Purpose: This study investigated whether there is a correspondence between linear and non-linear analysis for postural stability. Specifically, the focus on this study was to examine whether standard deviation could represent postural stability of whole body and each foot. Methods: 12 young adults participated in the experiment and had to maintain their balance with eyes open in 5 postures: side-by-side (SS), staggered (left (SL) or right (SR) foot forward), and tandem (left (TL) or right (TR) foot forward). Each subject had two 65s trials in each condition. Under two force platform protocol, center of pressure of left (COPL) and right (COPR) was measured and total body center of pressure (COPNET) was finally measured in both the anterior-posterior (AP) and medio-lateral (ML) direction. Standard deviation (SD) of linear analysis and the largest Lyapunov expoenent (LyE) of non-linear analysis were measured for COPL, COPR, and COPNET across whole standing conditions. Results: SD of COPNET was larger in AP than ML in SR and SL conditions, whereas LyE of COPNET in AP and ML were not significantly different. In addition, SD of COPNET in AP was not significantly different from that in ML in TR and TL conditions, while LyE of COPNET in ML was larger than that in AP. Lastly, SD of COPL and COPR in ML was larger than that of COPR and COPL in TR and TL condition, respectively, on the other hand, there was no difference in LyE between COPL and COPR in ML in those conditions. Conclusion: Overall, there is an inconsistency between the SD and LyE during postural dynamics. The findings support the position that SD is not a representative measure of postural stability.

I. 서 론
 Ⅱ. 연구방법
  1. 연구대상
  2. 실험도구
  3. 실험 과제 및 절차
  4. 자료 처리
 Ⅲ. 결 과
  1. COP 궤적(trajectory)
  2. 가변성과 안정성
 Ⅳ. 논의 및 결론
 참고문헌

• 고지현(펜실베니아 주립대학교 운동과학과) | Ji-Hyun Ko (Department of Kinesiology, University Park, USA, Pennsylvania State University)
• 한동욱(전북대학교 스포츠과학과) | Dong-Wook Han (Department of Sport Science, Chonbuk National University) Corresponding author