• Journal of the Ergonomics Society of Korea
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• v.34 no.2
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• pp.151-165
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• 2015

Objective: This study aims to develop and scientifically investigate the efficacy of the Spine S-curve Reactive Backrest that responds to the spine curvature of the user when seated, and maintains and enhances the natural S-curve of the lower back, thereby helping to relieve fatigue, correct posture and prevent spine deformities. Background: The focus of current development, design guidelines and/or standards for office chairs is mainly placed on the chair's dimensions, incline angle, adjusting features and lumbar support. Research and development was called for developing a chair backrest that maintains and improves the S-curve of the full spine. Method: The Spine S-curve Reactive Backrest was ergonomically designed to maintain correct posture and enhance user comfort. When leaned on, the backrest responds to the user's spine line and the whole lower back sits closely against the backrest, thereby aligning the user's lower back and backrest as one to maintain and improve the natural S-curve formation of the spine. In order to evaluate the efficacy of the newly designed chair (new design) and the comparison target (chair), five male college students of standard body type with normal spine curvature were selected as test subjects, and a motion analyzer and electromyography were utilized to measure S-curve and erector spinae muscle activity when seated. Results: The spine S-curve was better maintained and improved when sitting in the new design than in the comparison chair. Particularly notable was the greater displacement gap of the thoracic spine than the cervical spine, and also that of the lumbar more than the thoracic spine, with the increase of the backrest tilting angle. Furthermore, the electromyogram results showed the new design caused a lower fatigue level of the erector spinae muscles compared to the comparison chair, and also earned a higher preference in the subjective opinion results. Conclusion: The newly designed chair in this study responds to the user's spine curvature and maintains and enhances the lower back's natural S-curve, and thereby relieves fatigue, promotes better posture, and helps to prevent spine deformities better than existing office chairs. There is a need to widely introduce and supply this new design. Application: The new design is applicable to office and student chairs, and is expected to improve concentration and work efficiency.

• Journal of the Korea Convergence Society
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• v.5 no.4
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• pp.61-68
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• 2014

In the present study, we aimed to examine the effects of Schroth exercise(three-dimensional convergence exercise) on pulmonary function(vital capacity, and chest expansion), Cobb's angle, scoliometer angle, and erector spinae muscle activity. We examined 40 students with idiopathic scoliosis(Cobb's angle $10^{\circ}$). They were divided into the Schroth and conventional exercise groups, with 20 people in each group. Statistical analysis was performed by using SPSS 18.0 with a paired t-test(pre-post difference) and an independent t-test(between-group differnence). the result of were as follows; 1) After 8 weeks of Schroth exercise, significant improvements were observed in Cobb's angle, rib hump, vital capacity, chest expansion, and right thoracic longissimus muscle activity. 2) After 8 weeks of conventional exercise, a significant improvement was observed only in chest expansion. These findings indicate that the Schroth exercise program improved the Cobb's angle, rib hump, pulmonary function, and sEMG results. Therefore, this study demonstrates the usefulness of the Schroth exercise program for idiopathic scoliosis.