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Pacific Coast Nurseryman and Garden Supply Dealer

Worker is shown stooping to place cans in the field.

The field tests mark the final phase of a three-year project being conducted by a multi-disciplinary team led by Dr. John Miles, professor of biological and agricultural engineering at UC Davis, with a $621,000 grant from the National Institute for Occupational Safety and Health (NIOSH).

The UC team is focusing on musculoskeletal injuries like back strain because these disorders are, far and away, the most frequent and costly in agriculture work today. Nearly half the nursery injuries reported to California's workers' compensation system are sprains and strains, with back injuries being the worst offenders.

A typical "handle" developed for moving cans without requiring fingers pinch grip or stooped posture to pick up and replace cans on the ground.

Employers typically seek to prevent musculoskeletal injuries through training programs, teaching workers how to lift properly, for example. However, training alone is not regarded as a very effective way to reduce injuries on the job. The UC team is exploring the use of ergonomic methods for preventing injuries, reducing lost work time, and reducing workers' pain and discomfort from musculoskeletal disorders. Ergonomic methods seek to fit tools, procedures, workflow, and other aspects of a job to the worker instead of fitting the worker to the job.

Dr. Miles is collaborating with colleagues at UC's Center for Occupational and Environmental Health (COEH) in Northern California and specialists from UC Cooperative Extension and the UC South Coast Research and Extension Center in Orange County (Southern California) to reduce the hazards and develop the tools that nurseries need to prevent musculoskeletal injuries, while minimizing costs and improving efficiency on the job.

With participation from manager and employees at the three production nurseries, the researchers have identified the tasks that pose the highest risk for musculoskeletal injuries--cutting plants for propagation, carrying plants in cans, pruning, and spacing--and have developed new tools and approaches to help workers perform these tasks with improved posture, better hand grips, less lifting and twisting, and less effort.

Field Tests
For the next six months, nursery employees will use a variety of lightweight handling devices for cans and will test new, lower stress approaches to two critical tasks: off-loading containers from the canning machine and moving them to a trailer; and spacing cans in the field so that plants have adequate room to grow. Here is how each of these operations will change:

Off-loading
Standard practice: Workers stand on ground, lift three of four one-gallon cans (or one five-gallon can) in each hand off the conveyor belt from the canning machine, and twist around to place the cans on the trailer. The risk factors in this activity include highly repetitive gripping, high pinch forces as workers grasp the containers with their fingers, and high stress to the body trunk and shoulders from the lifting and twisting movement needed to move the cans to the trailer.

New Practice: Workers will stand on a catwalk slightly lower than and between the conveyor belt and the trailer. The catwalk will be at the same level as the belt and the trailer bed. The workers will use special, long-handled tools that Miles and his engineering students have designed to grip the cans as they arrive on the conveyor belt. Then, with a step-turn motion - no pinch grip or reaching - they will deposit the containers onto the trailer bed. The pinch grip is eliminated and both upper arm motion and trunk twisting are reduced.

This overview of a container-growing nursery shows the multiplicity of ornamental plants grown in plastic pots or "cans."

A canning line improvement, with worker on trailer loading cans by hand from conveyor to trailer. Note the bed of trailer is the same height as the conveyor belt, which reduces the risk of ergonomic injury.

Spacing
Standard Practice: Workers stoop to grip and lift three cans in each hand at a time, carry them to a new location, and set them down - a repetitive task that can cause pain to the fingers, hands, wrists, upper extremities, and lower back.

New Practice: Using long-handled tools that pick up every other pot, automatically fitting new spacing, workers will move the cans without stooping or using a pinch grip, thus eliminating the two highest risks leading to musculoskeletal injury. Ibis new approach is expected to improve productivity as well, because the handling tools will enable workers to move six to eight one-gallon cans at a time instead of six (or two five-gallon cans at a time).

"This kind of project doesn't get done by one or two people," said project manager and UC agricultural extension specialist, Dr. James Meyers. "Our team includes engineers, ergonomicists, public health specialists, occupational health nursing specialists, industry specialists, and the people in the participating nurseries. We needed to have a true university-industry partnership. So our first of many challenges back in the spring of 1995 was to convince the nurseries that a team of UC 'research types' would do something practical!"

Challenge No. 1:
Convincing the Nurseries to Participate
Team member John Kabashima, environmental horticulture advisor with UCCE, Orange County, provided the credibility the researchers needed. "John comes from a nursery background and as a cooperative extension advisor specializing in nursery production, he has an intimate understanding of the business, and the owners trust him," Meyers said. "They knew he would take their perspective seriously, and he got us to understand the industry's profile and problems so that our work and suggestions would be relevant."

Another boost came from the team's project coordinator, Diana Tejeda of the UC South Coast Research & Extension Center. Fresh out of graduate school with a degree in engineering, Tejeda became the day-to-day liaison to the nurseries.

