Twisting, bending add to HCW ergo risk

Reduce hazards by changing environment

Heavy lifting isn't the only strain causing musculoskeletal injuries in health care workers. Hospital employees are often twisting and bending sideways with trunk flexions and rotations that contribute to their risk of injury, according to a large observational study conducted by researchers at the University of Massachusetts Lowell.

The study suggests that lift equipment only is one aspect of reducing ergonomic hazards in hospitals. "It's not going to eliminate all of the stress in the back because it's not all from lifting," says Laura Punnett, ScD, professor in the university's department of work environment.

The study, funded by the National Institute for Occupational Safety and Health (NIOSH), involved 23,071 direct observations in 94 observation periods in two hospitals and two nursing homes. The hospitals and nursing homes varied in their use of patient lift equipment.

Six trained observers looked for "ergonomic exposures to sagital trunk flexion greater than 45 degrees, axial rotation and lateral bending greater than 20 degrees, manual load handling greater than 10 pounds," as well as other characteristics of work.

There were some differences between the nursing home and hospital activities. "Nursing home employees, mostly nurses and aides, are spending a lot of time bent over taking care of residents in beds and chairs," says Punnett. Height-adjustable beds could help reduce that ergonomic hazard, she adds.

The many varied jobs in hospitals produced a wide range of risks. For example, staff nurses, along with rehabilitation therapists and nurses' aides and orderlies had the highest exposures to trunk bending, while nurses' aides and orderlies faced the greater manual load handling from their tasks in patient transfers.

Laboratory workers, diagnostic technicians, and dialysis technicians were often twisting and had the highest rank for axial rotation and lateral bending.

Some of the awkward postures related to equipment layout, and the researchers provided suggestions to the hospital after the observations to improve the work environment, Punnett says.

For example, equipment that is used most often should be positioned close to the employee, so he or she doesn't have to reach. "Heavy items should be stored as close to waist height as possible as opposed to on the floor or above chest height," Punnett advises.

A trained ergonomist can identify potential hazards and suggest workplace changes, she says.

Jobs that had ergonomic hazards included:

  • Food service employees who had repetitive upper-extremity work and prolonged standing.
  • Laundry and custodial workers who had dynamic pushing and pulling of carts and lifting of heavy bags of laundry, trash, and biohazard waste.
  • Maintenance and repair staff, with a wide variety of tasks that involved awkward postures, heavy lifting, and vibrations from powered tools.

The study also showed that direct observations can provide a unique view of job hazards. Asking workers about their daily activities simply cannot capture all the potential concerns, says Punnett.

"A lot of questions have been raised about how accurately people can report their own exposures," she says. "You can't see your own back position, you're not counting how much time you spend doing one thing vs. another."

Punnett and her colleagues developed the observational technique while observing the construction trades. It is based on an industrial engineering technique called work sampling, in which observations are used to determine how often a machine is in use.

The observational method was successful, and provides information that can be used along with workers' compensation and injury data and employee surveys to gain a better understanding of ergonomic hazards, she says. The study was part of the five-year PHASE (Promoting Healthy and Safe Employment in Healthcare) study, sponsored by NIOSH and conducted by the University of Massachusetts Lowell.1


1. Boyer J, Tessler J, Park J, et al. Development of a group-based ergonomic assessment strategy for characterizing physical workload in healthcare workers. Proceedings of the Human Factors and Ergonomics Society 50th Annual Meeting 2006; 1,107-1,111.