Ergonomics
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This report presents the results of an ergonomics investigation into human thermal comfort using an automobile seat heated with an encapsulated carbonized fabric (ECF). Subjective and objective thermal comfort data were recorded while participants sat for 90 min in a heated and a non-heated automobile seat in an environmental chamber. Eight male participants each completed eight experimental sessions in a balanced order repeated measures experimental design. ⋯ Hand and foot comfort, sensation and temperature were similar in both seats. Asymmetric torso and thigh skin temperatures were higher in the heated seat although no significant discomfort was found in the front and back of the torso and thigh in either seat. Participants reported no significant difference in alertness between the control and heated seat.
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The purpose of this study was to examine the relationship between ratings of perceived exertion (RPE) and activity intensity, as determined by heart rate. Fifteen participants completed a standardized treadmill protocol in order to establish a heart rate--RPE calibration profile. These participants then completed two simulated occupational tasks--box carrying and sweeping. ⋯ There was a moderate, but statistically significant, correlation between monitored heart rate and heart rate predicted from RPE scores for both the box carrying (r = 0.70) and sweeping (r = 0.73) simulations. Direct prediction of task heart rate from RPE reported during the task was not as strongly correlated for the box carry (r = 0.11), as it was for the sweeping activity (r = 0.68). Results from this study suggested that heart rate monitoring alone does not account for enough of the variability resulting from both local and central mediation of RPE.