Research Interests:
Research Interests:
Sumario: The design of hand tools to minimize anatomical deviations from neutral positions is intuitively attractive. However, in the case of bent pliers, this accomodation of the human subject has been shown to result in a lower... more
Sumario: The design of hand tools to minimize anatomical deviations from neutral positions is intuitively attractive. However, in the case of bent pliers, this accomodation of the human subject has been shown to result in a lower performance on a simulated wire-twisting task. The level of the decrement depended on the workplace characteristic of vertical workpiece location, confirming the concept that the design of the hand tool is not independent of the design of the workplace. Additonally, training likely will be required for both managers and operators
Research Interests:
DESCRIPTION Ph.D. Dissertation, Texas Tech University
ABSTRACT
Research Interests:
Research Interests:
... Personnel training for safer material handling. Ergonomics, 35(9), 1119-1 134. Liles, DH, Deivanayagam, S., Ayoub, MM, and Mahajan, P. (1984). A Job Severity Index for the Evaluation and Control of Lifting Injury. Human Factors,... more
... Personnel training for safer material handling. Ergonomics, 35(9), 1119-1 134. Liles, DH, Deivanayagam, S., Ayoub, MM, and Mahajan, P. (1984). A Job Severity Index for the Evaluation and Control of Lifting Injury. Human Factors, 26(6), 683-693. ...
Research Interests:
Research Interests:
ABSTRACT Occupational disease and losses from badly-designed handles on hand tools are major concerns to the manufacturing industry. Of particular concern are hand tools, such as pliers, which require Unar deviation of the wrist. Direct... more
ABSTRACT Occupational disease and losses from badly-designed handles on hand tools are major concerns to the manufacturing industry. Of particular concern are hand tools, such as pliers, which require Unar deviation of the wrist. Direct evidence for such disease and losses has long been provided by a Western Electric study which compared the cumulative trauma disorder occurrences among two groups of trainees using bent and straight-handled pliers. A review of this finding indicated that such losses were unusually high and numerically identical to subjective physical responses from a laboratory-based study concerned with the design of handles for nut drivers.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests: Psychology, Ergonomics, Workplace, Humans, United States, and 16 moreFemale, Male, Restaurants, Questionnaires, Bureau of Labor Statistics, Research Needs, Adult, Cross Section, Human Engineering, Assessment Tool, Cross sectional Study, Lifting, Wounds and Injuries, Cross Sectional Studies, Task Performance and Analysis, and Working Hours
Research Interests:
Research Interests:
Workers' compensation claims associated with manual materials handling (MMH) represent the single largest source of claims and costs. Surprisingly, there have been few analyses of such losses associated with MMH. An examination of... more
Workers' compensation claims associated with manual materials handling (MMH) represent the single largest source of claims and costs. Surprisingly, there have been few analyses of such losses associated with MMH. An examination of the nature of the injuries associated with MMH as well as the body parts most frequently affected can lead to a better understanding of the losses attributed to MMH to suggest further research efforts. A large sample of MMH claims was analysed and stratified with respect to body part affected and the nature of the injury. The outcome measures examined were frequency (number of claims) and severity (cost measures) of the claims. The analyses revealed that the lower back area and upper extremities were the body parts associated with approximately 70% of the claims. Strain was the nature of injury most frequently reported (51.3%). Lower back area strains were the most frequently reported nature of injury and body part combination. Additionally, an analysis of median claims costs revealed the occurrence of a small number of very expensive traumatic injuries.
Research Interests:
Research Interests:
ABSTRACT Don't assume that a tool developed for one task will be applicable to all tasks requiring the same tool.
