Keyboard Design

The fundamental ergonomic risk factors that are typically present in a computer set up include: awkward postures, static positions and highly repetitive tasks. Methods of reducing these ergonomic risk factors with an office or computer set up involve maintaining neutral joint postures, alternating tasks, implementing stretch breaks and providing adjustability to the workstation set up. The keyboard is one of the primary components of the computer set up that can result in poor postures, static positions and highly repetitive tasks. The purpose of keyboard design is to promote neutral postures and reduce the strain on the working joints, muscles and tendons. By improving and promoting neutral arm, wrist and hand positions, computer related injuries can be prevented.

Alternative Keyboards
Alternative keyboards can help keep wrists straight and in a neutral position, thus reducing the stress and strain on the joints and muscle and tendon structures. Alternative keyboard designs include:

• Split keyboards: split keyboards are designed to promote a straight position of the wrist. This is accomplished by either separating the key pads and increasing the distance between the right and left hand sides or by tilting the keyboard pads away from one another.

• Tented keyboards: tented keyboards divide the right and left sided key pads and tilt them up like a tent. This position reduced forearm pronation.

• Built-in wrist rests: this feature helps provide additional support to the wrists and forearms; care must be taken to avoid excessive contact pressure onto the peripheral nerves.

• Sloped keyboards: traditional keyboard design uses a positive slope of the keyboard, meaning the back of the keyboard is higher than the front of the keyboard. A positive slope of a keyboard often causes excessive wrist extension and thus an increased pressure within the carpal tunnel and increased strain to the working tendons. By contrast, a negative slope or neutral slope, where the plane of the keyboard is either level or slightly higher in the front, often promotes a more neutral wrist position.

• Key position: the position of the keys is classified as straight, concave or curved. The various positions of the keys allow the fingers to work in a more neutral and relaxed position.

Guidelines for Evaluating Keyboard Design
The following guidelines can be helpful with keyboard selection:

• Verify that the keyboard is compatible with existing computer hardware and software.

• Make sure the individual keys are easy to depress. Additional effort on individual keys can increase effort and strain.

• Verify that the keyboard is compatible with the alternate input devices such as the mouse, pen tablet or trackball.

• Evaluate the workstation design to ensure the keyboard fits properly with the workstation and does not cause more severe or additional musculoskeletal stress or discomfort.

• Evaluate the posture and size of the keyboard user to ensure it is an appropriate fit.

• Assess whether the keyboard may affect the users performance or productivity.

• Verify that all necessary components are present on the keyboard. For example, not all alternative keyboard contain number pads, if the user requires a number pad, select the appropriate model.

• Allow the user to try several different models.

• Allow the user to try the keyboard on a trial basis.

• There is no one keyboard that fits all; a comprehensive ergonomics workstation evaluation is necessary to evaluate the individual workstation, keyboard user and postures.

• The ergonomic evaluator selecting the keyboard should be experienced and knowledgeable in ergonomics.

• Train the user on the proper use and maintenance of the keyboard, and instruct the user it may take several weeks to get used to a new design.

• Follow up with the Comprehensive Ergonomic Program and reassessment of the workstation to ensure worker safety and comfort.

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Can others share some experiences with alternate keyboards?!

Nicole Matoushek

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Nicole Matoushek, PT, MPH, CSHE, CE

ErgoRehab, Inc.

More information about ErgoRehab, Inc. courses

Other articles by Nichole:

Prompt Return to Work

Injury Prevention: The Shoulder Joint

Anthropometrics and Ergonomics

The History of Ergonomics

Why Offer Return-to-Work Programs?

What is Ergonomics?

Work Injury Prevention and Management

The Cost of Work Related Injuries

Ergonomics and Work Efficiency

Functional Outcomes in Worker Rehab

Conquering Barriers in Worker Rehab

Maximizing Reimbursement in Worker Rehab

Clinical Management in Worker Rehab

Work Injury Consultants

Marketing and Selling Ergonomics and Worker Rehab Services

The Economic Burden of Workplace Injuries

Keyboard Design

Health Ergonomic Objectives

Ergonomics: Work Design Principles

Ergonomics and Muscle Fatigue

Work Modifications using Administrative Controls