The typical reaction to a ringing phone is to pick it up to see if it is your mother, a telemarketer or an important business call. Ergonomics Professor Marvin Dainoff believes making or taking phone calls should trigger an additional reaction, especially for workers who spend most of their time sitting at a computer workstation.
"I stand up to talk on the phone," said Dainoff, Ph.D., CPE, director of the Center for Ergonomic Research at Miami University, Oxford, Ohio. "I have an advanced ergonomic work system that assures me a good working posture. But there's nothing quite like the benefits of movement. That's how the disks in the back get nutrients."
Dainoff's idea for giving workers a break from static postures is part of a growing trend in office ergonomics. Mom's advice to "Sit up straight" is giving way to a more flexible approach to seating and task performance. Experts are now emphasizing movement, mini-breaks from sitting, and postures ranging from backward tilt to forward tilt.
The phrase "The best posture is the next posture" is becoming a guiding philosophy in office ergonomics.
ANSI Standard
The American National Standard for Human Factors Engineering of Visual Display Terminal Workstations (ANSI/HFES 100-1988) sets the standard for office ergonomics and posture. The 90-page document includes design and equipment set-up criteria for everything from lighting and office furniture to computer keyboards and monitors.
Although the 1988 standard emphasized adjustability and flexibility, its cover illustration created the perception that an upright 90-degree sitting posture was the best posture, according to Dainoff, vice chair of the committee revising the standard. A revised standard will be released soon for public comment.
According to Dainoff, it will discuss four acceptable postures straight, forward tilt, backward tilt and standing and explain how to design tasks and equipment to support them.
Dainoff said, "One of the first orders of business for the committee was to put up [the upright 90-degree sitting posture] picture and say, "We cannot do this again." We didn't mean to say there was an ideal posture, but a lot of people took it that way." In fact, Dainoff said, a 90-degree posture is difficult to maintain and most workers do not sit back far enough to get back support in that posture.
A lot of computer users rely on a slight forward tilt because it brings them closer to the keyboard and monitor. It can put stress on the spine, however, unless the back is supported by the back rest and the arms by the arm rests.
A slight backward tilt is actually the most comfortable posture, according to several ergonomics consultants. Some experts even recommend as much as a 25-degree tilt past upright. A backward tilt, however, can make it hard for workers to reach the keyboard comfortably, keep feet flat on the floor, and see the computer monitor, said consultant Cindy Roth, a senior partner in Ergonomic Technologies Corp., Oyster Bay, N.Y.
There are pros and cons with many postures, and they have to be matched to the job tasks and work environment, Roth said. Only a few postures are inherently bad and should not be used even as alternatives to static postures. On Roth's list of postures to avoid are:
- Cradling the phone receiver between the chin and shoulder. Alternatives: Hold the phone in your hand or use a headset.
- Lifting heavy items from the floor, and moving or lifting office equipment while sitting. Alternatives: Stand up to move computer equipment, brief cases and anything else larger than a book.
- Twisting and reaching to get frequently used items such as the phone, note pad and reference materials. Alternatives: Place them within the normal range of motion, or, if they are used less frequently, move them far enough away so you have to stand up to get them.
"Posture is task-dependent," Dainoff said. "Whatever posture is being used has to be supported, and there should be enough variety in jobs so there are reasons to change posture." Dainoff said alternating among reading, writing and keyboarding activities, and walking to printers, copiers/FAX machines and file cabinets generally provide enough variety.
Adjustability
"Start with the chair" should be the rallying cry for companies interested in computer workstation ergonomics, according to Mike White, advanced applications manager for Zeeland, Mich., office furniture manufacturer Herman Miller.
"A decent chair is a necessity for trunk stability," added consultant Carole Hunter, president of Industrial Biomechanics, Piedmont, N.C., whose clients include Waterville, Ohio, chair manufacturer BioFit. "You can use a card table for a desk if you have a good chair."
What is a good chair? It has a waterfall-shaped front edge, supportive foam on the seat, and an adjustable seat pan and back support, according to Karla the Losen, marketing manager for office seating, Knoll Inc., East Greenville, Pa. She recommends that chairs have about 5 inches of seat height adjustability, a seat width of 20 to 21 inches, and adjustable arm rests.
Alcoa Corporate Ergonomist Sheila Krawczyk said the importance of arm rests is often overlooked. "Arm rests should be adjustable up and down, and in and out," she said. According to Krawczyk, arm rests should keep the forearms parallel to the floor, with the shoulders relaxed and the wrists in a neutral position.
They can be used for arm support during keyboard work, she said. Krawczyk does not recommend the use of wrist/palm rests because of concerns about increasing the internal pressure in the wrists.
Krawczyk is leading an ergonomics evaluation and education program to prepare 450 Alcoa employees to move into a new corporate headquarters next summer. The company is purchasing all new furniture, including three types of chairs and four workstation configurations. Besides adjustable chairs, the work areas will feature adjustable work surfaces, monitor stands, split-corner work surfaces that accommodate the keyboard tray and mouse, and indirect lighting. The equipment is designed to minimize back pain, neck strain, upper extremity discomfort and visual problems.
"Workers can't go wrong with any of these designs," she said. "With good equipment, training in how to adjust it and a motivated work force, we can prevent musculoskeletal discomfort and illnesses/injuries," Krawczyk said.
"Beyond Design"
Alcoa is spending a lot of money to improve office furniture, but Krawczyk is not stopping there. She believes strongly in training and encouraging workers to "alternate their tasks and postures throughout the day." Krawczyk said workers should add variety to their monotonous tasks with micro-breaks at least once every 15 minutes, where the task is varied or a brief rest taken.
Office ergonomics consultant Wesley Miles of Owasso, Okla., said that even customer service call center and data entry workers can change their postures without hurting their productivity. "Every phone call has an introductory sentence or two. Stand up for that and then sit back down when you need to use the computer," he advised.
Herman Miller's White said a good chair, with adjustable arm rests, allows workers to stretch and shift in their chairs. "Gross body movements" such as walking, standing or stretching are still the best tonic for aching backs, arms and hands, he said.
Miles said workers at all levels of an organization need to be trained how and why to adjust their chairs and workstations. That approach is more effective, he said, than mandating rest breaks, or telling workers that their chairs have been properly adjusted and they should not touch the controls.
"I have taught chair classes to Ph.D.s," said Miles, who worked for several major oil companies. "At first, I thought it was ridiculous, but they needed to know how to adjust their chairs. They"re smart people, and once they knew how to do it, they saw it was important."
Dainoff believes workers can compensate for "lousy" chairs and workstations by moving around and varying their tasks. The best solution, of course, is a combination of good design, worker training and flexible work practices.