Research Interests:
Several tools are sold and recommended for closing and sealing flexible intermediate bulk containers (bulk bags) which are used to transport product that has been mined and processed. However, there is limited information on the risks,... more
Several tools are sold and recommended for closing and sealing flexible intermediate bulk containers (bulk bags) which are used to transport product that has been mined and processed. However, there is limited information on the risks, physical demands, or the benefits of using one tool over another. The purpose of this study was to evaluate the physical demands involved with two closing methods and several sealing tools in order to provide recommendations for selecting tools to reduce exposure to risk factors for work-related musculoskeletal disorders. In this study, twelve participants completed bag closing and sealing tasks using two different closing methods and eight sealing tools on two types of bulk bags. Physical demands and performance were evaluated using muscle activity, perceived exertion, subjective ratings of use, and time. Results indicate that using the " flowering " method to close bags required on average 32% less muscle activity, 30% less perceived exertion, 42% less time, and was preferred by participants compared to using the " snaking " method. For sealing, there was no single method significantly better across all measures; however, using a pneumatic cable tie gun consistently had the lowest muscle activity and perceived exertion ratings. The pneumatic cable tie gun did require approximately 33% more time to seal the bag compared to methods without a tool, but the amount of time to seal the bag was comparable to using other tools. Further, sealing a spout bulk bag required on average 13% less muscle activity, 18% less perceived exertion, 35% less time, and was preferred by participants compared to sealing a duffle bulk bag. The current results suggest that closing the spout bag using the flowering method and sealing the bag using the pneumatic cable tie gun that is installed with a tool balancer is ergonomically advantageous. Our findings can help organizations select methods and tools that pose the lowest physical demands when closing and sealing bulk bags.
Research Interests: Ergonomics and Mining
Research Interests:
Research Interests:
The ability to accurately estimate grip force requirements may be important in exposure assessment, determining fitness for duty, or setting rehabilitation goals. This study investigates the effects of learning and experience, measurement... more
The ability to accurately estimate grip force requirements may be important in exposure assessment, determining fitness for duty, or setting rehabilitation goals. This study investigates the effects of learning and experience, measurement system, and the nature of the task on grip force estimate accuracy. The grip forces applied during "pure" power grip tasks and simulated meat cutting tasks conducted in the laboratory, and during meat cutting operations at meat packing plants were measured with an instrumented tool handle. Estimates were recorded using the tool handle and a modified hand dynamometer. The results indicate that estimate accuracy varied greatly from individual to individual. No significant effect of learning on estimate accuracy was observed. The result of the meat cutting simulation and field study suggest that the force distribution at the hand-tool interface can markedly affect estimates. Great care must be taken in the collection of grip force estimates, as well as in the interpretation of the data. Improved understanding of the factors affecting estimates of grip force requirements should aid in the interpretation of functional capacity evaluations, and in the establishment of goals for rehabilitation.
Research Interests:
ABSTRACT We evaluated maximum acceptable forces and physiological responses simultaneously in 12 men and 15 women workers while dynamic pushing. First, a psychophysical approach was utilized to identify participants' maximum... more
ABSTRACT We evaluated maximum acceptable forces and physiological responses simultaneously in 12 men and 15 women workers while dynamic pushing. First, a psychophysical approach was utilized to identify participants' maximum acceptable forces to be pushed on 3 surfaces: treadmill belt; plywood floor; and teflon floor. Second, while pushing for two hours at their psychophysically chosen force, cardiopulmonary and calf muscle oxygen saturation were collected. In both men and women, higher whole-body oxygen uptake per force coupled with increased muscle oxygen saturation per force on teflon floor were observed, suggesting that pushing on the slippery teflon floor is metabolically more challenging for all workers than on other surfaces. Interestingly, the muscle oxygen saturation-force ratio in women was higher compared with men on treadmill (by 29%), on teflon (by 30%), and on plywood floor (by 72%). These findings suggest the strong influence of force exertion on muscle oxygen saturation in women versus men.
