M. Nonnenmann, Southeastern Oklahoma State University, Durant, OK; D. Anton, University of Iowa, Iowa City, IA; F. Gerr, J. Yack, University of Iowa, Iowa City, IA.
Musculoskeletal disorders are common among agricultural workers. Within this group, dairy farmers have been identified as being at risk for knee osteoarthritis. Physical risk factors that may contribute to knee osteoarthritis include awkward postures of the knee. The purpose of this study was to quantify knee flexion exposure among dairy farmers (1) while milking and (2) while feeding in two common types of milking facilities: stanchion and parlor. Twenty-three dairy farmers performed milking and feeding tasks, 11 worked in a stanchion milking facility, and 12 worked in a parlor milking facility. An electrogoniometer was used to measure knee flexion during 30 min of the milking and feeding tasks. A split-plot repeated measures ANOVA was used to test for statistically significant differences in exposure to knee flexion while milking and feeding in both stanchion and parlor facilities. Stanchion milking results in a greater magnitude and duration of knee flexion exposure compared with feeding in a stanchion and milking and feeding in a parlor. All tasks (milking and feeding) and milking facilities (stanchion and parlor) result in exposure to knee movements and compressive forces that are greater than what is experienced while rising from a chair. The results suggest that working in stanchion milking facility results in greater exposure to physical risk factors for knee musculoskeletal symptoms such as awkward postures compared to working in a parlor milking facility. The results of this study may lead to future studies on ways to prevent exposure to knee flexion.
S. Kotowski, K. Davis, University of Cincinnati, Cincinnati, OH.
Workers in many industries, particularly parcel transportation, are faced with the challenge of lifting boxes and other objects of unknown weight. Lifting these objects often leads to unexpected loading (e.g., too much or too little), creating the potential for an injury. It is important to understand what cues workers can use to help determine the object weight before lifting, to reduce the chance of injury. The object of the study was to quantify the impact of visual and tactile cues on trunk motions when lifting varying box weights. Individuals performed asymmetric lifts using boxes weighing 4.5 kg, 9.1 kg, and 13.6 kg at 8 lifts/min. Three different lifting conditions were evaluated: (1) random known weights (RK), (2) random unknown weights (RU), and (3) unknown weights in sequence (SW). In addition, half the subjects were allowed to use a tactile cue by dragging the box off the conveyor while the other half had to lift the box over the edge. Three-dimensional trunk motion data was recorded using the lumbar motion monitor. Ratings of perceived exertion and task risk ratings were also collected. The results showed that introducing visual cues reduced trunk motions. The RU condition produced the greatest trunk motions in both sagittal and twist planes of motion when compared with the RK condition. When females couldn’t drag the boxes their lateral motion increased (~17º) while sagittal motion increased (~35º) for males for all three conditions. Twisting motions for both genders were decreased (~6-14º). While the weight lifted in each of the conditions was the same, the task risk values were greater when visual cues were not present (perceived 10% riskier). Overall, introduction of visual and tactile cues may potentially reduce the risk in low-back injuries, particularly in the male-dominated parcel transportation industry.
C. Stuart-Buttle, Stuart-Buttle Ergonomics, Philadelphia, PA; J. Colbert, The RETEC Group Inc., Fort Collins, CO.
Identifying and controlling ergonomics-related problems incurred by field staff performing a variety of tasks in different environments is difficult. The staff of an environmental engineering and service company conducted environmental sampling tests mostly at multiple outdoor sites. The safety process of the company was well established with a safety representative within each field group. To reduce the ergonomics-related injury experience and risk, a practical, multifaceted approach was devised, built on the familiar safety process, to identify the primary problems and possible interventions. In addition, unsafe behaviors, including poor body mechanics, were observed in the field, and the goal was to reduce those behaviors. An ergonomics assessment method was developed to reflect the job safety analysis process. Twenty-five safety representatives received a 6-hr training course tailored to the tasks performed and were taught how to conduct the assessments. The assessments gave insight to the common concerns being met by field staff and were used to develop a focused ergonomics and body- positioning training session for the representatives to present to their field personnel. Injury and illness results to date indicate the approach to ergonomics has been effective with an overall reduction in incidents and severity. For approximately 250 field personnel, 4 years have been tracked but cases peaked in 2005 at 7, including first aid cases through to OSHA recordable cases. In 2006 (at 9 months), there were only two first aid cases. In 2005, 11.5% of all at-risk behaviors observed were related to body positioning. The percentage decreased to 8.4% in 2006. Several interventions have also been implemented in the field, such as smaller coolers, kneeling mats, and carts. The data to date indicate a positive effect of the multifaceted approach to reduce ergonomics-related injuries and illness experience. Continued analyses will determine if there is a lasting improvement.
