Posture, Pressure, and Muscle Activation Pattern of Adolescent with Idiopathic Scoliosis in Static and Dynamic Sitting

In this study, we evaluated the influence of idiopathic scoliosis on postural balance and muscle activity in static and dynamic sitting condition. Twelve adolescents with idiopathic scoliosis were included in this study. Postural balance and muscle activities of all subjects were assessed under two experimental conditions: i) static sitting, ii) dynamic sitting. In static sitting condition, subjects were instructed to sit the board for 30 seconds. In dynamic sitting condition, subjects performed pelvic anterior, posterior, left, right tilting induced by the structure of the board for 5 seconds, respectively. Inclination angle was measured by accelerometer which was attached to the center of the unstable board. Body pressure distribution pattern (contact area, maximum force, peak pressure, and mean pressure) was analyzed using capacitive seat sensor system. Also, surface electrodes were attached to the thoracic erector spinae, lumbar erector spinae, lumbar multifidus, and external oblique for assessing muscle activity. In comparison with mean inclination angle and pressure distribution between left and right side, postural balance was tilted to the posterior and left side. In addition, erector spinae muscles, especially thoracic erector spinae muscle, of subjects with AIS more increased on right side than left side in dynamic sitting condition. From these results, we confirmed that idiopathic scoliosis cause postural asymmetry, unequal balance, and muscular imbalance in static and dynamic sitting. Furthermore, postural balance measurement system in this study can be utilized to detect asymmetric sitting posture and abnormal muscle activity caused by idiopathic scoliosis. WSEAS TRANSACTIONS on BIOLOGY and BIOMEDICINE Ji-Yong Jung, In-Sik Park, Yonggwan Won, Bong-Ok Kim, Soo-Kyung Bok, Jung-Ja Kim E-ISSN: 2224-2902 118 Volume 11, 2014 Key-Words: Adolescent idiopathic scoliosis, postural balance, body pressure, muscle activity, static sitting, dynamic sitting, unstable board.