Office chairs and productivity: Exploring the ergonomic link

Telemarketing, Feb 1994 by Fitzgerald, Stephen

Office environments are in a state of change. Gone are the days of purchasing office seating based primarily on how it would complement office decor. The modern office has evolved into a technological environment rich with computers -- and thus visual display terminals (VDTs) and keyboards -- which often require users to perform repetitive motion tasks. At the epicenter of this high-tech environment is the office chair.

Taskworkers, such as telemarketing representatives, who regularly use computers risk developing repetitive motion injuries (RMIs) as a result of repetitious, often forced movements typically involving the wrist or elbow. Similarly, old-fashioned back strain continues to take its toll on office and factory workers -- the "captive consumers" in our society. In fact, back-related injury is a leading cause of lost work time in the U.S. It is estimated that more than eight million new cases of work-related back injuries are reported by employees each year, accounting for 70 percent of all workers' compensation claims.

Legislation citing acceptable standards for the workplace has been enacted, and will continue to be passed at all levels of government to ensure that the human factors of doing business are not overlooked. The intent of these laws is to provide safe, ergonomically designed office environments that benefit both employees and employers. The city of San Francisco led the way by enacting an ordinance that governed the human factors associated with using visual display terminals (VDTs). This comprehensive legislation covered everything from the VDT itself to; and including, seating, worksurfaces, lighting and noise abatement; Although a Superior Court of California later overturned the ordinance, legislative bickering at all levels of government continues, and the U.S. Labor Department's Occupational Safety and Health Administration (OSHA) is presently considering various proposals.

So, how can an ergonomically designed chair help prevent potential workrelated injuries and productivity loss? First, let's take a look at the physical factors that impact worker fatigue.

How a person sits, also known as posture, is directly affected by the physical forces that work against it. When sitting in a chair, it requires energy to maintain the upright position. This energy is in the form of muscle activity. No one would argue that holding a weight at arm's length will eventually result in muscle fatigue, and ultimately the weight must be put down. Similarly, maintaining the upright position while seated eventually leads to muscle fatigue and loss of productivity.

Ergonomic seating should, therefore, provide the critical support needed to reduce the strain of maintaining the upright posture. But keep in mind, workers don't perform their tasks statically. They must be able to move freely about their work area. A fully adjustable chair allows the user to change seated positions and, hence, prevent blood restriction to the large muscle groups. This is especially important since restricted blood flow contributes to muscle fatigue.

Muscle fatigue isn't the only factor affecting worker productivity. Besides the intricate complex of muscles, nerves and ligaments, the back has a spine made up of a series of bones called vertebrae. Separating the vertebrae and providing a cushion are fluid-filled spinal discs. For the body to twist and move, the pliant support the spine provides is necessary.

The lower part of the back, or lumbar region, has a natural curvature. Improper seating compromises the natural curvature and eventually places uneven pressure upon the discs. Eventually, this pressure results in lower back pain -- and in extreme cases, actual disc injury -- and unhappy, unproductive workers. Therefore, in addition to providing a stable support system for the body, ergonomic seating must also provide adequate lumbar support.

With the science now behind us, let's outline what constitutes a good ergonomic chair. Several years ago, a committee of the Human Factors Society (HFS), now the Human Factors and Ergonomics Society (HFES), working in conjunction with the American National Standards Institute (ANSI), undertook the task of drafting a standard for human interaction with VDT workstations, specifically, applications performed in a seated position. This task resulted in the American National Standard for Human Factors Engineering of Visual Display Terminal Workstations (ANSI/HFS 100-1988), a technical standard that specifies conditions for acceptable implementation of human factors engineering principles.

There are literally thousands of chairs from which a telemarketing manager may choose. All ergonomically correct chairs should meet the stringent requirements of ANSI/HFS 100-1988. More and more insurance providers are recommending to their business clients seating that complies with this standard. It simply makes sense to prevent medical problems before they develop.

OVERVIEW OF ANSI/HFS 100-1988

*Seat Height -- The height of a seat shall allow the user to place feet firmly on a support surface to provide stability for the seated posture and provide lower leg support.