1 October 2013

ERGONOMICS - Common Problems in Office Ergonomics





Common Problems in Office Ergonomics


Monitor won't fit

Monitors are getting bigger. They are often too deep to fit on old workstations, if the work surface is backed up against a panel or wall. There are a few possibilities for dealing with this.
  1. Get a wider work surface; for large monitors, the worksurface should be at least 30" deep. (The related preventive approach: if new monitors are being purchased, make sure worksurfaces are wide enough, or if new workstations are being ordered be sure that they can accommodate future purchases of larger monitors.)
  2. Put the monitor in the corner, with a keyboard and chair oriented in the same direction. Some furniture companies now will cut out a piece of counter from the corner and attach it to a sliding mechanism, to create a drop-down keyboard tray.
  3. A monitor arm may be able to help, placing the monitor above the keyboard.
  4. If the problem is that there is not also enough room for the keyboard and monitor on the worksurface, an adjustable keyboard tray will remove the keyboard from the work surface.
  5. If the work worksurface is not backed up against a wall or panel, simply slide the monitor back, so the rear of the casing hangs over the back edge of the surface.

Twisted posture

Ideally, a computer user should place the chair, keyboard, and monitor in a straight line. Usually as a result of space limitations, operators place the monitor to one side so that the neck is twisted. Or they may position the keyboard tray at an angle to the chair. Keyboard trays are available with various degrees of swivel and different pivot points, that allow the keyboard to be rotated into a position in line with the operator and monitor. If the worker needs the space in the center of the desk to do non-computer work, a separate computer area is the best solution (such as an L desk, or a rolling computer platform. If that is not possible, due to space constraints, a retractable keyboard tray and a monitor on a monitor lift would allow the computer to be pushed out of the way when non-computer work is being done.

Bad Postures

The ideal basic posture is feet flat on the floor, knees at about 90 degrees (without pressure against the back of the leg), lower back supported and leaning slightly back, shoulders erect, head centered about the shoulders, arms close to the side, elbows at more than 90 degrees, and wrists straight. However, it is helpful to change positions over the course of the day, to change pressure points and promote blood flow; you should experiment with variations from this "ideal" posture. Furniture should be adjustable to allow ideal postures, and workers should know how to make these adjustments. A common problem is that the height of the lumbar support of the chair has never been adjusted and is too high or too low to give lower back support (where the curve of your back is). Keyboards should be at the right height (see above), allowing the operator to bring the stomach right up against the keyboard (sometimes long armrests prevent getting this close - smaller elbow rests are better). The mouse should be at roughly the same height and distance from the body as the keyboard.

Workpractices

Good workstation setup alone can't assure that you won't get symptoms of CTD. Good work practices also need to be observed. This includes problems such as crossing your legs under you on a chair, perching on the edge of your seat so there is no back support, constant tensing of muscles, and prolonged bad postures of any variety. It also includes not changing positions over the course of a day, and typing techniques (see "Poor Typing Technique" and "Bad Postures" elsewhere on the factsheet).

Environmental Factors

Other environmental factors can also combine with risk factors for CTD's. This can include excessive cold or heat (both are physical stressors and cold can affect circulation), or exposure to indoor air quality issues such as toxic substances or inadequate fresh air.

Wrong heights for table and chair

Table surfaces and chairs need to be at the right height for the user to place his/her feet flat on the ground, keep the elbow angle greater than 90 degree, and easily maintain straight wrists. To check your work surface heights in relation to the user, there is a free program available through the internet from the Department of Energy called ErgoEaser (http://www.hss.energy.gov/ergoeaser/download.html).

Monitor wrong height or distance

In general the top of your monitor should be at about eyebrow height. (This is not true for operators who use bifocals! In this case, the monitor height must be lower. Experiment with a height that allows you to easily see the screen through the lower lenses while keeping the head upright.) You can experiment with phone books or inexpensive plastic risers under it until you get a height that feels comfortable. There are also monitor lifts that attach to the edge of the table that allow you to adjust the height over the course of the day (good for shared workstations), or cheap plastic risers that you can also use for storage. In general the monitor should be about 18-24" from your eyes, but this varies substantially with individual preference and strength of glasses. A rule of thumb: bring the monitor close enough so you can easily read print while leaning back against the chair's lumbar support. This positioning reduces the tendency to lean forward as you get fatigued.

