Predicting passenger seat comfort and discomfort on the basis of human, context and seat characteristics: a literature review.

This literature review focused on passenger seat comfort and discomfort in a human-product-context interaction. The relationships between anthropometric variables (human level), activities (context level), seat characteristics (product level) and the perception of comfort and discomfort were studied through mediating variables, such as body posture, movement and interface pressure. It is concluded that there are correlations between anthropometric variables and interface pressure variables, and that this relationship is affected by body posture. The results of studies on the correlation between pressure variables and passenger comfort and discomfort are not in line with each other. Only associations were found between the other variables (e.g. activities and seat characteristics). A conceptual model illustrates the results of the review, but relationships could not be quantified due to a lack of statistical evidence and large differences in research set-ups between the reviewed papers. Practitioner Summary: This literature review set out to quantify the relationships between human, context and seat characteristics, and comfort and discomfort experience of passenger seats, in order to build a predictive model that can support seat designers and purchasers to make informed decisions. However, statistical evidence is lacking from existing literature.

Effect of canopy shape on physical load when holding an umbrella.

The aim of the current study was to investigate the effect of the canopy shape of an umbrella on physical load when holding the umbrella in different circumstances. For this purpose, thirteen subjects participated in this study and muscle activity of seven muscles of the upper limb (including the forearm) was measured for 5 wind speeds (4, 5, 6, 7, 8 Bft) and two wind directions (front and side). From the results, it was seen that for the p50 value of the muscle activity, the umbrella with the asymmetric canopy required 62% and for the p90 value of the muscle activity 74% of the muscle activity, on average, over all wind speeds - compared to the traditional umbrella. Based on these results, we can conclude that the physical load of holding the traditional umbrella is significantly higher than holding the umbrella with the asymmetric canopy shape in windy conditions.

Sitting comfort and discomfort and the relationships with objective measures.

The concepts of comfort and discomfort in sitting are under debate. There is no widely accepted definition, although it is beyond dispute that comfort and discomfort are feelings or emotions that are subjective in nature. Yet, beside several subjective methodologies, several objective methods (e.g. posture analysis, pressure measurements, electromyography (EMG) are in use to assess sitting comfort or discomfort. In the current paper a theoretical framework is presented, in which comfort and discomfort were defined and the hypothetical associations with underlying factors were indicated. Next, the literature was reviewed to determine the relationships between objective measures and subjective ratings of comfort and discomfort. Twenty-one studies were found in which simultaneous measures of an objective parameter and a subjective rating of comfort or discomfort were obtained. Pressure distribution appears to be the objective measure with the most clear association with the subjective ratings. For other variables, regarding spinal profile or muscle activity for instance, the reported associations are less clear and usually not statistically significant.