Open Access

ARTICLE

Quantitative Method for Biomechanical Evaluation of Bedding Comfortableness

by Akisue Kuramoto¹, Hitoshi Kimura², Norio Inou²

1 Tokyo Metropolitan University, Tokyo, 191-0065, Japan.
2 Tokyo Institute of Technology, Tokyo, 152-8550, Japan.

* Corresponding Author: Akisue Kuramoto. Email: .

Molecular & Cellular Biomechanics 2019, 16(4), 235-243. https://doi.org/10.32604/mcb.2019.08123

Abstract

Comfortable bedding is usually designed subjectively because of the difficulty in performing a quantitative evaluation. This paper proposes a quantitative evaluation method of comfortableness of beddings. The bedding shape determining how comfortable an individual may feel in using it depends on the body shape and normal posture of individuals. The internal physical load is expected to relate to the comfortableness of bedding. However, only a few quantitative discussions exist on the relation between the comfortableness of bedding and physical load. This study proposes a new evaluation method of physical load in a relaxed posture. The strain energy of muscles and joints was used as an indicator of physical load. To estimate physical load, a neutral body position was simulated from a natural standing posture and was used as a reference posture with the neutral condition of muscle lengths. By considering individual differences, multiple models of neutral body position were provided. We simulated individual differences of a comfortable pillow height using the proposed models. Physical load in a relaxed posture was varied according to the models. Calculated results show that physical load becomes small when a pillow is comfortable. For both subjective pillow comfortableness and smallness of physical load, there is a similar tendency that the low pillow with the small height difference between head and neck is preferable if the concave depth of back shape of head and neck is small. Moreover, the results show that muscles and joints equally affect the comfortableness of designed pillow. This implies that less total energy required for maintaining the posture contributes to pillow comfortableness.

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