Lawrence J.H. Schulze

A global survey of occupational health competencies and curriculum.

Abstract The World Health Organization has identified a world-wide shortage of occupational health professionals, but evidence suggests that the work and education of these professionals vary across countries. This survey examined the professionaldeveloprnent of occupational physicians, occupational nurses, industriaL hygienists, and ergonomists in terms of practice competencies and academic curriculum. Of 89 countries that received the survey, 48 (54%) responded. Important differences in competencies and curricula were identified for all groups. More competencies were identified more frequently in deyeloped countries. Academic programs existed more often in developed countries, but curriculum contentsvaried. The study provides a concrete reference point for discussion and developtnentof competencies and curriculum.

Torque Production Using Handwheels of Different Size During a Simulated Valve Operation Task

Opening and closing valves in industrial facilities often requires operators to use bars and wrenches as levers (cheaters) in order to overcome initial actuation forces. In order to determine more appropriate operational specifications, the maximum torque production capability was measured when 12 male participants used 4 different valve handwheels at 3 different heights and 2 different angles (in relationship to the coronal plane). The results indicate that the participants produced significantly greater torque when the largest of the 4 wheels (40.6 cm diameter) was used than when the medium (22.9 cm), small (20.3 cm), and handled (17.8 cm) handwheels were used. Although the main effect of heights was found to be statistically significant, post-hoc analyses between the heights found them to be, essentially, equal. In addition, the vertical and horizontal wheel orientations were not found to be different. The results are applicable to all industries where handwheels are used and applicable to valve manufacturers for designing operational torque specifications below the values found in this study.

Effects of pneumatic screwdrivers and workstations on inexperienced and experienced operator performance

Abstract This study investigated the effects of pneumatic screwdriver characteristics and workpiece orientation on operator productivity. Operators used four pneumatic screwdrivers (two pistol and two straight grip) representing two different clutch types (positive and automatic air shut-off). The two grip types represented both fast (1700 RPM) and slow (1000 RPM) motor speeds. The pneumatic screwdrivers were used at each of three different workstations representing different workpiece orientations (horizontal workpiece at a fixed height, horizontal workpiece with an adjustable height, and angled workpiece with adjustable height). In the first phase of the study, 18 university students (inexperienced operators) participated in a simulated furniture assembly operation. In the second phase, 16 experienced employees of a furniture manufacturing facility participated in an actual furniture assembly operation. The results of the study indicate that operators took longer to complete the required tasks and made more errors when the straight grip screwdrivers were used than when the pistol grip screwdrivers were used. These differences were more pronounced at the end of the task than at the beginning of the task. No strong performance differences were found among the three different workstations used.

Funding of pilot projects in Latin America: a tool for capacity building in occupational health research.

Abstract There is a global need for trained researchers who can address the increasing burden of illness and injury and prepare future generations of researchers. Developing countries have a special need for practical, action-oriented interventions to address workplace problems, based on identification of needs and priorities, development of locally available solutions, and consideration of the sociopolitical context of work and how best to translate research findings into policies. Effective translation and application of research products from industrialized nations to developing countries is essential, but differences in the contexts and local realities of other nations limit extrapolating such research. Funding pilot research projects in developing countries is an effective, practical, and useful tool for training new investigators in research techniques and developing collaborative relationships among countries.

Effect of pneumatic screwdrivers and workstations on operator body posture

Abstract Four pneumatic screwdrivers, representing two different motor speeds and grip types, were used by both inexperienced (college student) and experienced male and female operators in a simulated and actual furniture assembly operation, respectively. All screwdrivers were used to set screws in furniture desk tops configured in three different orientations. The workstation/workpiece orientations were chosen to assess both ideal and non-ideal upperarm-forearm, wrist, shoulder and body postures assumed by operators during the assembly task. The results of this study indicate that less deviation of the upperarm-forearm and wrist was assumed by male operators. The female operators, necessarily disadvantaged by strength and stature, assumed postures representing greater body part abduction and deviation from neutral points. No differences were found between inexperienced and experienced operators.

Torque Production Using Hand Cranks in a Simulated Gear-Operated Valve Opening Task

Hand cranks are used in a variety of industries to actuate valves and in other gear-operated applications. In order to evaluate these types of operations and their compatibility with operator strength capabilities, a rotational dynamometer was used to measure torque production capability of operators using a hand crank at different heights and angles (with respect to the coronal plane). The tests were conducted for both clockwise and counterclockwise rotations using the dominant arm of each test participant. A total of 18 tests were completed by each of five male right-handed test participants. A 0° declination angle, counterclockwise operation, and both 40.65 cm and 60.96 cm heights were found to be associated with the greatest torque production capabilities.