Research Interests:
We evaluated maximum acceptable forces and physiological responses simultaneously in 12 men and 15 women workers while dynamic pushing. First, a psychophysical approach was utilized to identify participants' maximum acceptable forces... more
We evaluated maximum acceptable forces and physiological responses simultaneously in 12 men and 15 women workers while dynamic pushing. First, a psychophysical approach was utilized to identify participants' maximum acceptable forces to be pushed on 3 surfaces: treadmill belt; plywood floor; and teflon floor. Second, while pushing for two hours at their psychophysically chosen force, cardiopulmonary and calf muscle oxygen saturation were collected. In both men and women, higher whole-body oxygen uptake per force coupled with increased muscle oxygen saturation per force on teflon floor were observed, suggesting that pushing on the slippery teflon floor is metabolically more challenging for all workers than on other surfaces. Interestingly, the muscle oxygen saturation-force ratio in women was higher compared with men on treadmill (by 29%), on teflon (by 30%), and on plywood floor (by 72%). These findings suggest the strong influence of force exertion on muscle oxygen saturation i...
Research Interests:
This study represents a continuation of a series of psychophysical studies on repetitive motions of the wrist and hand conducted at the Liberty Mutual Research Center for Safety and Health. The purpose of the study was to quantify maximum... more
This study represents a continuation of a series of psychophysical studies on repetitive motions of the wrist and hand conducted at the Liberty Mutual Research Center for Safety and Health. The purpose of the study was to quantify maximum acceptable torques of six motions performed on separate days but within the context of the same experiment. The six motions were screw-driving clockwise with a 31-mm handle, a 40-mm handle, and a 39-mm yoke handle; screw-driving counterclockwise with a 31-mm handle; ulnar deviation with a power grip (similar to knife cutting), and a handgrip task (similar to a pliers task). A psychophysical methodology was used in which the subject adjusted the resistance on the handle, and the experimenter manipulated or controlled all other variables. Ten subjects performed the six tasks at repetition rates of 15, 20, and 25 motions per minute. Subjects performed the tasks for 7 hours per day, 5 days per week, for 4 weeks. The subjects were instructed to work as ...
Research Interests: Humans, Movement, Female, Wrist joint, Middle Aged, and 4 moreUlna, Adult, Torque, and Task Performance and Analysis
To investigate lifting-related musculoskeletal disorders in metal processing, to analyze the risk factors, and to study the validity and feasibility of using NIOSH lifting equation in China. The questionnaires of semi-structured... more
To investigate lifting-related musculoskeletal disorders in metal processing, to analyze the risk factors, and to study the validity and feasibility of using NIOSH lifting equation in China. The questionnaires of semi-structured interview, the Ovako Working Posture Analysing System (OWAS) postural analysis and variables of the NIOSH equation were applied to the study. The study population consisted of 69 workers mainly involved in manual materials handling (MMH), categorized as Job A; and 51 machinery workers, served as controls, that were less MMH task involved, as Job B. The prevalence of low back pain (LBP), which was defined at least one episode lasting for more than 24 hours in the past 12 months, were 63.8% and 37.3% for Job A and Job B, respectively. However, the prevalence of LBP lasting for more than a week due to lifting were 26.09% and 5.88% for Job A and B, respectively. The proportion of awkward back postures were found higher in Job A than that of Job B (66% vs 63%, P ...
Research Interests:
Research Interests: Simulated Annealing, Risk assessment, Neural Network, Humans, Variable Selection, and 12 moreApplied Ergonomics, Combinatorial Problems, Medical Physiology, Feedforward Neural Network, Theoretical Models, Data classification, Human Engineering, Error Back-Propagation, Risk Assessment, Statistical Model, Occupational Diseases, and Prediction Accuracy
OCCUPATIONAL APPLICATIONS This analysis identified patterns in fatalities during maintenance and repair operations in mining. U.S. mining maintenance and repair fatal reports (2002–2011) were reviewed and used to develop a classification... more
OCCUPATIONAL APPLICATIONS This analysis identified patterns in fatalities during maintenance and repair operations in mining. U.S. mining maintenance and repair fatal reports (2002–2011) were reviewed and used to develop a classification scheme. Fatalities were classified using this scheme, and proximal causes, tasks performed, and contributing factors were identified, as well as differences in patterns between coal and metal/nonmetal mines. Based on the results, possible interventions to reduce fatality occurrences are discussed. Primary suggestions include ensuring that workers are knowledgeable about and understand the importance of following proper de-energizing and lock out/tag out procedures, particularly in coal mines where the proportion of electrical-related deaths is significantly higher than in metal/nonmetal mines, and proper blocking procedures. Effort should be made to ensure that safety equipment and personal protective equipment are available and used where needed, e...