Glare

If you can see the image of a window or light in your screen, glare is probably making it harder for you to see the screen. This glare should be reduced or eliminated where possible. While some of the newer glare screens do help somewhat, they are expensive and not as effective as eliminating the source. This can mean window shades, or placing the monitor at a 90 degree angle to the window or other light source. For overhead lights, you can take out some of the bulbs to reduce overall lighting (some say the proper background lighting for computers is "a pleasant level of gloom"), or putting egg-crate baffles on lights to reduce side glare. Task lighting can be used for lighting copy or desk work. Many operators tend to tilt the monitor up. Move the screen to a vertical position; this will often eliminate glare from ceiling lights.

Computer cord not long enough

Sometimes the wires connecting monitors, keyboards, etc. are not long enough to position monitor, CPU and keyboard at the ideal location. Often, longer cords or extensions can be used (although there are sometimes problems with the signal degrading from a long cord). Alternately, sometimes the computer can be placed on top of the table, or a cable hole can be drilled through the desk surface or partition wall.

Bifocals

Using the lower part of bifocals during computer use often forces you to tilt your head back, resulting in neck and shoulder pain. One solution is to get new glasses (progressive lenses with the center set to the 18-24" focal distance for computer use, or a single lens that is just used while on the computer). Sometimes, lowering the monitor allows the operator to hold his/her head upright while viewing the monitor through the lower lenses.

Mouse won't fit near the keyboard

Many older keyboard trays don't have enough room side to side to fit a mouse right next to the keyboard. This is often a problem on desks that have been converted to computer use without enough room for a wide tray. As a result, operators must place the mouse far away on the desk surface, requiring a forward stretch. If there is enough room, you can get a larger tray or a tray with an attached mouse tray. If there is not enough room, consider a keyboard tray with a mouse tray that slides back under the keyboard tray when it is pushed back under the desk. There are also some trays with a "floating" mouse platform; the mouse sits on a bridge that usually sits over the number pad, but can be moved when needed. An inexpensive version can be made with a few pieces of clear plastic or bent sheet metal. Another possibility is a keyboard tray or keyboard that has an integrated mouse alternative, such as a finger-sensitive pad. Voice recognition or keyboard shortcuts can also be used to bring mouse use to a minimum.

Mouse falls off if keyboard tray is in negative tilt

Some mouse trays that attach to adjustable keyboard trays allow the mouse to slide off, especially when using negative tilt. Look for trays that have a backstop. You can glue a piece of foam to the back of the mouse tray, making your own backstop. Sometimes the mouse cord can be looped through or tied (with a wire twist) to a structure to keep it from falling. Alternate input devices such as trackballs, pens or glidepoints can also be used.

Keeping finger tensed on mouse

Some office workers have the habit of keeping the index finger is always "at the ready" to click the mouse. This static posture can stretch the tendons and cause finger and hand pain. Likewise, precision mouse movement often requires contraction of several opposing sets of muscles to maintain accuracy. Sometimes a contoured mouse can help relax the finger, but a solution will generally require consciously relaxing the finger, removing it from the mouse, and regularly taking rest breaks.

Left handed people

Yes, about 10% of the population is lefthanded, and this affects many aspects of workstation set-up. Mouse use is a particularly troubling area. A right-handed contoured mouse (often termed "ergonomic" because it tends to fit the hand better) is worse than a non-contoured mouse for a left-handed person. There are now some companies that make left-handed contoured mice. Some of the keyboard trays now allow the mouse platform to be moved easily from one side to the other. But in tight places the tray will have to be attached to the table somewhat to the right to allow for the mouse on the left. Some keyboards now have detachable number pads, which are very useful for lefties who do a lot of number entry. These are also available as a separate item. The telephone may need to be placed on the right side of the work station to allow writing with the left hand.

