Here are some tips from OSHA on how to reduce work-related musculoskeletal disorders:

• Look at injury and illness records to find jobs where problems have occurred.
• Talk with workers to identify specific tasks that contribute to pain and lost workdays.
• Ask workers what changes they think will make a difference.
• Encourage workers to report symptoms and establish a medical management system to detect problems early.
• Find ways to reduce repeated motions, forceful hand exertions, prolonged bending or working above shoulder height.
• Reduce or eliminate vibration and sharp edges or handles that dig into the skin.
• Rely on equipment - not backs - for heavy or repetitive lifting.
• Simple solutions often work best. Workplace changes to reduce pain and cut the risk of disability need not cost a fortune. For example, you can offer workers involved in intensive keyboarding more frequent short breaks to rest muscles, or vary tasks of assembly line workers to avoid repeated stress for the same muscles.

Invisible threats?

Consider these hidden risk factors There is increasing evidence that psychosocial factors related to the job and work environment play a role in developing work-related musculoskeletal disorders of the upper extremity and back, according to NIOSH researchers. A NIOSH review of studies suggest that these factors are associated with various ergo-related disorders:

• Perceptions of intensified workload (time pressure, work volume and work pressure)
• Monotonous work (being bored most of the time)
• Limited job control (little autonomy)
• Low job clarity (uncertainty about job expectations or job future)
• Low social support (relations with supervisors and coworkers)

Because some of these factors are seemingly unrelated to physical demands, and anumber of studies have found associations even after adjusting for physical demands, the effects of these factors on MSDs may be, in part or entirely, independent of physical factors, according to NIOSH researchers.

It is also evident that these associations are not limited to particular types of jobs such as VDT work, or work environments such as offices, according to NIOSH. They seem to be found in a variety of work situations, according to researchers. This suggests that psychosocial factors may represent generalized risk factors for work-related MSDs.

NIOSH concludes that until most workplace and individual variables can be measured with more comparable techniques, it will be hard to determine precisely their relative impact on MSDs.

Calculate the correct height for your seat

If you have a nice chair to use while you work but you find that it tires you to sit on it, you may not be using it to its best advantage. To minimize fatigue you should sit at the correct seat height. So how do you determine this?

The most important factor is the relation of the seat height to the work level. Work level is not necessarily just the height of the desk or other work surface; it incorporates the entire distance from the floor to where the hands are doing an assigned task. For example, the work level for a lab technician may be the level where the hands are working at the microscope, not the height of the bench the instrument is resting on.

A basic formula to determine the correct seat height is the real work level (measuring from the floor to the height of the task) minus 12 inches. The resulting measurement is the correct seat height and should be the midpoint of the seat-height adjustment range of your chair.

For example: 38 in. (work level from floor to task height) -12 in. = 26 in. (mid-point of a seat-height adjustment range of 23.5 in.-28.5 in.)

This formula works for about 90 percent of workers. Most chair companies offer chairs with a seat-height adjustment range of five to six inches, though some have chairs with ranges of seven or even 10 inches.

For the 10 percent of workers whose body type makes a different seat height necessary, choose a chair company that constructs modular chairs. The seat height can be changed on the job site by simply adding or removing adapter tubes between the pneumatic cylinder and the base. Other options such as an adjustable foot ring, tilting seat and/or backrest assemblies, or a shallow ergonomic seat can be added to make a chair fit properly.

Finally, move around periodically. Ergonomists tell us that changing positions, even walking around your chair or work area, can ease muscle tension and minimize fatigue.

By Edward A. Metzger, vice president of sales & marketing, BioFit Engineered Products, Waterville, OH.; (419) 823-1089; fax: (419) 823-1342.