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<TITLE>Introduction</TITLE> |
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<BR> <P> |
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<H1><A NAME="SECTION00020000000000000000">Introduction</A></H1> |
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<P> |
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When young children first begin to walk, immature control of posture |
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and gait results in large |
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stride-to-stride fluctuations and frequent falls (5,23). By |
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about three years of age, gait is relatively mature (26) and the |
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visually apparent unsteadiness has been replaced by a more stable walking |
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pattern. Nonetheless, |
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subtle changes in the development of neuromuscular control and |
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locomotor function continue well beyond age |
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three (2,19,23,25,26). |
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Some studies suggest a decrease in walking variability |
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after this age (21,24). However, a key unanswered question is |
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whether subtle changes in gait |
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unsteadiness and stride-to-stride dynamics also occur beyond this age. |
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<P> |
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Even in healthy, young adults, the gait cycle duration -- the stride |
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time -- fluctuates from one stride to the next in an apparently |
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random, noisy manner (11,16). However, in young adults with |
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intact neural control, the magnitude of these fluctuations is |
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relatively small. Although the stride-to-stride changes |
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appear to fluctuate randomly with no correlation between present and |
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future stride times, the healthy adult locomotor system actually |
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possesses ``memory'' such that the change from one stride to the next |
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displays a subtle, ``hidden'' temporal structure that has been |
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associated with long-range, fractal organization (11,12). In |
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contrast, in persons with neurological disease and in older persons, |
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especially those with a history of falls, stride-to-stride |
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variability increases and the temporal organization of stride time |
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dynamics is altered as well (3,4,7,8,10,14). |
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<P> |
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These studies suggest that analysis of the stride time dynamics may |
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also provide a window into the development of neuromuscular |
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control in children. Given the apparent parallels between the immature |
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gait of children and the unsteady gait of older persons and |
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persons with neurological impairment (23), |
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along with the subtle continued development of neural control beyond age three, we hypothesized |
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that |
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stride time dynamics will not be fully matured at this age. In the |
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present study, we tested this hypothesis by measuring |
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stride-to-stride fluctuations in the gait cycle duration of healthy |
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children 3 to 14 years of age. More specifically, we sought: i) to |
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characterize the development of mature stride dynamics, ii) to |
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determine at what ages changes in gait dynamics occur, and iii) |
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to compare the gait dynamics of children to those of adults. |
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<P> |
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