Wrists aren't straight

When the wrists aren't straight, tendons have to travel further around the angle and are pressed against wrist structures. Thisreduces the strength of the hands and fingers, tends to inflame the tendons, and can increase pressure in the carpal tunnel. This is true of both up-and-down and side-to-side wrist deviations. For up and down deviations, the keyboard needs to be at the proper height and tilt so that wrists are straight.The height of the tray should put the keyboard as close to the lap as possible, allowing an elbow angle greater than 90 degrees. A negative tilt of the keyboard (the back is lower than the front) assists in keeping the wrists straight. Ideally, the keyboard tray should be adjusted to the proper height after the chair is set to the right height (so that feet can be flat on the floor). If the keyboard cannot be adjusted, then the chair may have to be set up higher, with a footrest.
For side-to-side bending (which typically is more of a problem for people with wide shoulders or with very narrow keyboards, such as laptops), one of the split or bent keyboards may help. Other things to look for include armrests that are too far apart (which bring the elbows out), or resting your wrists on the desk or a wrist pad rather than having the whole forearm move to reach keys on the edge of the keyboard. Adjustable elbow supports and changes in typing technique can solve these problems.

Banging the knees on the keyboard tray

Some keyboard trays have attachments or adjustments that extend below the level of the tray, so that you bang your knee or rip your nylons when you move in or out. There is little that can be done to help this except avoiding that feature when purchasing trays.

Sharp surfaces

Sharp, unprotected edges on desks can compress the underside of the wrist causing problems with tendons, blood vessels or the median nerve. Ideally, adjust heights or use keyboard trays that are at proper heights and have soft padding where wrists rest. You should not continually rest wrists while typing, but rather let your arms float above the keyboard. This reduces wrist bending and excessive finger stretching. Only use wrist rests for pauses between typing activities. The adjustable elbow rests described above allow this "floating" forearm posture, by removing most of the arm weight from the shoulder.

"Anchoring" wrists on table or wrist rest and thus stretching fingers too far

If the hands are "anchored" to a wrist pad or arm rest, then you are likely to stretch your fingers more to reach keys, and thus twist your wrists more. A better idea is to keep your hands floating above the keyboard while typing, and to just rest your wrists every once in a while at pauses in typing.

Laptops

It is impossible to get a proper position while using a laptop: either the monitor will be too low, or the keyboard too high. Additionally, often the keyboard is small and the monitor can be difficult to read. Some improvements can be made by using either an external monitor and lowering the laptop, or by using an external keyboard and raising the laptop. Many laptops can be used with "docking stations"; these allow the use of the laptop's hard drive with a full size monitor and keyboard.

Cramped Space

Many offices are being compressed into smaller spaces, which tends to create problems with setting up computers properly. In addition to the obvious solution of more space, efficient use of the space can help. Monitor lifts give additional desk space under the monitor and can thus allow non-twisted posture. Reducing clutter under desks on a continuing basis can also help (since accumulated clutter forces the operator to sit farther away from the desk). Putting the computer CPU vertically on the floor or in a CPU caddy under the desk can free up desk space. Sometimes printers can be moved away from the immediate area (which also creates a reason to get up and move around on a regular basis to pick up print jobs). Experimenting with different set-ups using phone books and other home-made solutions can reduce crowding.

No back support

There is no acceptable substitute for a good chair that is properly adjusted. Pillows that attach to chair backs with straps or Velcro that can provide temporary lower back support. Experiment with the back of the chair set to different heights. You may find yourself leaning away from the back support due to other workstation deficiencies, for example:
  1. the chair is so high that your feet are dangling off the floor,
  2. the monitor is too far away or small,
  3. glare makes the screen difficult to see-the tilt or height of the lumbar support is not set correctly.
Ask a co-worker to observe your posture over the course of the day to see how you are sitting.

No elbow support

There are differing opinions on the use of armrests: they are useful in giving support to the shoulders, but they can discourage you from moving your whole forearm while typing, causing you to twist your wrists more. A hard armrest can also put pressure on the elbow and compress the ulnar nerve. Long armrests can prevent you from pulling in close to the keyboard, which can result in long reaches. Non-adjustable armrests can result in your shoulders drooping too low or being pushed up. Or they may place your arms out too much to the side, thus increasing twisting of the wrist. Newer, padded elbow rests that are adjustable both horizontally and vertically give the best shoulder support. Sometimes these can be purchased separately to replace the older style armrests (or no armrests) on otherwise good chairs. It is also possible, in single-user chairs with fixed armrests that are too low and far apart, to wrap them with foam, thus bringing the armrest surface closer to the body and higher.

