Walking Instability in Constant Speed and Variable Speed Treadmill Walking Evaluated by the Maximum Lyapunov Exponent of Chaos Analysis

• Published in: Rigaku ryoho kagaku Vol. 34; no. 5; pp. 607 - 613
• Main Authors: KUROSAWA, Chihiro, SUGIYAMA, Masahito, YASUI, Takato, SUZUKI, Tomotaka, TSUCHIDA, Masayuki, YAMAGUCHI, Kuroudo, KAI, Yoshihiro, OTAKI, Shusuke, SUGAWARA, Kenichi
• Format: Journal Article
• Language: Japanese
• Published: Tokyo The Society of Physical Therapy Science 2019; Japan Science and Technology Agency
• Subjects: chaos; Fitness equipment; gait stability; treadmill; Walking
• ISSN: 1341-1667; 2434-2807; 2434-2807
• DOI: 10.1589/rika.34.607

[Purpose] We developed a variable-speed treadmill that could be controlled at any speed. The influence of walking tasks which involved continuously changing the walking speed using this equipment on the walking stability of the participants was evaluated using the maximum Lyapunov exponent of chaos analysis on the walking stability factor. [Participants and Methods] The participants were 22 healthy adults. They were divided into a variable-speed walking task group (n=11) and a constant-speed walking task group (n=11). Time course acceleration data of the trunk was measured and compared using the maximum Lyapunov exponent. [Results] The maximum Lyapunov exponent in the vertical direction showed a larger value during the changing walking speed task than the during constant speed task. [Conclusion] It was observed that walking instability was maintained in the 30 minutes in the changing walking speed task. It suggests that performance of this walking exercise helps acquisition of diversity in walking speed.