Setting Up Your Workstation

When adjusting your chair refer to any instructions that are provided with the chair or have someone show you how to adjust it and use the controls. If there is no one available to assist you, work through this checklist with another person and observe each other’s postures and body positions. Also, remember to try and avoid sitting for long periods of time. Some form of break from sitting every 20 to 30 minutes is helpful. Even getting up for 20 to 30 seconds to go to a printer or standing while talking on the telephone will provide some relief.

Seat

The chair height should be set so that the thighs are approximately horizontal and the feet rest comfortably on the floor (Fig. A.2).

• Combine chair and desk adjustments to position the work at elbow height. Where writing and mouse and keyboard tasks are performed, it may be necessary for the chair height to be adjusted slightly between these two tasks (that is, raised for keying or mouse work and lowered for writing).
• If the chair height is correctly set but the desk is too high, either lower the desk height or raise the height of the chair and use a footrest to make up the height difference.
• The backrest should be adjusted so that its convex curve fits into the curve of the lower back, centred about waist level. A slight backwards tilt of the backrest or forward tilt of the seat will allow an increase in the angle at the hip. This will decrease the force on the lumbar area.
• The thighs are wedged between the chair and the under surface of the desk, or the knees bump into the front of the desk then either the desk is too low, the chair is too high, the desktop is too thick or the user is too tall for the chair and desk. An ergonomist can give advice in this situation.
• Small adjustments can be made as often as changes in tasks to adopt the most appropriate posture for the task.

Back support

To adjust the height, start by raising the backrest to its maximum height and then sit in the chair and check the fit of the backrest to the curve of the lower back. If it’s not comfortable, lower the height by several centimetres and try this position (Fig. A.3). Repeat this adjustment and try each new position until the most comfortable fit is found. Ensure that the backrest supports the curve of your lower back and is not placed too low. To correct the forward/back position, adjust the backrest until a comfortable pressure is exerted on the lower back area while seated in the usual working posture at the desk.

The backrest position should not feel as though it pushes you out of the seat or that you have to lean back too far to reach it. There should be a twofinger clearance between the front of the chair and the back of the knee. Trial a number of different positions until the best fit is achieved. A slight backward tilt is a preferred position as the force on the lower back is reduced. Some people prefer to sit upright. You can vary this angle to provide changes in posture from time to time.

How to decide if you need a footrest

This will depend upon whether your desk is at the required height once you have adjusted your chair to suit your needs. If the desk is too high and it cannot be lowered, then raise the height of the chair and use a footrest to raise the height of the floor by the same amount. Footrests should have height and angle adjustability and be large enough to permit some movement while supporting the feet. A footrest should not be so big that it clashes with the chair base. Using a footrest limits mobility so it is preferable to have full adjustability of the desk and chair to avoid the need for a footrest.

Armrests

Armrests are designed to allow people to support themselves when getting up or sitting down. They are suitable for people who perform a variety of tasks at a workstation, move frequently to and from their chair or sit back in their chair to talk to visitors. Armrests are usually not recommended unless they are short, fit under the desk or are adjustable. However, if your chair has armrests make sure that they do not prevent you from getting as close to the desk as you require or that they impinge on your elbows while you are working. If this is the case, either remove them by unscrewing them, or replace them with a smaller or adjustable option (Fig. A.4)

Choosing between castors and glides

Castors allow chairs to be easily moved forwards and backwards, however, they are not suitable for use on non-carpeted surfaces unless fitted with friction brakes. Misuse of a chair with castors, such as standing on it, is hazardous. Glides or castors with friction brakes should be used where chairs do not need to be moved. For example, on a visitors’ chair or where hard floor surfaces exist. Care must be taken not to provide slippery mats at desks where chairs with castors are in use.

If you have a height-adjustable desk

Having first adjusted your chair to suit your body size, adjust the desk so the top surface is just below elbow height (Fig. A.5). To determine your elbow height, relax your shoulders and bend your elbows to about 90 degrees and check the elbow height against the desk height.

If you don’t have a height-adjustable desk

If the chair has been adjusted and the desk is higher or lower than the elbow, other forms of adjustment will be required. Start by measuring the height difference between the desk and your elbow.

If the desk is too high

Raise the chair by the measured difference and use a footrest. Set the footrest platform so that it is the same as the measured difference (Fig. A.5) or lower the desk by cutting the legs down by the measured difference.