Improperly sized chair

A properly sized chair that is adjusted correctly is one of the most essential pieces of equipment. It should allow the feet to be flat on the floor, provide good lower back support, be adjustable so that positions can be changed over the course of the day (or for multiple users or multiple uses). It should not push against the back of the knee (proper pan depth and curved front), be adequately padded, and have adjustable elbow supports.

Big & small people

Most furniture is designed to accommodate about 95% of the population. This means that 5 people in 100 are too large or too small for typical furniture. This is particularly true of chairs and table heights. Some chair manufacturers make "papa bear" and "baby bear" chairs that that are designed to fit larger and smaller workers. Most table heights in modular panel systems are adjustable on a semi-permanent basis. Tall people can also be accommodated through putting blocks under tables to raise them up an inch or two. The ErgoEaser computer program (see above) can help in deciding on heights and angles of office furniture.

Elbows on hard arm rests or desk surface

Having the elbows on hard surfaces can put pressure on the ulnar nerve (well known as your "funny bone") which passes around your elbow. Proper height keyboard trays and mouse can reduce this, as can padding on arm or elbow rests (even some additional foam rubber padding put on with duct tape, while not pretty, can be effective).

Cradling the phone while using the computer

Cradling the phone between ear and shoulder to free up the hands for other activities is very likely to lead to neck and shoulder pain. The foam pads that attach to handsets help a little bit, but by far the best solution is a headset. In addition to eliminating the neck problems, these also help increase productivity since they make it easy to use the computer, pull files, or move around while on the phone.

Pulling files

Pulling files can be very stressful to the wrists and hands, since it requires a forceful pinch grip. This is especially true for tightly packed files. It should not be considered "light duty" for people who are restricted from other work due to Carpal Tunnel or other musculoskeletal disorders. There is additional stress if you have to reach for files in upper drawers where the wrist must be strongly bent while using a pinch grip. Solutions include cleaning out or storing less-used files to make them easier to pull out, and also putting the most used files in middle drawers.

Multiple users

Where more than one person is using a workstation, easy adjustability is crucial. This includes chair adjustments (seat height, back height and tilt, armrest height and width, pan depth, etc.), keyboard tray height, and monitor height. This is particularly important for people of very different sizes. Chairs in particular tend to present problems - sometimes two chairs can be set up (for two users), and swapped out (the second chair could be used for visiting guests).

Job stress

The highest levels of job stress are found in workers who have high work demands but low control over their jobs, especially if there is also low social support. Job stress is known to contribute to CTD's, as well as other problems, such as cardiovascular disease. There are some individual approaches to help reduce symptoms (exercise, meditation, mini-breaks) and also group solutions to try to prevent the problems through re-design of jobs and social relationships.

Not enough micro breaks

Constant work on a computer can lead to many problems. Micro breaks are brief task breaks where you get your hands off the keyboard and eyes off the monitor. This can include getting up to retrieve copies from the printer, stopping to make phone calls, stretching breaks, or other activities. They should be a minimum of 5 minutes an hour, but more frequent, shorter breaks are better. These are task breaks in which you perform other work activities, not "coffee breaks" (which should also be taken, but less frequently). Micro breaks tend to also improve productivity and concentration, as well as reduce stress on the hands and eyes. There is a variety of software and shareware that you can get to remind you to take these breaks, including some that give stretching exercises to do at the break.

Poor Typing Technique

Several typing techniques can lead to hand, arm, shoulder, and neck problems, particularly if in combination with improper computer set-up. This can include:
  • Keeping the little finger or thumb raised while typing (such as trying to not hit a key or spacebar by mistake when using cursor devices that are in the middle of the keyboard)
  • "Clacking" (hitting the keys hard)
  • Resting the wrists on the desk or wrist rest while typing
  • Inadequate breaks
Re-training can help with these problems. Lower strike force, letting the arms float above the keyboard while typing, relaxing fingers that are not being used, and reducing awkward stretches to far keys can all be helpful changes.

at

No comments:

Post a Comment