Input devices

The ideal location:

The height of your keyboard should keep an "open angle" (greater than 90°) with your arms.

	For traditional desks this probably means raising your chair. They were not designed for keyboards.
	The keyboard should be just above the level of your lap. This is possibly lower than you might expect.
	It leaves your elbows at a comfortable angle and minimises the pressure on wrists and fingers. Your forearms should be roughly parallel to the floor.

After sorting out the height of the keyboard, examine the tilt of your keyboard.

	The aim is to keep your wrists in a neutral, (not bent up or down) relaxed position.
	Use the legs under most keyboards to tilt the back edge of the keyboard up or down. Use a thick ruler under the front edge to achieve negative keyboard tilt.
	The angle you adopt depends on the ergonomic curvature of the keys and the keyboard's distance from you.

Your shoulders should be relaxed.

	It is a tiring and ultimately stressful to raise your elbows with your shoulder muscles.
	To check your posture let your arms hang naturally then lift them to the keys to check the height is correct.
	You should not have to adjust to the height of the keyboard by hunching your shoulders.

Stay centred on the keyboard.

	Align yourself with the "B" key.
	Keyboards are not symmetrical. Most have a numeric keypad on the right. Unless you are doing your accounts, centre yourself in front of the letters.

But things are not always ideal:

	If you have a laptop, you are stuck with a flat, badly set out keyboard. The lap would probably be a better position to work on it from than a desktop.
	If you are not a touch typist, the location of the keyboard might be influenced by the need to have the keys at the same distance from your eyes as the screen.
	Body shape matters. If you have a broad chest, or have to work from a chair with armrests, consider a "split" keyboard where the two halves incline slightly outwards. This allows your arms to point inward conforming to the contours of your body.

Wrist rest is both a tongue-twister and a misnomer.

	It is probably your palms rather than the wrists that you will rest on any surface. See mousebean.com
	Neither part of your anatomy (writs or palm) should be in contact with the surface while typing.
	When you are using the mouse, a wrist wrest can help to keep your hand level with your arm. The temptation is to flex the wrist. Some people use the arm- rest of their chair to keep the hand and arm in a straight line. You should avoid this.
	Modern keyboard designs have a detachable skirt above, which your hands can float and rest on whenever you pause for thought.
	Aligning the keyboard with the edge of the desk ensures that the wrists 'float'.
	Repeated bending of your wrists up and down compresses the structures inside the carpal tunnel.
	It is good practice to rest your hands in your lap when you are not typing.

The standard 2 mouse button can be hard on the hand, arm and wrist if used for prolonged periods.

The drawback of the standard mouse is the space it needs to roam. Pushing the mouse about can be tiring.

An alternative is the tracker ball which is really an upside down mouse. You rotate the ball rather than pushing the mouse over a mat.

	The tracker ball takes less desk space
	It can be operated from any comfortable position as it does not need a flat space to 'roam'
	It often allows different fingers to be employed spreading the workload
	These devices often have better ergonomic design providing good support for the hand.

But the manufacturers have not yet started to make these in a range of sizes such as 'lumberjack' and 'brain surgeon'

	Don't bang on the keyboard. Employ a light touch even when angry or excited, as it wears out the keyboard and your fingers. (Epicondylitis).
	Don't use chair armrests while typing, only while resting.
	Keyboard need some maintenance otherwise you end up basing them.
	Keyboard shortcuts or macros can reduce repetitive tasks.

Health Hazards