Ergo Keyboards

THE KEY TO KEYBOARDS

By Hayley Chandler

Are new keyboard designs the latest thing in ergonomics, or are they just the latest thing in gimmicks?

Most people would think that safety isn’t much of an issue in buying computer keyboards and mice. But well over a million Canadians use them regularly. There have been multi-million dollar lawsuits against keyboard manufacturers. And there’s an epidemic of lost-time claims related to carpal tunnel syndrome -- a painful condition of the hand and wrist related to repetitive motions combined with poor hand posture. This article is being typed on a keyboard which carries a permanent notice that reads, "Warning: To reduce risk of serious injury to hands, wrists and other joints, read the Safety and Comfort Guide."

So perhaps there’s something to it, after all.

People who spend most of their working time at computers are at risk of developing musculoskeletal injuries related to the classic ergonomic risk factors: posture, repetition and force. The most important of these factors in keyboarding -- the worker’s posture -- can be greatly influenced by the design of the equipment used.

That’s why some makers have completely redesigned their keyboards. "There are keyboard designs coming out now that claim to put your wrist into more of a neutral position or a better position," says Gillian Gibbs an ergonomist with BC Research Inc. in Vancouver, British Columbia. Scientific evidence about whether these alternative keyboards prevent musculoskeletal injuries is inconclusive. And determining which of the new designs will be most effective is a challenge.

"There are always new gimmicks," observes Geoff Wright, principal consultant for Ergonomics Plus, Inc. in Toronto, Ontario. "Some of them are improvements and some of them aren’t. It is very confusing for the consumer."

The Canadian Standards Association, in its standard CAN/CSA - 412-M89 Office Ergonomics focuses almost exclusively on posture for keyboarding and computer use generally. (It lists three standard keyboard designs and notes that "all these arrangements have been found satisfactory.")

When typing, "your hands, your wrists and your forearms should always be in a straight line," says Wright. (See diagram, page XX.) But you if focus only on these parts of the body, you might achieve a good position for the wrist at the expense of the proper angle at the elbow or shoulder. Consider how the entire arm is positioned. "If you look at home row on the keyboard, it should be just below your seated elbow height," says Kathy Kawaja, an ergonomics consultant for Human Factors North Inc. in Toronto, Ont. "Your upper arm should be relaxed at your side. Your forearm should be horizontal to the floor. So in other words, you have approximately 90 degrees at your elbow if we look at it from the side," she says.

Because standard keyboards slope upward, users often bend their hands upward at the wrist. They also tend to turn their hands outward, moving the baby finger toward the outside of the forearm. Users must also rotate their forearms so that their palms face the keyboard. "That’s why you see, in some of the keyboards, attempts to change both the angle and orientation of the keyboard," says Wright.

There are several different types of "alternative" keyboard designs available that all try to achieve better and more comfortable hand positioning.

Negative slope: Among the alternative designs available are keyboards with a negative slope or angle. The back of the board is lower than the front, so you can type without bending your wrist. "You’re lowering your fingers so you can maintain a straight line position between the hand, the wrist and the forearm," says Wright.

Split keyboards: Split keyboards are divided into two sections so that the distance between the left and right hand is increased. Many designs also angle or rotate each half of the board. The intention of both these features is to keep the wrist straight and to allow better positioning of the elbows and shoulders while keying. For some larger workers, the split keyboard is almost a necessity, says Kawaja. "The wider you are, the harder it is to get your elbows in," she says.

Tented keyboards: On tented designs, the keyboard is split and both sides tilt up toward the middle like a tent. This is to reduce rotation of the forearms. "Basically a handshake position is the ideal position that you want. It’s the most powerful position of the wrist," says Gibbs. With some models, users can adjust the angle of the tilt.

Keyboard trays: The keyboard tray that pulls out from under the desktop (and slides back out of the way when the computer is not being used) lowers the keyboard by two to three inches. This can improve the keyboarding posture, since desk tops are normally designed to be at the right height for writing with a pen, and are often too high for typing on a one- to two-inch high keyboard. Also, some of the fancier, "ergonomic" trays can be tilted back to achieve a negative angle with a standard keyboard.

Buying tips

If you’re purchasing an alternative keyboard, consider the following suggestions from the National Institute for Occupational Safety and Health (NIOSH) in the United States.