J. Pentikis, U.S. Army, Aberdeen Proving Ground, MD.
The use of ergonomics in the workplace to improve workstation design has increased dramatically over the past 20 years with great success, but there are still plenty of workstations that need intervention. Walk-through surveys typically reveal workstations that have been modified by employees using duct tape, bubble wrap, packing foam, and other materials that they have readily available. Although these modifications may lead to short-term comfort, they guarantee neither long-term comfort nor that these modifications are appropriate for long-term use. The sample examples presented illustrate employee modifications, limitations of these modifications, and an ergonomics basis for the changes, along with a discussion of the interventions that can be made to permanently eliminate the ergonomic hazard.
C. Lu, C. Yao, Kaohsiung Medical University, Kaohsiung City, Taiwan.
Thin-film transistor-liquid crystal display (TFT-LCD) monitors and TVs have largely replaced cathode ray tube monitors. This industry has developed rapidly and become mainstream. The manufacturing process hires many manual laborers. Particularly in the module assembly process, many operators have a high risk of musculoskeletal disorders due to long work hours and repetitive activities. The aim of the study is to evaluate the ergonomics hazards in the module assembly process. This study uses three components: (1) a questionnaire to identify musculoskeletal symptoms, (2) job analysis to evaluate the hazards, and (3) BRIEF to evaluate the potential ergonomics hazards for workers. The questionnaire results show that operators have a high frequency of musculoskeletal disorders in shoulder (59.8%), neck (49.5%), wrist (39.5%), and upper back (30.6%). Evaluations involving the BRIEF checklist have similar results to the questionnaire. Future studies should include more subjects for comparing results of the questionnaire with results of the BRIEF checklist and should evaluate the biomechanical hazards to obtain a specific result.
C. Brigham, 1Source Safety and Health Inc., Exton, PA.
Assuring the provision of high-quality education to children who have special physical and/or psychological needs can be a demanding job. Individuals providing these services have high injury and turnover rates, similar to those found in the long-term care/nursing home industry. While much attention has been paid to eliminating these conditions in long-term care facilities in recent years, little effort has been made to address this issue in our schools. There is almost no discussion in the literature of the nature and severity of exposures and potential controls.
This presentation will discuss the extent of the problem within four intermediate units that provide services to meet the needs of an organization of 80 school districts. The frequency and severity of work-related musculoskeletal disorders (WMSD) among the care/education providers will be provided, and typical exposures and controls will be reviewed.
C. Shulenberger, Clayton Group Services, Pleasanton, CA.
Experience shows that all environmental, safety, and health issues (EHS) have a combination of immediate, contributing, and root causes associated with them. Identifying and addressing the root causes, not just the immediate causes, is critical to an effective, overall EHS management system. Otherwise, the same incidents will often continue to occur at other places (e.g., workstations, sites, and facilities). In addition, if resources are spent on just addressing the immediate cause, the long-term costs will often be much greater. This presentation will provide a background in the why tree-root cause analysis process as it applies to ergonomics. A case study will demonstrate how the process identifies the immediate, contributing, and ultimately the root causes associated with an ergonomics issue. The participants will learn how to use the why tree process as a new tool or to sharpen their EHS management skills.
T. Silva, Humantech, Ann Arbor, MI.
This session highlights the use of an objective and repeatable risk assessment tool that quantifies ergonomic risk (postures, forces, frequencies, and durations) for a task or operation. Participants will learn effective approaches to (1) quantify ergonomic risk, (2) determine top ergonomic concerns, (3) prioritize ergonomic concerns, and (4) identify root causes. Building on this ergonomic risk approach, session participants will learn how to prioritize tasks or operations based on the measured ergonomic risk. Participants will learn how to identify top ergonomic concerns for the highest priority tasks and operations in a facility.
M. Wynn, Humantech, Ann Arbor, MI.
In the 1990s, a “zero injury” culture was a popular vision proclaimed by many companies, but most struggled with putting their safety vision into action. Since that time, several companies have established aggressive multiyear plans to drive their injury and illness experience down by 90% worldwide (10x improvement) — and achieved astounding results. This session will review the role that ergonomics has played in several of these companies and explore: (1) What did the company set out to accomplish? (2) Why did the company leadership embrace aggressive goals for injury/illness reduction? and (3) How did ergonomics fit into the safety improvement initiative?