone found at the bottom of the spine. Pelvic floor muscles and ligaments attach to the coccyx. THE PELVIS
  • The pelvis has many different functions, with primary functions including structural support and stability for movement including standing, walking, and running to name a few of many.
  • The different structures of the pelvis allow for a variety of functions specific to that substructure of the pelvis. TWO PARTS OF PELVIS
  1. ANTERIOR PART
  2. POSTERIOR PART ANTERIOR PART The anterior part is called the pelvic girdle which is composed of the pubis, the ischium, and the ilium. It is connected posteriorly to the pelvic spine.
  • The pubic bone, the ischial bone, and the iliac bone join together on each side and are called the innominate bones. POSTERIOR PART
  • The sacrum forms the posterior part of the pelvis, and is made up of fused vertebrae.
  • Many primates have a tail extending from the end of the sacrum. SOME ASPECTS OF MUSCLE FUNCTION
  • The function of skeletal muscle is to exert tension between the bony points to which they are attatched
  • Tension is exerted when a muscle changes from its resting to its active state in response to impulses from the central nervous system. Muscle contraction
  • the physiological active state of the muscle, rather than its physical shortening. Two types:
  1. Static or Isometric Contraction
  2. Dynamic or Isotonic Contraction BACK PAIN MUSCLE STRAIN/SPRAIN
  • Muscle strains and sprains are perhaps the most common causes of back pain, especially in the lower back.
  • A strain refers to tearing of a muscle or a tendon (a fibrous tissue that connects muscle to bone), while a sprain refers to tearing of a ligament. SPINE OSTEOARTHRITIS
  • Osteoarthritis can affect any joint in the body, including the small joints of the spine (called vertebral or facet joints).
  • Spine osteoarthritis occurs as a result of "wear and tear" of the cartilage located between the spine's joints BULGING AND RUPTURED DISC
  • Over time, the bulging disc (without treatment) can eventually tear. When a disc tears, its inner content (nucleus pulposus) is released, which compresses nearby nerve roots or the spinal cord itself.
  • A torn disc is called a ruptured disc or a herniated disc. SPINAL STENOSIS
  • Spinal stenosis causes back pain in the aging population.
  • As you get older, the spinal canal gradually becomes constricted or narrowed, due in part to osteoarthritis and the thickening of tissues in your spine. Stress (posture) POSTURAL STRESS
  • Refers to the mechanical load on body by virtue of its posture (the average orientation of the body parts, with respect to each other, overtime). TASK-INDUCED STRESS
  • Refers to the results from the performance of the task itself (i.e. repetitive movement of wrist or fingers).

POSTURE

  • Is defined as the orientation of the body and its parts in relation to each other.
  • Has considerable influence on a person’s ability to exert force.
  • Affects the length-tension relationship. STATIC STRENGTH
  • Refers to the maximum steady forces or torque which an individual can exert in static exertion of short duration (3-5 seconds).
  • Also known as “maximum voluntary contraction.” STATIC STRENGTH
  • Factors that influence strength:
  1. Age
  2. Sex
  3. Training
  4. Motivation
  5. Medical condition DYNAMIC STRENGTH
  • Unlike static strength, it is difficult to define due to the following factors: **1. Acceleration
  1. Velocity
  2. Impulse movement**
  • Can be measured under 2 conditions:
  1. Constant velocity (using isokinetic devices)
  2. Constant force (where force is kept constant Lifting LIFTING STAGES
  3. Preparation
  4. Lifting
  5. Carrying
  6. Setting Down

IMPORTANT THINGS TO REMEMBER IN LIFTING

  • Use mechanical means (e.g. hand trucks, pushcarts, etc.) when possible for heavier or awkward loads.
  • Remember to obtain training and authorization before using a forklift.
  • It is easier and safer to push than pull.
  • Keep loads as close to the body as possible and do not twist while lifting, carrying, or setting down a load. Nose, shoulders, hips, and toes should all be facing the same direction.
  • As a general rule, bend at the knees, not the hips.
  • Get help when needed. Do not lift things you don’t feel comfortable with.
  • Plan ahead for all parts of the lift: lifting, carrying, and setting down.
  • Try to utilized proper handholds while lifting. If an item does not have a good handhold, think of ways to remedy this, such as placing the item in a container with good handholds, creating a safe and proper handhold with an appropriate tool, etc.
  • Use personal protective equipment where needed.
  • Implement rest breaks and job rotation for frequent and/or heavy lifting.
  • Place items to be lifted within the power zone. The power zone is close to the body, between the midthigh and mid-chest of the person doing lifting.