The spine, which is the connection between the upper and lower extremities, plays a critical role to keep balance and correct posture. Maintaining good posture is essential to provide normal biomechanical function of the body in daily life while bad posture can cause imbalanced muscle activation, joint stress, inefficient motion, and pain.
Until now, many studies that can help to prevent various spinal diseases by correting wrong posture and improving postural balance have been conducted. Although previous studies have reported the positive effects of some specific exercises therapy on improving the posture, balance stability, muscular strengthening in static and dynamic conditions, there are some limitations such as the sustainability in exercise and high expense of hiring a personal trainer for maintaining correct posture during exercises. To solve these problems, various exercise treatment devices are being developed. However, there is no exercise system which can relieve tension in the lower back and trunk as well as increase muscle strength on the weaker side.
Therefore, in this study the complex exercise system with MR damper was developed to stretch asymmetrical trunk and strengthen the weak erector spine muscles caused by poor sitting posture. 10 students with habitual bad posture during prolonged sitting were recruited from a university. The posture asymmetry of all subjects in static and dynamic sitting were analyzed, and then they were instructed to perform exercise program using the developed complex exercise system. To evaluate the effect of the developed system on improvement of postural correction, the body pressure distribution and trunk muscle activity during static and dynamic conditions were compared between before and after exercising. From the results, the differences in the body pressure distribution between the predominant and non-predominant side were reduced significantly after exercising with complex exercise system. In addition, the significant differences in the activity of erector spine muscle between the two sides decreased by increasing muscle strength on the weak side. Therefore, the developed complex exercise system with MR damper could be utilized to improve the postural balance and trunk stability of patients in various fields of rehabilitation medicine.