Success Brief:The County engaged an ergonomist who implemented a four-phased approach that was effective in decreasing work-related upper limb musculoskeletal disorders (MSDs) among bus operators by nearly 30 percent.
According to the San Mateo County Transit Districtís risk management group, surveillance data collected for work-related MSDs revealed 103 work-related MSDs over an approximately three-year period. The distribution among 320 bus operatorís showed that 66 percent of the injuries were upper limb in nature (20 percent - upper arm, 36 percent - hand/wrist, 8 percent - elbow, and 1 percent - shoulder). The mechanism of injury for this category appeared to be steering and ticketing. Another 21% of the injuries were related to different parts of the spine due both to prolonged sitting and to strapping wheelchair customers in place.
The County contracted with an ergonomist who investigated and addressed the problem utilizing a four-phased approach (assessment, analysis, implementation, and evaluation).
Phase one consisted of an assessment or evaluation of potential risk factors for work-related MSDs that involved interviews with a sample population of 8 bus operators. The interviews focused on the bus operatorsí perceived hazards while driving their routes, and included direct observation of various operator task activity and interaction (e.g., adjusting route signs, mirrors, and seats, etc.) using video and digital photography.
During the second phase of the project, the ergonomist analyzed all of the meaningful and relevant data collected from phase one, performed necessary research, and developed a task analysis report with a full risk prioritization of all reasonable recommendations (e.g., design and redesign changes for the bus workstation and other related tools to include a wheelchair strapping mechanism, administrative changes, training, etc.). Also, project timelines and logistics were considered.
The third phase involved the actual implementation of the recommended action items, such as the gradual transition to more shock absorbing and adjustable bus seats. However, because most of the root causes of the work-related MSDs appeared to be due to unsafe behaviors, ergonomic team training was scheduled immediately. This consisted of a six-hour train-the-trainer program for the Countyís four full time trainers conducted by the ergonomistís consulting team. Training materials (e.g., a trainerís binder with program administration section and a narrated slide presentation, 30-page traineeís manual, wallet-sized stretching and strengthening cards, generic and worksite-specific videos, posters, etc.) were customized to match the different task activities of the operators. Then the certified trainers conducted two-hour sessions for the entire bus operator workforce over a six-week period. All of the operators were then tested on their ergonomics knowledge, such as identifying risk factors, understanding how their body works, fitness, and movement. In addition, each operatorís adoption of the necessary skill set was evaluated using a Lift Alert 2000 Monitor that attaches to the operatorís collar to detect aberrant motion in the frontal plane while performing lifting tasks.
The fourth and final phase was an evaluation of the programís effectiveness. This program evaluation included outcome tracking of work-related MSD incidence rates at 9-, 12-, and, 18-month intervals.
The evaluation phase provided evidence that the ergonomics program was effective in decreasing work-related musculoskeletal disorders for the bus operator population by nearly 30 percent. Further reduction is likely as a result of the recent implementation of an upgraded version of the ergonomic team training (actual results are pending).
Source:Chuck Sherrod, DC, MPH, CIE, California Health Consultants, Inc. (September 2003).