The National Safety Council listed falls as the third ranked cause (14.6%) of unintentional deaths in the general population of the US. It is postulated that an attempt to control the COM is employed to prevent falls during perturbed gait. The goal of this research was to gain an understanding of (1) the relationship between COM dynamics at slip initiation and slip severity, and (2) how individuals control their COM dynamics when warned about the possibility of slipping (anticipatory control). The dynamics of the bodys COM during slips may reveal insights into the biomechanical reasons behind the high prevalence of slip-precipitated falls in the elderly. The findings may also be helpful in differentiating between postural strategies that successfully recover balance and responses that result in falls.
Sixteen healthy young (20-35 yrs) and 11 older (55-70 yrs) subjects were exposed to an unexpected slip (no prior knowledge of the floors contaminant condition), and alert slip (warned of the potential contamination), and known slip after two baseline walking trials. Body motion from 79 VICON markers attached to the body was sampled at 120 Hz. Segmental mass was generated using a segmental analysis. For an unexpected slip, maintaining the COM closer to the leading leg, an elevated COM position and fast medial-lateral COM transfers to the slipping leg at heel contact were associated with an increase in slip severity. For anticipation conditions (alert and known), COM placement and velocity was geared toward continuing the gait cycle. Age was significant in regards to COM position variables.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-07252005-220929 |
| Date | 14 October 2005 |
| Creators | Margerum, Sarah Elizabeth |
| Contributors | Richard Debski, Mark Redfern, Jean McCrory, Rakie Cham |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-07252005-220929/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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