To determine the anthropometric parameters and the isometric muscle strength in a working population sample in China, and to investigate the relationship between muscle strength and individual attributes, such as age, gender, height and... more
To determine the anthropometric parameters and the isometric muscle strength in a working population sample in China, and to investigate the relationship between muscle strength and individual attributes, such as age, gender, height and weight. The study population consisted of 146 male and 47 female people including workers, administrators and college students. Four types of muscle strength, i.e., handgrip, arm lift, shoulder lift, and torso pull, were measured. Left handgrip, right handgrip, arm lift, shoulder lift and torso pull of male workers were (42.07 +/- 7.20), (43.92 +/- 7.14), (26.79 +/- 4.64), (33.79 +/- 6.88), (88.56 +/- 17.98) kg, respectively while those of female workers were (21.29 +/- 5.09), (23.26 +/- 5.47), (13.29 +/- 3.37), (18.52 +/- 4.01), (41.06 +/- 12.04) kg, respectively. The female's strength was about 50% lower than the male's. The strength in the 40 approximately years old group was higher than that in other age groups. There were significant pos...
Research Interests:
A previous experiment by the authors investigated the effect of the design of pliers on productivity. A simulated wire-twisting task performed at five heights between 10 inches above and 10 inches below elbow height formed the basis of... more
A previous experiment by the authors investigated the effect of the design of pliers on productivity. A simulated wire-twisting task performed at five heights between 10 inches above and 10 inches below elbow height formed the basis of the comparison. Pliers designed according to the American National Standard for long nose and long reach pliers were compared to bent-handled pliers designed at the Western Electric (WE) Co. The WE pliers, designed to reduce ulnar deviation during a wire-twisting task, resulted in productivity decrements between 1.4 and 17% across the five heights studied. The current experiment was a continuation of that study, adding orientation of the workplace in the sagittal plane as an independent variable. Wrist deviation in two planes were additional dependent measures, and the experiment was performed by female subjects with a mean age of 48.1 years. The results did not indicate a significant difference between productivity levels for the two pliers designs. ...
Research Interests:
ObjectivesTo quantify the variance introduced to trapezius electromyography (EMG) through normalization by sub-maximal reference voluntary exertions (RVE), and to investigate the effect of increased normalization efforts as compared to... more
ObjectivesTo quantify the variance introduced to trapezius electromyography (EMG) through normalization by sub-maximal reference voluntary exertions (RVE), and to investigate the effect of increased normalization efforts as compared to other changes in data collection strategy on the precision of occupational EMG estimates.
Research Interests:
Research Interests: Humans, Movement, Female, Wrist joint, Middle Aged, and 4 moreUlna, Adult, Torque, and Task Performance and Analysis
ABSTRACT The purpose of this experiment was to compare the differences in maximum acceptable forces of a 7.6 m pushing task at a frequency of 1 min-1 between a high-inertia pushcart and our criterion magnetic particle brake treadmill push... more
ABSTRACT The purpose of this experiment was to compare the differences in maximum acceptable forces of a 7.6 m pushing task at a frequency of 1 min-1 between a high-inertia pushcart and our criterion magnetic particle brake treadmill push task (Snook and Ciriello, 1991). Thirty female and 22 male industrial workers performed both a pushcart and a treadmil pushing task in the context of four larger experiments. The results revealed that maximum acceptable sustained forces of pushing on the pushcart were essentially identical to our magnetic particle brake treadmill data whereas the maximal acceptable initial forces were 7% to 15% higher than the criterion for males and females respectively. These findings may indicate that adjustments to our maximum acceptable sustained force data may not be necessary, however, maximum acceptable initial forces may present conservative estimates.