Think clicking, dragging and dropping are infinitely easier than typing? Think the graphic user interface is far superior to old-fashioned line entry? Not so fast. Sure, a desktop metaphor is intuitive, but is it safe? No, say ergonomics experts studying the use of computer mice.

There have been enough new repetitive stress injuries caused by mice that researchers and physicians have begun referring to the injuries as "mouse-arm syndrome." Experts say the price for ease of use has been sore arms, shoulders and necks. And as an alternative, they often suggest old-fashioned keyboard shortcuts.

Walk into any computer store's peripheral section, and you'll see countless "pointing devices" from companies claiming to have built a better mouse. Go to a trade show like Comdex and you'll be bombarded with strange new ways to point and click - the most unusual being the No-Hands Mouse, which you manipulate with your feet.

All of these are an indictment of the basic design of the original mouse, which forces a normal human hand into all kinds of contortions to scroll around Web pages.

The resulting injuries are costly, both to employers and employees. Estimates range from $10,000 to $40,000 per case. And just ask folks at IBM, Apple, Unisys, Honeywell, Digital, Compaq, Dell and KeyTronic about the costs of repetitive stress injuries. Those companies have all been named in lawsuits against keyboard manufacturers filed by carpal tunnel syndrome victims.

What goes wrong

Here's the problem: Using a mouse demands a small but constant tension on your hand. Combine that with an awkward position, do it eight hours a day for a year, and you can expect one of two things - pain in your shoulder and the back of your neck or inflammation in your lower arm and elbow.

The shoulder-neck pain is the result of reaching too far to use your mouse. For righties, it should rest as close to the number pad on the keyboard as possible, so your elbow stays comfortably bent while you mouse. As for the lower arm pain, that's often the result of gripping the mouse too tightly.

Think you don't do that? Imagine you're reading your e-mail at work - banging through, deleting some, firing off replies to others. While reading, many people sit in what Dr. Roberta Brackman calls "the readiness position." Mouse in tensed hand, waiting to pounce.

"Imagine you're just standing in the middle of the room, just standing there. It would get exhausting fast, much more exhausting than moving around the room," Brackman said.

Just how bad is it?

That's hard to say. A flood of studies is under way in places like the Ergonomic Technology Center at the University of Connecticut Health Center. Early returns say there's a serious problem, and researchers are starting to understand why. But there's no quantitative study to show how many mouse-related injuries there are.

The only authoritative study was published in 1995 by Liberty Mutual Insurance. The study covered only worker's compensation filings connected to mouse use from 1988-1993. Those claims doubled each year during that period, but the numbers are pretty small. The report's conclusion: "Although there are few claims related to computer mouse use, it appears to be a growing problem, and therefore, perhaps, deserves more research and intervention attention." The report also noted that women report suffering from mouse-related injuries more than men.

Without comprehensive national studies, we must rely on anecdotal evidence - and physicians in the field say cases of mouse-arm syndrome are rising sharply.

"Because nobody's bleeding, nothing is broken, it's easy to not deal with it," one told me. "That's a mistake."

Whose fault is it?

It's a combination of factors. Several experts interviewed for this piece said cases have spiked since the release of Microsoft's Windows 95 and Windows 95-based programs, which have many more mousing options than previous versions of Windows. (Microsoft is a partner in MSNBC.) For example, right-clicking was basically unheard of before Windows 95. On that list of experts is Emil Pascarelli, author of "Repetitive Strain Injury." But he doesn't blame the injuries on the software.

"For a long time, I felt the mouse had the potential to cause injury," he said. "I suppose it's coming to pass now.... There's probably an exponential rise related to increased use of the mouse."

But, he added, poor posture is the real culprit. People who were predisposed to getting injured using a keyboard because of their work habits or their workplace situation are also likely to be hurt using a mouse, he said. Education and treatment are the cure.

Not so, say other doctors. One told me flat out: "You can work with the keyboard, but the mouse has a major inherent design flaw. ... I think the mouse has been the culprit from the beginning."

What's the hardware problem?

You can tell by looking at the new mice on the market. Old mice, or cheap mice you might get buying a discount PC, are small, flat and square. Exactly the wrong shape. T

Better mice are larger, they basically mirror the image of a hand, and they have a hump in the middle to offer a place for the palm to rest. The goal, according to Steve Kaneko, design manager of Microsoft's Hardware Group, is to make mice "biomechanically neutral."

In the end, of course, the best any manufacturer can do is find a least-common denominator - model the mouse after the average hand, for example.

"What you really strive for in ergonomics is comfort," says Pascarelli. "And each person is different - ergonomics is a very personal thing." So there will be no universal hardware solution to this problem. WHAT'S WRONG WITH THE SOFTWARE?

The push for ease and simplicity guides all software development today. The "victory" of the graphic user interface released to the world with the Apple Macintosh has meant from the beginning a preference for clicking and dragging over typing. So more and more, users are steered toward mouse work. The Liberty Mutual study concluded that the mouse could account for up to two-thirds of computer operation time depending on the task performed and the software used.

And as for keyboard shortcuts - ever try to learn them? "Ctrl-Alt-F7" to print. Intuitive, eh? There's been almost no push to make keyboard shortcuts more obvious. That ought to change.

The Internet plays a part, too - scrolling is among the most demanding of mouse behaviors, and Web pages like this story are often "one long scroll."

"The software guys don't have a clue - they're adding more dragging, more pulldowns, more scrolling, " says Dave Rempel, an associate professor of medicine at the University of California, San Francisco.

At greatest risk:

Requiring fine detail work with the mouse is the biggest culprit - and so is software with "featuritis." Whereas the back button on Netscape Navigator or Internet Explorer is big and easy to hit, hitting dropdowns to change the color or font size in Word or many other word processors can be an exercise not only in frustration, but also in inflammation.

Likely victims include graphic designers, who use pointing devices in painstakingly delicate ways, usually applying great, and constant, force. Engineers and programmers are also at high risk for a mouse-related disorder, Rempel said.

"For people doing mouse-intensive work, it's a serious problem for them, and it's only going to get worse, because people's time on the computer only goes up," he said.

Brackman said most of her patients can point to some kind of change as the culprit - either there's new hardware, new software that has changed work habits, or a new workstation or desk. Then there's just plain, old-fashioned stress.

"There are psycho-social agents," said ergonomist Nick Warren. "As stress goes up, there's a correlation between that and the force [workers] put on a mouse - particularly doing very fine work. There's a tremendous amount of excess gripping."

What to do about it?