Ergonomics

Risk factors

1) Repeated and sustained exertions -Pace, exposure 2)Forceful exertions -What part of the body, amt. of force, frequency, etc 3) Awkward postures 4) Contact stress 5)Tool Design 6) Noise 7) Vibration -Duration of exposure 8) Illumination 9) Temperature Hot/ Cold

keyboard angle

90 to 120

engineering controls

Equipment and workplace designs or changes that reduce human effort

office ergonomics

Holistic Client-centered ( increases compliance!) Worker size Tasks/work demands Worker habits

For the environment, remember:

Minimize Glare from windows and lights Maintain good air circulation Avoid sitting directly under air conditioning vents

What are MSD Signs and Symptoms?

Painful aching joints, muscles Pain, tingling or numbness Fingers or toes turning white Shooting or stabbing pains Swelling or inflammation Stiffness or difficulty moving Burning sensation Pain during the night

forceful exertions

are defined as lifting more than 25 pounds from a height below the knees or above the shoulders or at arm's length. Or 75 pounds at any one time; Pushing or pulling with more than 20 pounds of initial force

Safe, efficient job design is dependent upon, what?

coordination of all aspects of the system

seating

want it to be adjustable!! back (conform to natural curvature of spine) seat height- feet rest on floor seat angle armrest height- allow shoulders to relax Seat depth

Administrative controls

Changes in the nature of work: schedule, rotation, assignments of tasks

Job analysis

"Purpose is to reduce risk for injuries, reducing/slowing the progression of an injury or reducing the disability resulting from an injury" "Provides an objective basis for hiring, evaluating, training, accommodating and supervising persons with disabilities."

biomechanics

"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 activities"

neutral body positon

-Comfortable working posture where joints are naturally aligned -This reduces stress and strain on the muscles, tendons, and skeletal system and reduces your risk of developing a musculoskeletal disorder (MSD).

What does task anaylsis use?

-employer and employee interviews -Observation of multiple employees doing the job -Measurements of forces -Frequencies and duration -Postural requirements -Environmental -Psychosocial conditions

What does an evaluation include?

1) Personal Characteristics- cognitive, psychosocial -Medical History -Physical Activity Level -Strength Endurance 2) Understand the components/demands of the job tasks -Task analysis -Environmental Analysis -Physical Factors light, noise, vibration, temp, safety -Psychosocial job demands, pace, error rates, administrative support -Assess each task for risk factors (within the activity or job) -Identify the Risk factors and the Interventions -Generate a report/Assessment

Personal risk factors

Age, Gender, Hobbies, Previous Injuries, Physical or Medical Conditions, Pregnancy, Medications, Smoking and Fatigue

Ergonomic approaches

Altering movement patterns and use of proper joint and body mechanics -Distribute load over several joints -Use strongest, largest joints available for the task -Reduce force (slide verse lift) Restructuring activities -Work simplification -Altering the environment Using ergonomic equipment and assistive technology Activity pacing, planning, prioritizing and problem solving to modify activities and routines. -Balance activity w/ rest.

task analysis

Assessment of the physical, cognitive and psychological demands of the job. Interaction between the worker "by a detailed description of the human task requirements."

define essential task

Basic job duties accomplished with or without accommodation "Described as the reason the job exists and the degree of expertise or skill that is necessary to perform the task."

duration

Continuous exposure may not allow sufficient recovery time for muscles, tendons, and nerves, magnifies with other risk factors

job description

Defines the essential functions of the job Includes: -Essential job tasks -Physical and mental demands/requirements -Equipment/tools necessary -Work space -Environmental Conditions

When is force manifested?

Force is manifested from strong muscle contractions (demonstrate a bicep curl) my muscle is creating internal force. Or force is manifested as a strong physical exertion such as picking up a heavy load

force

Forceful exertions due to weight, friction, or posture can stress tissues (ex; muscles, tendons, ligaments) beyond their capacity, lead to fatigue and possible damage

Monitors

Front- 20- 40 inches away Top line of screen is at or below eye level Perpendicular to the window Flat monitors take up less space Corner units provide increased depth

good working positions

Hands, wrists, and forearms are straight, in-line and roughly parallel to the floor. Head is level, or bent slightly forward, forward facing, and balanced. Generally it is in-line with the torso. Shoulders are relaxed and upper arms hang normally at the side of the body. Elbows stay in close to the body and are bent between 90 and 120 degrees Feet are fully supported by the floor or a footrest may be used if the desk height is not adjustable. Back is fully supported with appropriate lumbar support when sitting vertical or leaning back slightly. Thighs and hips are supported by a well-padded seat and generally parallel to the floor. Knees are about the same height as the hips with the feet slightly forward.

