@article{shivers_mirka_kaber_2002, title={Effect of grip span on lateral pinch grip strength}, volume={44}, ISSN={["1547-8181"]}, DOI={10.1518/0018720024496999}, abstractNote={ Repetitive, high-force pinch grip exertions are common in many occupational activities. The goal of the current study was to quantify the relationship between lateral pinch grip span (distance between thumb and index finger) and lateral pinch grip strength. An experiment was conducted in which 40 participants performed maximal lateral pinch grip exertions at 11 levels of grip span distances (0, 10%, ... 100% of maximum functional lateral pinch grip span distance). The results show a significant effect of lateral pinch grip span, with strength at the maximum functional lateral pinch grip span 40% higher than that found at the smallest lateral pinch grip span considered. Between these two endpoints, strength increased monotonically with increasing pinch grip span. The application of these results in pinch grip design criteria for both high-force and long-duration exertions is discussed. Potential applications of this research include the design of hand tools and controls for which significant force is applied by the user. }, number={4}, journal={HUMAN FACTORS}, author={Shivers, CL and Mirka, GA and Kaber, DB}, year={2002}, pages={569–577} }
 @article{sommerich_starr_smith_shivers_2002, title={Effects of notebook computer configuration and task on user biomechanics, productivity, and comfort}, volume={30}, ISSN={["0169-8141"]}, DOI={10.1016/S0169-8141(02)00075-6}, abstractNote={This study took a comprehensive approach to evaluating effects of using a notebook computer stand-alone or along with inexpensive peripheral input devices. The study examined effects on biomechanics, productivity, and discomfort, and considered the impact of both computer configuration and task performed. It was hypothesized that, in general, the stand-alone configuration would induce greater postural fixity and more non-neutral postures than configurations with peripheral input devices. Dependent measures included muscle activity, posture and posture variation/fixity, productivity, and subjective assessments of discomfort and preference. The data were generally consistent with the hypothesis, though some biomechanical advantages were identified for each configuration; specifics and exceptions are discussed, along with reasons for a general recommendation for the use of an external mouse, or mouse and keyboard (without number pad) when using a notebook computer for an extended period of time, as in a desktop replacement scenario. Notebook computer use is rapidly increasing, in industry and schools. Yet the notebook form factor is inconsistent with a number of current design recommendations. Little research concerning physical ergonomics of notebook computer use has been conducted, so recommendations for use are currently limited and not strongly supported by objective evidence.}, number={1}, journal={INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS}, author={Sommerich, CM and Starr, H and Smith, CA and Shivers, C}, year={2002}, month={Jul}, pages={7–31} }
 @article{mirka_smith_shivers_taylor_2002, title={Ergonomic interventions for the furniture manufacturing industry. Part I - lift assist devices}, volume={29}, ISSN={["0169-8141"]}, DOI={10.1016/S0169-8141(01)00067-1}, abstractNote={The objectives of this intervention research project were to develop and evaluate engineering controls for the reduction of low back injury risk in workers in the furniture manufacturing industry. An analysis of injury/illness records and survey data identified upholsterers and workers in the machine room as two occupations within the industry at elevated risk for low back injury. A detailed ergonomic evaluation of the activities performed by these workers was then performed and the high risk subtasks were identified. The analysis for upholsterers revealed: (1) high forces during the loading and unloading of the furniture to and from the upholstery bucks, (2) static awkward postures (extremeflexion>50°, lateralbending>20°, twisting>20°) during the upholstering of the furniture, and (3) repetitive bending and twisting throughout the operation. For machine room workers, this ergonomic evaluation revealed repetitive bending and twisting (up to 5 lifts/min and sagittal flexion>80°, lateral bending>15°, twisting>45°) when getting wooden components from or moving them to the shop carts that are used to transport these materials. Engineering interventions were then developed and evaluated in the laboratory to document the reduction of exposure to these stressors. The height-adjustable upholstery buck system eliminated the lifting and lowering requirements and affected trunk kinematics during the upholstery operation by reducing peak sagittal angles by up to 79% (average: 52%; range: 27–79%), peak sagittal accelerations by up to 42% (average: 71%; range: 0–74%) and peak lateral position by up to 31% (average: 20%; range: 12–31%), and showed no impact on time to complete the task. The machine room lift reduced peak sagittal angle by up to 90% (average: 76%; range: 64–90%), peak sagittal accelerations by up to 86% (average: 72%; range: 59–86%) and had a positive impact on the time to complete the task (average reduction: 19%). The ergonomic intervention research documented in this report shows the impact of engineering controls for the furniture manufacturing industry on the risk factors for work-related low back injuries.}, number={5}, journal={INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS}, author={Mirka, GA and Smith, C and Shivers, C and Taylor, J}, year={2002}, month={May}, pages={263–273} }
 @article{mirka_shivers_smith_taylor_2002, title={Ergonomic interventions for the furniture manufacturing industry. Part II - Handtools}, volume={29}, ISSN={["0169-8141"]}, DOI={10.1016/S0169-8141(01)00068-3}, abstractNote={The objectives of this intervention research project were to develop and evaluate engineering controls for the reduction of the upper extremity injury risk in workers in the furniture manufacturing industry. The analysis of OSHA Form 200 logs and surveys of furniture workers revealed that upholsterers, workers who use random orbital sanders and workers who use spray guns are at higher levels of risk of illness than the rest of the working population. An on-site ergonomic analysis of these three jobs was performed and the following risk factors were identified for each of these three work groups: upholsterers—repetitive, high-force pinch grips; sanders—long-duration static grip forces; and sprayers—awkward postures (ulnar wrist deviations and wrist flexion). Engineering interventions in the form of new or modified handtools were then evaluated in the laboratory to assess their effectiveness in reducing exposure to these risk factors. For sanding, an interface was created that secured the hand to the sander with the intention of reducing the need for static grip forces during sanding. A new handtool was created for upholsterers that replaced the repetitive pinch grips with a power grip. Finally, a commercially available spray gun with ergonomic features was evaluated. Each of these modified tools/methods was compared with the standard methods typically used in industry. The results show that most of the intended beneficial effects were realized. The random orbital sander interface reduced extensor muscle activities by an average of 30%. The upholstery handtool reduced the intrinsic hand muscle activities by an average of 51%. The effects of the adapted spray gun were most prominent when working on horizontal surfaces and showed an average reduction of 40° of wrist flexion and 14° of ulnar deviation as compared to the standard pistol grip spray gun in this activity. The ergonomic intervention research described in this report documents a reduction in exposure to risk factors for upper extremity cumulative trauma disorders for three work activities in the furniture manufacturing industry.}, number={5}, journal={INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS}, author={Mirka, GA and Shivers, C and Smith, C and Taylor, J}, year={2002}, month={May}, pages={275–287} }