|To use different muscles and to reduce awkward postures of the arms or hands during mousing and to enable a relaxed hand position. The main target postures are deviation (sideways bending at the wrist) or pronation (working with palms facing the floor).
A number of ergonomic mice aim to place the hand and arm in the thumbs-up handshake position.
|Possible Drawbacks or Misuse:
|Some users find it difficult to adapt to new mouse shapes or mouse alternatives. Error rates sometimes increase and pointing speed and precision can slow. Most typists eventually return to their original accuracy and speed. Some of the more upright mice feel less precise when moving the cursor. Users may find making small adjustments to images or targeting small radio buttons more difficult.
Some alternative devices including some trackballs use thumb motions frequently that can tire the thumb or cause tendinitis.
Over-use of the mouse is strongly associated with an increased risk of hand & arm discomfort. An ergonomic mouse can help, but there is no evidence (yet) that ergonomic mice, trackballs, etc. are healthier or unhealthier than traditional mice. The main problem is overuse regardless of the kind of device. The best approach may be to switch back and forth frequently from one kind of pointing device to another.
|General End-User Instructions:
|Get used to alternative devices slowly. If discomfort develops, it may be due to the new design. Evaluate the situation carefully.
For pointing devices (mice, trackballs, styluses, touch pads), consider switching back and forth between different kinds of devices, rather than completely replacing one device with another. Some users also try switching between the dominant and non-dominant hand, but others find this very difficult.
Place the mouse at a comfortable height and angle relative to the user. Ensure that the user can freely move the arm and the mouse surface aligns with the forearm to enable a comfortably straight wrist.
Frequently release your grip and remove your hand from the mouse/ keyboard. Use keyboard shortcuts whenever possible. Keyboard shortcuts use fewer fingers and can be done with a relaxed wrist and finger posture. See the ErgoAdvocate Keyboard Shortcuts (pdf)
Consider adjusting the settings in the mouse control panel. You can increase the cursor speed for less movement or decrease the speed for more control. PC-based computers have a “snap to” feature that automatically places the cursor on the default button when opening a dialog box.
Below: Central Pointing Devices
Contour Track Bar
|For mouse alternatives there are a wide range of choices including:
- Central pointing devices
- Tablets/ Touch Pads
- Mouse pens
- Mice that use one finger
- Foot controlled mice
- Voice-activated inputs
- Plus a wide variety of mouse shapes and sizes
When choosing alternatives, evaluate whether the alternatives truly use different muscles, and make sure the mouse feels comfortable and fits your hand in a natural relaxed position. A poorly fitted input device can force your fingers into an unnatural splayed position which leads to strain. Follow the Goldilocks Principle; not too big, not too small, but just right.
Mice: many ergonomic mice are angled to limit hand and arm pronation (twisting the palm inward toward the floor). They come in various sizes and can have scroll wheels or buttons. Some mice are sculpted on both sides allowing use by left and right-handed individuals. Make sure the product you choose is comfortable and gives good control.
Trackballs are not inherently better than mice or other devices; however in some instances they offer a nice alternative. Trackballs can operate in a smaller space since only the ball on top needs to be moved – not the entire base. Many trackballs also utilize a thumb-button for the left click which can reduce the stress on the index finger which may be overworked in a traditional mouse.
Central Pointing Devices are mouse control devices placed between the user and the keyboard, rather than out to the side of the keyboard. Central pointing devices allow most users to work with the shoulders in a comfortable position in front of the body, and are preferred by many users with shoulder discomfort from reaching. There are several styles of central pointing devices including at least two brands that use a rolling bar to move the cursor, other varieties can include a touch pad, mini joystick, or centrally placed trackball.
Touch pads or tablets are generally small devices approximately 2X2 inches/ 5X5 cm. These are commonly installed in laptop computers, and are available as separate plug in devices for your computer. Like a trackball the touchpad takes up less space than the traditional mouse that needs room to run around. Touch pads can be placed centrally or to the side of the keyboard. Some users report less control with a touchpad, and the amount of moisture on your fingers may affect the control. Touch pads/ tablets are also available with a pen or stylus to move the cursor click buttons or even input text.
Other Alternative Input Devices: If you Google input devices or mouse you will see a number of additional results including these options; finger mouse, voice recognition software, foot control mouse, and visual recognition.
Having a variety of pointing devices available to users often produces the best results.