Computer Workstation - Ergonomics for Mouse Users Andrew Drewczynski Canadian Centre for Occupational Health and Safety This topic has been prompted by numerous questions addressed to the CCOHS’ Inquiry Service. Many inquirers, not only from all over Canada but also from abroad, express concerns regarding the health hazards involved in using a computer mouse on a regular basis. They ask for recommendations on how to eliminate the risk for injury that may result from overuse. Suggestions and solutions are based mostly on CCOHS’ in-house experience and first-hand knowledge. www.ccohs.ca

Common questions about using a computer mouse What can I do to avoid discomfort and/or MS problems while using a computer keyboard along with the mouse? What is the best (or perfect) position for the computer mouse? www.ccohs.ca/events/iapa2001

What is Ergonomics? Ergonomics is the discipline that matches the job to the worker and product to the user. A proper understanding of ergonomics is critical. “Matches” is the key word. It means that ergonomics is process, not a product. “Job” encompasses a few components: (1) the workstation's physical shape and size, (2) the design of the tools, equipment and machinery to be used, (3) the environmental conditions Job content: tasks -- their variety and sequence, work- and rest-breaks Worker: skills, work practices, work habits, worker’s active input To achieve a “perfect”, or at the very least, acceptable match, all these components must be considered.

You and Your Workstation fatigue First things first – the quality of a computer workstation cannot be compromised. www.ccohs.ca/oshanswers/ergonomics/office/

Standard Layout Here is a standard layout, with the mouse at one side of the keyboard.

Mouse – What it Does In order to operate the mouse while typing, the operator is frequently forced to reach forward or sideways, or even both at the same time.

Mouse – Common Complaints The main complaint is pain in the neck and shoulder region. This is due to reaching forwards and sideways. Repetitive movements are not so much to blame; rather it is the effort of holding one's arm with little or no support, often in an unnatural position, for a long time. Therefore our focus must be on eliminating or at least reducing the need to place one's forearm and hand to the side of the keyboard.

Mouse Platform Advantages of this platform: Reduces side- and forward movements Reduces the overall area of mouse operation Disadvantages: The mouse is located slightly higher then the keyboard – this defect can be alleviated by using a slightly higher arm support.

Mouse Platform Notice that reaching forwards and sideways is substantially reduced.

Keyboard with a Touch Pad Here is a keyboard with a touch pad for those applications that don’t require frequent and precise placement of the cursor.

Keyboard with a Touch Pad

Short Keyboard A narrower keyboard (14”) allows one to operate the mouse without side movements. A cordless mouse further minimizes discomfort, as one is not fighting a tangled cord all the time. The minor disadvantage of having to adjust to a slightly different key arrangement is well counterbalanced by substantially increased comfort.

Where Else Can You Keep the Mouse? Placing the mouse between the operator and the keyboard requires using cordless mouse. Individuals with shorter arms (and those who cannot get closer to the desk) may not benefit from such an arrangement.

Where Else Can You Keep the Mouse?

Proof-Reading Here's a solution for proof-reading thick and heavy documents.

We recommend that you separate typing tasks and mousing tasks. The use of function keys is very much recommended.