1. What is Ergonomics?
1.1 Ergonomics is the study of Human Factors Engineering
The term is derived from the Greek: Argo = labor and Nomos = law
Ergonomics is the study of the influence of the environment on productivity in the workplace; the evaluation and improvement of the interface between the individual and their work environment by correlating work conditions, instrumentation and tasks with the natural functioning of the individual in relation to their physical, mental and physiological fitness, so as to improve their convenience, health and efficiency at work.
Ergonomics implements theory, principles, data and the methods for designing the work stations and the environment, developing products, systems, tasks and assignments, so as to assure their compatibility and accessibility to users, in accordance with their capabilities, limitations and needs (compatibility 0f the environment to the individual and not the worker to the workplace).
Frequently, due to the ability of our body to adjust, we tend to fit ourselves to our environment rather than adjust the environment to us. With time, this might lead to accumulating physical trauma that will eventually manifest itself in pain and possible damage to the bones, muscles and nerve system in various places of the human body.
1.2 Accumulated Physical Trauma
Respective strain injury is defined as health disorders related to accumulating bio mechanical strains due to exposure to ergonomic risk factors in the work environment. Respective strain injuries (RSI) are most common at work, for instance: carpal tunnel syndrome: (CTS), a damage potentially caused to the median nerve of the wrist, which might impair the functioning of the hand and cause inflammation of the sinew (Tendonitis), muscular, neural and skeletal injury (MSD – Musculoskeletal Disorders) of the lower back, neck, shoulders, etc.
1.3 Risk Factors
These are physical risk factors such as improper posture at work, mechanical pressure, the extent of repetitiveness in motion, lack of movement and environmental risk factors such as light source, climate or noise. Exposure to these risk factors for an extended period of time may result in accumulating physical injuries.
1.4 Work Station Evaluation
Evaluation or review of the work station using an ergonomic labeling list aids in reducing ergonomic risk factors and potential physical injuries.
2. Ergonomic Principles for Appropriate Working Environments
2.1 Ergonomics in the Office
2.1.1. Sitting in front of the Computer
Adjust the height of the chair according to the height of the work station, ensuring that your hands are: at a 90 degrees angle, between arm and forearm, parallel to the table, and that your shoulders are relaxed and without strain.
Should your legs not reach the floor in this position, add a stool so as to allow a sitting posture in which your legs are supported, for more convenience.
Lean back on the chair in a 105 degrees angle. This will reduce pressure on your back. (Use the chair lever to change the angle of the back rest)
Adjust the height of the back rest of your chair for full support of the lower back (Use the chair lever to change the height of the back rest.)
Adjust the height of the computer screen until its upper edge is on the same level as your eyes. If the screen is low, its height should be adjusted. Another option is to raise the screen.
The optimal distance between your eyes and the screen should be that of the extended arm, i.e., between 60 to 70 cm.
The keyboard and the mouse should be placed side by side, 8 – 10 cm away from the edge of the table, to enable placement of the palms in a straight line with the mouse and the keyboard.
Make sure that your wrist is positioned straightly when typing and that your wrist is not bent.
The forearm should be supported by the table or by the arms of the chair.
Take regular intervals (5 minutes every hour) and perform stretch and relax exercises.
2.1.2. Movements to be avoided so as to prevent accumulated physical trauma
Avoid bending forward for an extended period of time. This might weaken the ligaments in the lower back and consequently cause lower back aches. Make sure you sit according to the ergonomic principles. (Clause 2.1.1).
Avoid extending your arm for too long. This will cause pressure on the arms, shoulders and neck. Make sure the most frequently used accessories are within reaching range, ideally up to 40 cm from your body.
Avoid bending or stretching your neck too much or for an extended period of time, i.e., over 15 degrees upwards or downwards. This might cause pressure on the neck and back. It is recommended that you raise or lower the screen, according to the ergonomic rules.
Avoid blocking the space around your legs with various objects. This might cause an improper sitting posture. See to it that the space around the legs is free for placing of the legs comfortably and vacant space is available for using a stool.
Avoid bending your wrists while typing. Sit properly and position a supporting pad under your wrist, according to the ergonomic principles.
Avoid bending your palm while operating the mouse, by adequate sitting posture: keeping elbows tight to the body and adding a supporting pad to the wrist.
2.1.3. Principles of Proper Sitting
Illustrations of proper and improper sitting positions , Advisable accessibility ranges – working with the computer:
2.2 Ergonomics in the Laboratory
2.2.1. Sitting/Standing
When working at high work surface in the office or laboratory, it is advisable to work both standing and sitting.
When sitting, the height of the back rest of chair should be adjusted to the height of the work surface - elbows parallel to work surface.
The back rest of your chair should support your lower back.
Use a proper laboratory chair with a ring that supports the soles of your feet.
Frequently used accessories are to be positioned up to 40 cm away.
Accessories seldomly used should be positioned 40 – 60 cm away.
Sufficient space is to be left at the feet to enable comfortable sitting posture.
If standing for an extended period of time, one foot should be placed in front of the other. Change this position frequently.
2.2.2. Lifting and carrying
If objects/bottles are placed high above, a stool should be used.
When lifting heavy objects, lower your knees in and place your feet in a stepping position, thus straightening your back while accomplishing the task.
When moving an object, carry it close to the body and, if necessary, use a cart.
2.2.3. Working with pipetors
When using pipetor, lift your arm parallel to your body.
It is advisable not to exert prolonged pressure which might cause extensive pressure on the thumb.
Pipetors should be placed within reasonable range for comfortable accessibility (between 40 – 60 cm).
When using pipetors for small volumes (micro liter) that requires preciseness, it is advisable to lift the Eppendorf test tube and avoid bending the head forward.
Make sure the pipetor is in order and comfortable to use.
Make sure the illumination intensity is comfortable. This will improve the quality of performance.
Take regular intervals during prolonged activity and stretch and relax your wrist.
2.2.4. Movements to be avoided so as to prevent accumulated physical trauma
Avoid standing with your back bent forward for an extended period of time, as this might overstretch ligaments in your back and, consequently, cause back aches.
Avoid repetitive postures that require exaggerated bending or stretching of the wrist.
Avoid postures that require elongated pressure with the hand. This might cause pressure on the synovium and cause pains when moving the thumb. (Strong and quick pressing is advisable.)
For More details:
http://www.weizmann.ac.il/safety/ergonomics.html
http://www.nismat.org/ptcor/ergo