"Since most of the workers are Spanish speaking, the fact that Diana speaks fluent Spanish, is around all the time, and has developed great rapport with everyone has built up enormous reservoirs of trust," Dr. Meyers said. "She has been able to motivate people to try new approaches and stick with them, even if the tasks seemed uncomfortable and unfamiliar at first. For example, it takes three days to get used to picking up pots by handles. The first day is slow and awkward. But by the third day, the workers won't give the handles back."

To understand the elaborate, year-round production process that the nurseries used, the team started out by learning systematically about the flow of work. Kabashima and Tejeda observed and described 50 different tasks, then illustrated the entire work process on paper so that ergonomicist Ira Janowitz of COEH's Ergonomics Program in Richmond, California, could begin evaluating what elements of the work experience might cause people to become injured or develop cumulative trauma disorders - ergonomic risk factors such as awkward postures, highly repetitive motion, high forces which can cause strain, and pressure from hard surfaces on soft tissues.

Challenge No. 2:
Knowing What Needed to Be "Fixed"
The team's next challenge was to rate all 50 tasks for the presence of risk factors associated with cumulative trauma disorders (CTDS) such as tendonitis or back strains. To do this, Janowitz and Tejeda observed nursery employees in the field and rated the riskiness of their tasks using checklists Janowitz had modified to make them appropriate for nursery work, which is more arduous than work in other industries.

Escala de Caras de Dolor

Cada cara representa un estado de ánimo diferente. La cara feliz representa a una persona contenta porque no tiene dolor, y la cara triste represents una persona que siente un poco de dolor o mucho dolor. La Cara 0 se siente muy feliz porque no tiene dolor. La Cara I tiene poco dolor. La Cara 2 tiene un poquito más de dolor. La Cara 3 tiene más dolor todavía. La Cara 4 tiene mucho dolor. La Cara 5 tiene tanto tanto dolor que le hace llorar. ¿Cuál de estas caras mejor representa el dolor que siente usted?

Here is the scale interviewers used to assess symptom severity, specifically pain severity, among Hispanic nursery workers participating in the research project. The scale was endorsed by the workers as they believe it can easily be used by fellow workers in nursery settings. The need to be literate in Spanish (or English) is minimized if the scale is administered by an interviewer, rather than as a pencil-and-paper questionnaire. The scale was adapted from one used to assess pain in children and customized for Spanish-speaking adults for the research study. Courtesy Dr. Julia Faucett, UC San Francisco.

Challenge No. 3:
Showing that the "Fix" Really Makes a Difference
It was one thing to change how the nursery workers would carry out their jobs and another to learn whether these changes would actually improve their health. The responsibility for documenting musculoskeletal problems before and after introducing changes fell to Dr. Julie Faucett, director of Occupational Health Nursing, at UC San Francisco. Anticipating that the rate of injuries and CTDs would decrease as ergonomic risk factors were reduced, Faucett and Tejeda studied the injury and illness records of the three nurseries to develop a baseline for comparing injuries before and after changes were made.

As it turned out, it appeared that the numbers would be too small and the project timeline too short to draw a conclusion that would be statistically significant from a formal scientific point of view. So, knowing that people often have unreported pain and symptoms of musculoskeletal disorders, Faucett developed a second approach. Working directly with the nursery employees to identify and eliminate any cultural or language barriers, she designed an employee health survey that can be delivered in Spanish or English and focuses on musculoskeletal symptoms and work tasks. This pioneering survey represented a risk for the participating nurseries. Employers are often not keen on pain and symptoms survey, out of concern that such survey might increase the number of reported injuries. However, Tejeda has now conducted the survey at all three nurseries, and according to cooperators, no increase in reported injuries has occurred.

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Accessing Research Help
Most states have a Land Grant College, funded by the USDA to perform agricultural research and extension work. The University of California's Land Grant work is organized under the UC Division of Agriculture and Natural Resources. Researchers and Extension Specialists are located on the Berkeley, Davis, and Riverside campuses and Farm Advisors are located in County Extension Offices. This project is funded by the National Institute for Occupational Safety and Health. To see if there are funded research opportunities for projects of special interest to you, take the following steps: 1. Be specific in identifying your problem or need; 2. Contact your local Farm Advisor to identify UC researchers with pertinent interest and expertise; 3. They can review related funding opportunities, but so can you through a search on the World Wide Web, for example. Most funding agencies and foundations have web sites; 4. Work together on a funding proposal, and; 5. Remember, interest by researchers and funding agencies in joint public-private ventures is increasing.
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Challenge No. 4:
Agreeing on Priorities
By the summer of 1995, Janowitz had collected preliminary data on the highest ergonomic risk factors, and Faucett's review of injury records had revealed which tasks had most often been associated with injury. Then, the team interviewed managers to get their list of the tasks they thought were the most likely to cause back injuries, strains, and sprains. Not surprisingly, the researchers' lists and the managers' lists were very similar.

"We sat down with the managers to decide which four tasks to tackle, and selected plant cutting, container handling, pruning in the field, and spacing," said Dr. Meyers.

