A nonlinear analysis of movement variability: stability in a sit to a stand
Description
The human body is a complex system comprised of many parts that can coordinate in a variety of ways to produce controlled action. This creates a challenge for researchers and clinicians in the treatment of variability in motor control. The current study aims at testing the utility of a nonlinear analysis measure – the Largest Lyapunov exponent (1) – in a whole body movement. Experiment 1 examined this measure, in comparison to traditional linear measure (standard deviation), by having participants perform a sit-to-stand (STS) task on platforms that were either stable or unstable. Results supported the notion that the Lyapunov measure characterized controlled/stable movement across the body more accurately than the traditional standard deviation (SD) measure. Experiment 2 tested this analysis further by presenting participants with an auditory perturbation during performance of the same STS task. Results showed that both the Lyapunov and SD measures failed to detect the perturbation. However, the auditory perturbation may not have been an appropriate perturbation. Limitations of Experiment 2 are discussed, as well as directions for future study.
Date Created
The date the item was original created (prior to any relationship with the ASU Digital Repositories.)
2016
Agent
- Author (aut): Gibbons, Cameron T
- Thesis advisor (ths): Amazeen, Polemnia G
- Committee member: Amazeen, Eric
- Committee member: Brewer, Gene
- Publisher (pbl): Arizona State University