If the desk is too low

Raise the height of the desk by extending the leg length or sitting it on wooden blocks or something similar. Remember to ensure that any such changes are secure and stable.

Clearance under the desk

General items, like computer hard disk drives, boxes of documents or files, rubbish bins and mobile drawers should not be stored under desks where they will decrease or interfere with the space required for the legs. This may force you to adopt a twisted or awkward posture of the spine (Figures A.6 and A.7).

Drawers

Most commonly used items should be placed in the top desk drawer to improve access and reduce reaching and bending movements. Where drawers are fitted to the desk, equipment such as the keyboard and computer screen should be arranged on the desk so that you can sit comfortably in the leg-well space.

Place trays at the outer reach sector (Fig. A.8). Intrays should not be located above shoulder level.

A variety of containers are available for mixed stationery items. These should also be stored at the outer reach sector (Fig. A.8) or in the top desk drawer.

Large or heavy references such as telephone directories and manuals should either be stored within close reach or in a nearby position where you need to stand to access them. Handling of these items should not be conducted at the limit of your reach capacity while sitting, as this can result in undue strain on the back, shoulder and arm muscles.

Angle

Tilt the keyboard using the feet at the back to suit your level of comfort. The common and preferred setting is where the feet are lowered so the keyboard sits flat on the desk. This assists in preventing awkward postures of the wrists.

Position on the desk

Place the keyboard as close to the front edge of the desk as is comfortable (Fig. A.8). Do not place documents between the keyboard and the front edge of the desk while using the keyboard as this increases the reach distance to the keyboard and may result in excessive bending of the neck to look at the documents. Ensure that there is room to put the keyboard to one side when it is not in use.

Place the mouse mat directly beside the end of the keyboard on your preferred side. Use the mouse in this position and always aim to keep the mouse on the mat during use. If you frequently use the mouse in your work you may wish to:

• learn to use it with both hands so that you can swap between the right and left sides for improved comfort;
• set the tracking speed of the mouse to a setting that suits you;
• maintain your mouse to keep it in good working order (for example, keeping it clean inside); and
• where possible, try and avoid holding on to the mouse when not in use.

The screen should be positioned once the chair and desk heights have been established.

Height

The screen should be positioned so that the top of the screen is level with, or slightly lower than, your eyes when you are sitting upright (Fig. A.9). If the screen does not have a raising device such as a monitor stand, you may be able to use telephones books to raise the screen height on a temporary basis.

Distance from the eye

First place the screen so that it is approximately an arm’s length away from your usual seated position (Fig. A.9). Trial this position and if necessary move it further away or closer as required.

Positioning the screen

The screen should be placed so that it does not face windows, catching reflections from the windows, or have a window directly behind it causing glare from the window (Figures A.10 and A.11).

The position of the document holder depends on your need to view and reach the documents and the type of document holder that is used. For continuous or frequent data entry where the source document is observed more than, or the same amount as, the screen:

• place the screen slightly to one side so that the document holder is directly in front of the user (see Figure A.12); OR
• place the document holder in a similar position to the screen where it is slightly to one side and you look evenly between the two (see Figure A.13).

An A-frame style book rest that sits on top of the desk is the most practical and can be set at different angles. It is usually best placed so that it supports documents on an inclined angle between the keyboard and the screen (Fig. a.14).

A lever or swivel arm document holder suspends the document above the desk at eye level. Anchor it to the desk on either the left or right of the screen, according to your preference, and place it directly beside the screen. See page 34 for further information regarding document holders.

The telephone should be placed either within or at the limit of the optimum reach sector, depending on the amount of use (Fig. A.8). The placement should enable the user to operate the telephone without the need to move their trunk to grasp the handset or to operate the numeric and function buttons.

When making a lot of calls, it may be best to place the telephone on the same side as the dominant hand so that this hand can comfortably operate the numeric and function buttons. When mostly receiving calls, it may be more comfortable to place it on the non-dominant side. Learn and utilise the functions of your phone, such as redial and the storage of commonly used phone numbers, to improve the efficiency of its use. Also, where the phone is used very often or for prolonged periods, a headset should be used.

An angled board can improve neck comfort where a job involves a lot of reading and handwriting. It should be placed immediately in front of the user on top of the desk (Fig. A.15).