* Determine whether the keyboard is compatible with existing hardware and software and whether it can accommodate other input devices, such as mice. "Assess how the keyboard will fit with the workstation. Some designs are extra wide, long or high. As a result, they may not fit on standard keyboard trays or may prevent the tray from retracting under the work surface.

* Remember that some alternative designs make it difficult to see the keys, which makes it very difficult for "hunt and peck" typists.

* Check whether the job requires use of the numeric keypad and specialized keys because some alternative keyboards eliminate or reconfigure these keys.

* If the worker has symptoms of injury, a health professional should also be involved in the purchasing decision.

Keyboards often feature legs at the back, which you can flip up creating a positive slope. The average person assumes that is a good thing. In fact, the only purpose seems to be to make a keyboard profile more like that of a traditional typewriter. "Those legs at the back are completely useless," says Kawaja. "All they’re doing is increasing the profile and resulting in more wrist extension while you’re keying." A few designs feature flip-up legs under the front edge of the computer. If you use only these, you can adjust the keyboard to a slight negative tilt.

Another standard feature that has the potential to cause problems is the separate numeric keypad at the right of the keyboard. "It’s becoming increasingly difficult to find a keyboard where you don’t have the extended numeric keypad," observes Wright. The numeric pad makes the keyboard wider, which can create problems when you want to use a mouse. "Most people put the mouse on to the right, and so you actually have quite a reach with your right hand," says Wright. "One way to resolve that would be to not have a numeric keypad if you don’t use it for numeric functions."

Mice

Typing on a keyboard isn’t the only computer task that involves the risk factors for musculoskeletal injuries. "I’d say the mouse is probably one of the bigger problems at a computer work station in terms of introducing awkward postures and static work in your shoulders as well as repetitive clicking with the same finger," says Gillian Gibbs. (See "Advice on Mice", July/August 1996, page 50.)

"There are different sizes available now," says Gibbs. Make sure that workers have mice that fit their hands. "You shouldn’t have to spread your fingers really wide just to get your hand on the mouse and you shouldn’t have to move the index finger forward to click the key," says Kathy Kawaja. "No part of the mouse should be extending into the wrist area," she says.

If it’s too small, workers scrunch up their hands just to move the mouse and over-flex their fingers to click it. "You just want to be able to rest your hand on it and move it lightly," instructs Gibbs.

Left-handed workers may want to position the mouse on that side. You can buy a left-handed mouse, or, with symmetrical models, you can change the button assignment so that the index finger of the left hand clicks the primary button. (In the Windows operating system, you can find the mouse controls under the "Control Panel" menu.)

"The mouse should be at the same height as the keyboard for the same reasons because you want to have that same arm position," says Geoff Wright. It should be positioned as close to the keyboard as possible.

The consensus among the experts seems to be that it’s not the keyboard, but the way it’s set up, and the hand-arm posture it promotes, that make the biggest impact on user safety. So perhaps the best choice of keyboard is the one that the worker likes and is willing to set up properly. Plus, of course, there’s nothing wrong with trying out a gimmick or two.

Hayley Chandler is associate editor of safety purchasing for OHS CANADA.

BOX

DON’T CALL THEM WRIST RESTS

In health and safety circles, wrist rests have a bad reputation. "They are often misused," says Gillian Gibbs an ergonomist with BC Research Inc. in Vancouver, B.C. That misuse has lead to a lot of injuries -- and it may all stem from a very bad choice of names.

"It’s a very terrible name for the product," says Kathy Kawaja an ergonomics consultant for Human Factors North Inc. in Toronto, Ont. "The name implies that we rest our wrists while we’re keying when that’s the exact thing that we’re not supposed to do."

"The problem when you rest your wrists on a wrist rest while you’re keying is that you’re using the wrist rest as a crutch and the weight of the arms is distributed on to the wrist rest," she says. You don’t want to put pressure on the wrist because delicate nerves and tissues run through there. "If you rest your wrists while keying you have a high risk of getting tennis elbow," says Kawaja. The very small muscles of the forearm are doing much of the work to move the fingers and over time, they break down and become injured.

"You’re supposed to float your hands and arms over the keyboard," Kawaja says. "The movement comes from the large shoulder, chest and upper back muscles. They will not fatigue as quickly."

So what is the purpose of a wrist rest? It’s a place to rest the wrists when you’re not keying, Kawaja says. When the person is pausing, thinking, reading the screen, or interrupted by a colleague the wrists can go on a wrist rest.

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