Challenge No. 5:
Measuring Motion Objectively
To gather real-time data in the field, Janowitz next introduced two new measuring instruments, the Lumbar Motion Monitor (an instrument worn on the back that helps determine the likelihood of back injury by measuring the amount and the speed of bending and twisting involved in doing a task) and the Greenleaf Wrist Movement Analysis System (a pair of fingerless gloves with sewn-in sensors that measure how much people bend their wrists while performing a task). Excessive bending, especially when done rapidly and repeatedly, is associated with CTDS, The Greenleaf system and the Lumbar Motion Monitor had not been used in agricultural settings, although their value had been well established in other industries.

Here the team faced its first test of participation. These instruments are not uncomfortable to wear, and do not limit movement. But, "the workers were reluctant to wear these instruments, because they didn't want to attract attention or be distracted from their work, Meyers explained, "but they did it for Diana."

Challenge No. 6:
Making Useful, Practical Changes
With the means for evaluating health outcomes in place and more ergonomic measurements underway, the next big research challenge was to come up with practical tools that would reduce ergonomic hazards - without breaking the bank. Enter the engineers.

Dr. Miles and his students designed different kinds of lightweight handles, raised working platforms to eliminate twisting and lifting, tilting trailers, and powered clippers, among other prototypes. Tejeda and Kabashima had the nursery employees test each prototype, then sent their comments back to UC Davis, where the engineers made improvements. Meanwhile, according to Meyers, the managers were continually cautioning, "No gadgets. Keep it simple."

"As a result of this process of trial, error, and feedback, the tools became more ergonomically sophisticated, but stayed simple," Meyers added. "The engineers were a rich source of innovation, and they gave us a few laughs, too. The last prototype they sent down before we had to stop designing and start testing was a kind of rolling platform for the trailer so that the nursery workers wouldn't have to reach and stretch to retrieve the containers. The Davis crew named it the 'Lazy Diana' (as in Lazy Susan) after our hard-working project coordinator. The name was an instant hit."

Still, not all the problems have been solved. "We're having trouble finding a practical and cost-effective powered clipper for the task of making cuttings for plant propagation," Meyers advised. "Design work will continue by the engineers because this is a task that does cause CTDS, but it is disappointing that we haven't been able to identify a practical commercially-produced clipper for the job."

Challenge No. 7
Putting It All Together
The six-month trial that began January 1 is testing the new designs for handling cans and spacing plants in the field and evaluating their effect on ergonomic risk factors, musculoskeletal pain and symptoms, other nursery activities, costs, and productivity. Managers and workers will participate in this evaluation. Both groups must accept the changes being proposed if they are to adopt them successfully. The Lumbar Motion Monitor, Greenleaf Wrist Movement Analysis System, and other approaches used by Janowitz and Tejeda before the interventions, will be repeated after the changes are in place to evaluate the amount of twisting and bending of the back and wrist, as well as the worker's energy expenditure and the stress on the body. "We want to be sure that we don't substitute one problem for another (e.g., in other parts of the body)," Janowitz notes.

While the team won't have final results until October, preliminary measures of the use of handles for spacing plants in the field indicate that the new tools improve body posture significantly: they reduce twisting by 30%, reduce pressure on the spine from lifting by 60%, and reduce forward bending by 15%. While these measurements still need to be confirmed, taken together, these improvements suggest significantly reduced probability of long-term back injury for workers on this job.

"This research is just a first step in tackling ergonomic problems in agriculture, but it is a critical step," said James Meyers. "Commercial nurseries are one of the fastest growing segments of California agriculture, employing some 31,000 workers. The nurseries cooperating with us in this research specialize in container-grown ornamentals, primarily for delivery to retail nurseries. All are large operations by industry standards, accounting for a total of nearly 1,300 employees. They are playing a pioneering and an invaluable role in demonstrating the efficacy of ergonomic methods for preventing musculoskeletal disorders."

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LEFT PHOTO: Worker shown using a "handle" to unload 5-gal. cans from a trailer in the field. Note the height of the trailer.
RIGHT PHOTO: Worker carrying multiple 1-gal. cans in handles. It takes three days to get used to handling the tool.


UPPER LEFT: Early prototype powered clipper for making plant cuttings. UPPER RIGHT: Worker using prototype powered clipper for making plant cuttings.
LOWER LEFT: Worker being fitted with Lumbar Motion Monitor which provides detailed ergonomic data.
LOWER RIGHT: Worker making plant cuttings with GreenLeaf Wrist Movement Analysis System which provides extensive ergonomic data on tasks related to work. The equipment will enable researchers to evaluate the amount of twisting and bending of the back and wrist, as well as the worker's energy expenditure and stress on the body.

ON LEFT: Worker carrying one 5-gal. can in each hand with handles.
AT RIGHT: Workers placing cans on ground in field with handles. Full body stooped posture is eliminated. UC researchers are working with 3 major California nurseries on this project.