An exploratory study of spinal creep measurement in a simulated aircraft environment

Abstract The study of the spinal column in a vibration environment is of interest, since it can potentially affect comfort and performance across the broad spectrum of Air Force activities. Twelve Air Force male volunteers were asked to sit in each of three different aircrew seats (secured to a vibration platform) to experience a vibration environment similar to a C-130 low-level flight. Both pre- and post-vibration spinal column measurements were made using a noninvasive technique. The results of spinal column measurements revealed statistically significant differences between the three aircrew seat types used in the study. The results also lend credibility to the spinal contour measurement device as a useful tool for the measurement of the human spinal column.

Effectiveness of arm supports during typing for adults with neurological disorders.

Four computer-typing accommodations were evaluated to determine if arm supports would enhance typing performance and/or comfort of adults with neurological disorders. Each of 12 adults (6 females and 6 males) participated in 7-min typing tasks under the following conditions: 1) without arm support, 2) Ergo Rest® arm support, 3) custom arm support in fixed mode, and 4) custom arm support with movable mode. The objective dependent variables were speed, errors, and type of errors. The subjective dependent measures were reported body part discomfort, and arm support ratings. The data were found to be nonparametric in nature. Therefore, nonparametric techniques were employed to analyze the data. Only one of the objective dependent measures were statistically significant; Type of error (additional key). This result may be attributed to the wide range of disability manifestations among participants. Subjective dependent measures were found to be statistically significant, leading to the conclusion that typing with an arm support was more comfortable and easier than without an arm support.

Maximum acceptable weight of asymmetrical lifting and lowering of postal sacks

The asymmetrical lifting of postal sacks without handles was simulated. Type-2 and Type-3 postal sacks (those typically used by the U.S. Postal Service) were loaded and unloaded from and to different cart and conveyor levels. An adjustable table was used to simulate the different conveyor levels. There were six combinations of lift for each of twenty participants (ten male and ten female). A modified version of the psychophysical methodology was used to determine the maximum acceptable weight of lift. A significant difference was found between the weights lifted across cart heights. Specifically, the mean load lifted over the 96.5 cm (38.0 in) cart height was 15.337 kg (33.74 lb) and was significantly greater than the average load lifted across the 20.40 cm (8.0 in) and the 104.20 cm (41.0 in cart heights. However, this difference is not practically significant different (mean difference = 1.44 kg). There was no significant difference (p > 0.05). This lifted across table heights. A significant interaction occurred between cart height and conveyor height (p < 0.05). This interaction indicated that as the vertical distance between the cart height and the conveyor height increased, the acceptable load handling capabilities of the participants decreased. The mean MAWL for Type-2 postal sacks (14.5 kg, 31.91 lb) was similar to the mean weight lifted at the postal distribution center (16.4 kg, 36.0 lg). The mean MAWL for Type-3 sacks (14.5 kg, 31.9 lbs) was less than half of the mean weight lifted at the postal distribution center (24.6 kg, 54.1 lb). The results of this study have direct implication regarding the design of postal operations, the types of lifting and lowering tasks that should and should not be performed, as well as more practical weight limitations than are previously employed in these types of operations.

Effectiveness of workplace accommodations for a corporate telephone operator with a full left-arm prosthesis: A case study.

A corporate telephone operator and voice mail programmer was involved in a serious automobile accident resulting in left-arm amputation and through rehabilitation received a full left-arm prosthesis. Upon returning to work in her previous job capacity, some work activities and work area configurations were identified as problematic during task performance. Work methods and work area configuration were evaluated regarding their appropriateness for supporting return to work and long-term accommodation. Job activity analysis determined all reaches, clearances, and forces and their compliance with recommended criteria. A body part comfort/discomfort survey (BPCDS) was administered pre- and post-accommodation to elicit information regarding workplace problem areas and provide a measure to assess accommodation effectiveness. Workstation, support equipment, work area, seating, task assignments, and work methods were modified to more appropriately support operator task performance. Comparison of pre- and post-accommodation BPCDS indicates a significant reduction in operator discomfort with residual discomfort associated with the orthopedic prosthesis. This case study illustrates the use of the principles and techniques of industrial ergonomics to develop workplace accommodations. The area of ergonomics, medical ergonomics,is an example of the development of reasonable accommodations for physically challenged workers in the spirit of compliance with the Americans with Disabilities Act (ADA).