v Comfortable size to fit your hand
v Don't hold mouse with thumb and little finger
v Speed of mouse clicking on screen should be adequate
v Speed of mouse moving on screen should be adequate
v Use a mouse pad
v Use a forearm rest
v Buttons should be angled
v Buttons should be easily pressed
v Mouse should be cleaned inside regularly

A good size and shape for a mouse is one that fits comfortably under your relaxed hand.

Correct positioning of hand to hold mouse

Cup your hand, then place your cupped hand and forearm on the table, face down. Completely relax your fingers, so that your whole arm is relaxed. As shown above this is the position your hand should be in when holding the mouse. This means that the mouse should be smaller than your hand, and quite low. It should be just big enough that the weight of palm rests on the mouse, the fingers should be relaxed with the middle finger resting on the mouse buttons. The buttons should not be so sensitive that resting the fingers on them causes them to depress.

The mouse should be moved using the weight of the palm. Don't actually "hold" onto the mouse with the fingers, especially avoid holding with the thumb and little finger. Ideally you should relax the fingers such that the thumb and little finger aren't even touching the sides of the mouse.

This position allows you to "hold" the mouse without any static muscle tension, simply by the weight of your hand. Many people squeeze or clench the mouse, perhaps scared that if they let go it will run away!

It is important to have plenty of room for the mouse. This is a common mistake with the mouse being placed at the edge of the desk. This allows no room to rest the forearm. The result is that the user rests the arm on the wrist at the edge of the table and pivots the mouse from the wrist.

Correct and incorrect placement of mouse

This is not good for the hand or wrist. As a guideline the mouse should be placed 20-30 cm into the work space (not just next to the keyboard), and should have plenty of room to move around. A forearm rest can be used for the mouse as well as the keyboard. Either use a separate one, or use a combined one, a forearm rest much larger than the keyboard.

The mousepad should ideally be raised to the level of the keyboard keys (or just below). This can only be done if a fore-arm rest is being used in which case use packing under the mouse pad to raise it.

With your fingers relaxed and resting lightly on the buttons you should be able to pull the button down. Think of pulling instead of pushing the button, and use the middle of each finger, instead of pushing with the end. Curved or slanting buttons placed towards the end instead of the top of the mouse are better.

Correct way to hold the mouse

Flat buttons on top tend to promote the curling of the fingers above the button. Instead of using the index finger on the main button, try using the middle finger. Your middle finger is the strongest and placing it on the main button puts your hand in a better position on the mouse.

As with the keyboard, pretend that you cannot move your wrist. Instead move the mouse from your shoulder and elbow. Pretend your forearm and hand are completely passive and must be pushed and pulled around by your upper arm. This approach ensures that you use the large fatigue resistant muscles in your shoulders and upper arm, instead of the tiny muscles in your hand and forearm.

This method takes some practice and may feel difficult at first, due to the coarser co-ordination of your arm muscles.

One of the main reasons for tension in the arm when using the mouse is the speed setting of the mouse. Many systems default to quite a high speed setting, meaning that the entire screen may be only 2cm wide on the mouse pad.

This is the size shown above. Imagine trying to select a button, position some text or draw an accurate diagram on a screen this size. As far as your mouse is concerned each screen pixel may be only 0.02 mm (20 millionths of a metre) across. It is advised that you remove any acceleration options, and choose one of the lowest speed settings. A good guideline is that your screen should be approximately ½ to 1/3 the size of your mouse pad, i.e. moving the mouse pointer from one side of the screen to the other means moving the mouse across ½ to 1/3 the width of the mouse pad.

This corresponds to a mouse screen of 10-15 cm wide (3½ times larger). This slowing of the mouse should help to force you to use your whole arm to move the mouse, instead of twisting the wrist and moving the fingers. Generally speaking the lower the mouse speed and acceleration the lower the stress on your arm.

From the Start menu on menu bar, choose Settings / Control Panel
In the Control Panel and double-click on the Mouse
Select the Motion Tab
Move the double-click speed slider to Slow

And

In the Control Panel and pointer-moving on the Mouse
Select the Motion Tab
Move the pointer-moving speed slider to Slow

Press OK

From the Start menu on menu bar, choose Settings / Control Panel
In the Control Panel and double-click on the Mouse
Select the Motion Tab
Move the double-click speed slider to Adequate

And

In the Control Panel and pointer-moving on the Mouse
Select the Motion Tab
Move the pointer-moving speed slider to Adequate

Press OK

Natural oils from your hands, combined with dust and dirt from the air will eventually collect on your mouse pad and inside the mouse. Eventually this will cause erratic operation of the mouse. Every couple of months or so you should clean the mouse pad and inside the mouse. Often these can contain thick layers of dirt.