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Postural Coordination During Quiet Stance and Suprapostural Activity

Smith, Dean L

Abstract Details

2004, Doctor of Philosophy, Miami University, Psychology.
Coordination of joints has not been well studied during quiet stance or non-locomotive suprapostural activity. This dissertation consists of three experiments examining multi-segmental postural coordination. Experiment 1, tested the effect of vision and support surface on multi-segmental postural kinematics and joint angles during upright quiet stance. Eight participants stood still on four surfaces (flat, foam surface, foam roller, wood beam) with eyes open and closed. Postural motion was recorded by an electromagnetic tracking device from the head, trunk, sacrum, hip, knee and ankle. Overall postural (head) sway and joint motion was influenced by both surface of support and vision. More sway and sagittal joint rotation occurred under non-visual and non-flat conditions. An ankle strategy as opposed to a hip strategy is primary in maintaining voluntary, upright balance on non-flat surfaces. In experiments 2 and 3, surface of support (hard surface vs. foam roller) and suprapostural task (head-tracking frequency) were manipulated simultaneously. Twelve different participants in each experiment stood on each surface with hands behind their back looking at a computer monitor in front of them. They were instructed to maintain balance while tracking a simulated oscillating (fore-aft) computer target with their head at different frequencies. In Experiment 2, a rest was given between trials (frequencies), whereas no rest was given between trials in Experiment 3. The effects of discrete (rest), and changing frequency modulation (no rest) on postural dynamics were then determined. Results demonstrate that people use a continuum of coordination strategies to accomplish head-tracking at different frequencies. On both surfaces, a predominantly anti-phase, hip-ankle relationship was seen with only gradual postural transitions observed. Dynamic standing tasks exhibit many similarities in postural coordination whether performed at a singular frequency or by modulating frequency. However, continuous motion without rest may confer postural stability benefits when compared to discrete frequency oscillation. The results imply that models of postural control should be explicitly multi-segmental, that postural transitions are gradual during suprapostural activity, and that modulating postural frequency may confer stability benefits. Most importantly, the data strongly argue that there is a need to examine postural control and coordination without mechanical perturbation.
Leonard Smart (Advisor)
100 p.

Recommended Citations

Citations

  • Smith, D. L. (2004). Postural Coordination During Quiet Stance and Suprapostural Activity [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1091063392

    APA Style (7th edition)

  • Smith, Dean. Postural Coordination During Quiet Stance and Suprapostural Activity. 2004. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1091063392.

    MLA Style (8th edition)

  • Smith, Dean. "Postural Coordination During Quiet Stance and Suprapostural Activity." Doctoral dissertation, Miami University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=miami1091063392

    Chicago Manual of Style (17th edition)