DeQuervain's tenosynovitis

Inflammation of tendons thumb side of wrist Discomfort when turn wrist, grasp or make a fist Repetitive hand or wrist movements- gardening, music, knitting, cooking, lifting baby Treatment: immobilizing wrist and taking medications Possible surgery in serious cases. 4-6 weeks recovery immobilization

musculoskeletal injuries

Injuries & disorders (MSD) of the muscles, nerves, tendons, ligaments, joints, cartilage, and spinal disc. E.g. rotator cuff tendonitis & tension neck syndrome

CTD: (cumlative trauma disorder)

Injuries that occur over a period of time due to repeated trauma or exposure to a specific body part such as the back, hand, wrist and forearm. Muscle joints are stressed, tendons inflamed, nerves pinched or flow of blood restricted. E.g. CTS, tennis elbow, DeQuervian's Syndrome.

examples of repetition

Mouse limited movements to just a few fingers. Poorly designed stations require repeated reach to use the mouse/answer phone. Can fatigue shoulders and irritate tendons

sign and symptoms of injury

Numbness or burning sensation in hands Reduced grip strength in hands Swelling or stiffness in joints Pain in wrists, forearms, elbows, neck or back Blurred or double vision Itchy eyes Cramping or weakness

Why are MSD signs and symptoms important?

Once your employees are aware of ergonomics and risk they need to be able to identify signs and symptoms which are precursors to WMSDs. Early reporting can allow us to identify risk in the workplace and correct it before an employee is injured. Not all pain and discomfort may lead to injury- for example a physically demanding inventory task which only occurs annually. The worker has time to recover after inventory is complete, but the pain may indicate an opportunity for ergonomic improvements. But Pain and Discomfort are usually precursors to injury and should be considered warning signs or an indicator of a need for improvement.

repetition

Perform the same motions repeatedly at a fast pace and with little variation. Motions that are isolated and repeated for prolonged periods can cause injury

individual controls

Physical, cognitive, and social skills and performance of workers.

How to reduce repetition?

Properly arranging workstation and components. -Mouse close to keyboard -Maintain good posture/neutral position -Rest periods- micro breaks 5 min of each hour -Task rotation

Role of OT in ergonomics

Provide services for individuals and populations in various settings Design safe and efficient living environments, workplaces and products. Influenced by legislation mandating safe, accessible workplaces.

Finkelstein's test

Pull thumb with sharp ulnar deviation Pain is a positive sign for DeQuervain's Tenosynovitis

phalen's test

Pushing backs of hands together for 1 min. Compresses carpel tunnel Positive sign when same symptoms occur as with carpal tunnel syndrome

Goals of ergonomics

Reduce occupational injury Reduce workers compensation costs Improve work quality Reduce absenteeism Compliance with government regulations

Awkward postures

Static postures, or positions that a worker must hold for long periods of time, can restrict blood flow and damage muscles

define ergonomics

The study of how to fit work to the worker, "Fit the JOB to the PERSON", "The scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance"

People say that a hard days work never killed any one? It is good for you?

While a hard days work may not kill you it can cripple you. Fatigue at the end of the day is not necessary to show you worked hard- Work Smarter Not Harder!

Examples of how to change positions frequently?

Working in the same posture or sitting still for prolonged periods is not healthy. -Make small adjustments to your chair or backrest. -Stretch your fingers, hands, arms, and torso. -Stand up and walk around for a few minutes periodically.

compression or contact stress

a Concentrated force on a small surface area that reduces blood flow. One of the most common sources is when you have a sharp, hard desk edge creating a compressive force on the forearm. The forearm is a delicate area with nerves running close to the skin, compression of the forearm impedes nerve conduction. It is best to pad the edge of the work surface (as shown in the example) or to set the work surface to the correct height so the user doesn't need to rest his/her arms.

internal stress

occurs when a tendon, nerve, or blood vessel is stretched or bent around a bone or tendon

static posture

postures prevent the flow of blood which brings nutrients to the muscles and carries away waste products

neutral positons

promotes blood flow and gives us our greatest mechanical advantage but even a neutral posture can not be maintained all day

external contact

stress occurs when part of your body rubs against a component of the workstation, such as the chair seat pan or edge of the desk. Nerves may be irritated or blood vessels constricted as a result.

Lets say, for example, we go to the movies and have popcorn and pop. We take a seat and the movie beings. Demonstrate sitting in a chair. By the time the pre-views are finished we are sitting like this (demonstrate slumping in the chair). We unconsciously reposition our selves. Why?

the slumped position was uncomfortable, maybe even causing us some fatigue, so our natural defense system of our muscles told our brain to do something about it. Point: Fatigue can be a warning sigh to change what is causing the fatigue to avoid discomfort, pain and possible injury. Surly no one was ever injured in a movie theater