Ergonomics
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To examine the effects of firefighters' self-contained breathing apparatus' (SCBA) weight and its harness design on the physiological and subjective responses, eight male students performed treadmill exercise under four conditions: the 8 kg firefighter protective clothing (PC) (Control), the PC + an 11 kg SCBA with an old harness (Test A), the PC + a 6.4 kg SCBA with an old harness (Test B) and the PC + a 6.4 kg SCBA with a new harness (Test C), at ambient temperatures (T(a)) of 22°C and 32°C. Besides highlighting the fact that a heavy SCBA had a significant effect on the oxygen consumption and metabolic rate, this experiment also found that in a T(a) of 32°C, in particular, the combined effect of 4.7 kg lighter SCBA and new harness design could reduce metabolic rate and improved subjective muscle fatigue and thermal discomfort. ⋯ An effort to alleviate the physiological and subjective burden of firefighters by reducing the weight of SCBA and by using the new harness design has provided satisfactory results in reduced oxygen consumption and in improved subjective responses in a hot air environment.
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Factors, such as high repetition, high force and gripping play a role in the development of upper extremity work-related musculoskeletal disorders. The purpose of this study was to systematically examine the effects of push load and frequency on muscle activity with and without concurrent gripping. A total of 10 men and 10 women performed a cyclic bimanual pushing task. All combinations of three push loads (1 kg, 2 kg, 4 kg), three frequencies (4/min, 8/min, 16/min) and two grip conditions (no required grip and 30% of maximum grip force) were performed in randomised order. The muscle activity of the upper arm and shoulder complex reflected both frequency and load, often with significant interactions, thus may be better described by workload, the product of force and frequency. In the forearm, muscle activities were generally low but adding a submaximal grip superseded the effects of push load, with the activity reflecting frequency and grip. ⋯ Force and frequency are important risk factors for upper extremity disorders. We found that upper extremity muscle activity responds to workload (force × frequency) in a complex way which may be superseded if a grip is present. This electromyographic study provides physiological insights to muscular loading as basis for a variety of workplace disorders.
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Numerous studies have demonstrated how temperature can affect perceptual, cognitive and psychomotor performance (e.g. Hancock, P. A., Ross, J., and Szalma, J., 2007. ⋯ Furthermore, important implications for services, retail and other settings of interpersonal interactions are discussed. Practitioner Summary: Temperature effects on performance have emerged as a vital research topic. Owing to services' increasing economic importance, we transferred this research to the construct of customer orientation, focusing on performance in service and retail settings. The demonstrated temperature effects are transferable to services, retail and other settings of interpersonal interactions.
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Work-related musculoskeletal pain (MSP) risk assessments by trained observers are often used in ergonomic practice; however, the validity may be questionable. We investigated the predictive value of work-site MSP risk estimates in a prospective cohort study of 1745 workers. Trained observers estimated the risk of MSP (neck, shoulder or low-back pain) using a three-point scale (high, moderate and low risk) after observing a video of randomly selected workers representing a task group. ⋯ The results show that observers were able to estimate the risk of shoulder and neck pain, whereas they found it difficult to estimate the risk of low-back pain. Practitioner Summary: Work-related musculoskeletal pain risk assessments by observers are often used in ergonomic practice. We showed that observers were able to estimate shoulder and neck pain risk, but had difficulties to estimate the risk of low-back pain. Therefore, observers' risk estimates might provide a useful method for musculoskeletal pain risk assessments.
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Although adaptive coordination has been highlighted by several studies, research dealing with how adaptive coordination develops is still rare. Thus, the aim of this study was to investigate the development of coordination mechanisms and their task-related adaptation in a longitudinal observation of medical simulation-based training of final year students. We recorded six anaesthesia teams during a sequence of four task scenarios, and each scenario comprised of a routine and a complication phase. After trained observers rated sub-tasks within each scenario for explicit and implicit coordination, statistical analysis revealed a statistically significant effect of previous scenarios on coordination development in the routine phases. While the amount of explicit coordination decreased, implicit coordination increased, revealing adaptive coordination as a skill developed through repeated group interaction. We conclude that anaesthesia training should consider cost- and patient safety-benefits of implicit and explicit coordination and focus on adaptive coordination. ⋯ Group coordination is crucial to anaesthesia team performance. Results of this longitudinal observation of six anaesthesia teams during four medical simulation-based training scenarios document that teams develop adaptive patterns of coordination. This study also demonstrates that adaptive coordination is a trainable skill within crisis resource management training.