本研究的目的在於以一個可以保有大軀幹-與-大腿夾角的概念來設計通用椅，以降低肌肉骨骼應力負荷。通用椅泛指用於上課、辦公和餐廳等的椅子類型，為我們日常生活最常接觸的椅子。當人坐於傳統通用椅時，我們上身與大腿呈現90度的夾角，這個角度會造成肌肉骨骼組織的持續應力負荷。過去研究指出，當我們上身與大腿夾角增大時，則肌肉骨骼的應力負荷隨之降低。基於這個概念，本研究提議一種新型通用椅的設計型式，以增大上身與大腿的夾角，降低應力負荷。
　　新型通用椅的設計概念是將椅面提高，使大腿向下傾斜，並搭配後傾25度的調整式椅背。此新型通用椅將椅面區分為前後兩段，前段向下傾斜20度作為預防大腿下軟組織壓迫的大腿支撐面，後段水平坐面用以穩固支撐臀部。
請10位男性受試者來進行實驗量測新型通用椅所需的三個尺寸，椅面的高度藉由人體計測資料庫計算出大腿向下傾斜20度所產生的高度作為設計尺寸、後段水平坐面以臀溝至臀部後側作為設計尺寸、前段向下傾斜支撐面的長度以臀溝至膝窩的1/3長度作為設計尺寸。
　　實驗結果得到水平坐面深度為21公分、向下傾斜支撐面長度為10公分、椅面高度為55公分。新型通用椅能讓使用者由傳統通用椅90度夾角坐姿提升至110度夾角，並在使用椅背時增加至135度，此135度也是Keegan所說的自然姿勢，因此這種新型通用椅能使身體夾角提升，降低肌肉骨骼應力負荷。

The purpose of this study is to propose an ergonomic concept in preserving a large torso-to-thigh angle for the design general-purpose chairs, aiming at lowering musculoskeletal stresses. General-purpose chairs are the chairs we use most daily, like office chair, dinning chair and so forth. When we are sitting on the chair, a 90 degree torso-to-thigh angle will result in significant adverse musculoskeletal stresses in various body tissues. Nevertheless, past research found that the musculoskeletal stresses decreased as the torso-to-thigh angle 135 degree. Therefore, based on this finding, it is proposed that a chair be configured in maintaining a large torso-to-thigh angle for lower musculoskeletal stresses.
　　The new chair configuration is to raise the height of the seat-pans to pose the
thigh in a 20 degree downward, and assisted by a 25 degree slanted backrest, a seated man is able to maintain a large torso-to-thigh angle, up to135 degree The seat-pan must be configured as consists of two sections, a rear horizontal and a front slanted. The former is used to support upper body without shear force, and the latter is to support the underside of the thigh without tissue compression.
　　To design the chair, 3 key measurements must be obtained: seat height, depth of the rear section, and the length of the front section. The seat height is derived from anthropometrical data while the thigh is assumed at a 20 degree downward posture. The depth of rear horizontal section was determined by the distance between the gluteal fold and the posterior aspect of the buttocks. The depth of front slanted was determined by the 1/3 distance between the gluteal fold and popliteal. Ten young male students were recruited as subjects for these 3 measurements.
　　The results show that the height of seat-pan is 55cm; the depth of horizontal seat-pan is 21 cm; and the depth of thigh support is 10cm. When we are sitting on this new chair, our torso-to-thigh angle will be larger than general purpose chair about 20 degree. And torso-to-thigh angle will be 135 degree when leaning on back-support. This 135 degree is the neutral posture named by Keegan. The new chair will increase torso-to-thigh angle, and decrease musculoskeletal stress.

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