ABSTRACT

Objective: This study aimed at the development and validation of a spine curvature responsive chair backrest that helps maintain the correct posture and relieve back fatigue by facilitating and enhancing the natural spine curve in response to the shape of the spine while the chair back embraces the user’s back when seated. Methods: The spine curvature responsive backrest was designed to be attached to a general office chair. When the user leans on his or her back, the back responds according to the user’s spine curvature such that the entire back is closely stuck to the backrest, thereby maintaining and improving the natural curve of the spine. Ten male college students were selected as the subjects, and the change in their spinal curvature was measured using a motion analyzer and an EMG. Results: The results of a motion analyzer evaluation showed that the lordosis of the lumbar and the kyphosis of the thoracic vertebrae increased as the reclining angle increased to 125 degrees, starting from the backrest angle of 105 degrees when using the developed backrest. As the results of the EMG evaluation, the post-median frequency was higher than the pre-median frequency at all backrest angles. Conclusion: The spine curvature responsive backrest developed in this study helps to maintain a proper posture when seated, thereby relieving tension in the back muscles. It can be used as a chair for office workers and students who sit for a long period of time for reducing their back fatigue.