The control mechanisms used by the central nervous system to maintain posture during changes in the base of support are not well understood. Two components, one proactive and one reactive, have been shown to contribute to balance. However, the way in which these elements are utilized for the control process is not clear. Athletic training, particularly in sports which require well-defined controlled movements, positively impacts the control of posture. Few studies have addressed the contribution of dance training on postural control and these results were inconclusive. Thus, the present goal was to contrast dancer and non-dancer strategies for the maintenance of upright balance. This study assessed postural control during multi-directional voluntary (leg lifts) and involuntary (surface tilts) weight shifting. Eleven classical ballet dancers and nine matched athletic non-dancers were recruited. Each participant performed five blocks of fast leg lifts in ten directions and maintained stance during five blocks of surface tilting (10° at 53°/s) in eight directions. A six-camera VICON 512 imaging system was used to determine 3-D body movement (120 Hz). To establish muscle activation patterns, EMG from four right leg muscle pairs was recorded at 1080 Hz. Simultaneously, two AMTI force plates measured ground reaction forces (1080 Hz). Group differences were evaluated by analysis of variance and principal component analysis. These experiments showed that control system redundancy is reduced through the recruitment of specific postural strategies that are selected based on the task goal. Limb unloading, voluntary or unexpected, requires control of the total body center of mass. During voluntary leg lifts, dancers and non-dancers achieve this goal differently. Dancers maintain vertical trunk alignment whereas non-dancers use changes in trunk orientation to generate movement and control COM displacement. In contrast, surface tilting produced stereo
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.84261 |
| Date | January 2003 |
| Creators | Hughey, Lucinda Kay |
| Contributors | Fung, Joyce (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (School of Physical and Occupational Therapy.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 002209415, proquestno: AAINQ98276, Theses scanned by UMI/ProQuest. |
Page generated in 0.0023 seconds