@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{lutz_starr_smith_stewart_monroe_joines_mirka_2001, title={The use of mirrors during an assembly task: a study of ergonomics and productivity}, volume={44}, DOI={10.1080/001401301750048222}, abstractNote={Industrial assembly tasks often require awkward, sustained neck and/or shoulder postures that can lead to increased musculoskeletal discomfort and reduced productivity. The aim of this study was to investigate the effects of mirror and periscope visual aids as ergonomic interventions designed to eliminate awkward postures of the cervicobrachial region during assembly tasks. Participants simulated a simple assembly task by using a cordless screwdriver to drive screws into a pre-tapped aluminium block. Trials of 15 min were run for each of four distinct assembly workstation configurations: industry standard (in-line screwdriver, work at elbow height, no visual aid); pistol grip (pistol grip screwdriver, work at shoulder height, no visual aid); mirror (in-line screwdriver, work at elbow height, single mirror visual aid); and periscope (in-line screwdriver, work at elbow height, two-mirror visual aid system). Muscular activity, discomfort, body posture, productivity and operator subjective assessment were recorded to determine the effects of the visual aid interventions. The results show that when comparing the interventions to the industry standard condition, there was a 45% reduction in average cervical erector spinae activity, a 90% reduction in average neck flexion angle and a 72% reduction in neck discomfort with the interventions. When comparing these interventions to the pistol grip condition there was an 80% reduction in activity of the dominant side deltoid, a 92% reduction in shoulder flexion angle and an 81% decrease in shoulder discomfort with the interventions. Productivity was greatest in the industry standard configuration followed by the pistol grip (9% lower), the periscope (13% lower) and the mirror (23% lower) configurations. A follow-up study that compared the productivity of the periscope configuration with that of the industry standard configuration showed that within a 4-h work period this productivity differential decreased by over 33%.}, number={2}, journal={Ergonomics}, author={Lutz, T. J. and Starr, H. and Smith, C. A. and Stewart, A. M. and Monroe, M. J. and Joines, S. M. B. and Mirka, G. A.}, year={2001}, pages={215–228} }