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| 1 | <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 3.0//EN"> |
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| 2 | <!--Converted with LaTeX2HTML 96.1-h (September 30, 1996) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds --> |
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| 3 | <HTML> |
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| 4 | <HEAD> |
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| 5 | <TITLE>Relationship of Stride Dynamics to Height</TITLE> |
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| 6 | <META NAME="description" CONTENT="Relationship of Stride Dynamics to Height"> |
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| 7 | <META NAME="keywords" CONTENT="gait-reprint"> |
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| 9 | <META NAME="distribution" CONTENT="global"> |
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| 11 | </HEAD> |
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| 13 | <A NAME="tex2html108" HREF="node12.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="/icons/latex2html/next_motif.png"></A> <A NAME="tex2html106" HREF="node8.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="/icons/latex2html/up_motif.png"></A> <A NAME="tex2html102" HREF="node10.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="/icons/latex2html/previous_motif.png"></A> <BR> |
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| 16 | <B> Previous:</B> <A NAME="tex2html103" HREF="node10.html">Temporal Structure Measures</A> |
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| 17 | <BR> <P> |
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| 18 | <H3><A NAME="SECTION00040300000000000000">Relationship of Stride Dynamics to Height</A></H3> |
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| 19 | <P> |
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| 20 | In children, many aspects of gait depend on body size. For example, over |
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| 21 | certain age ranges, stride length increases linearly with age, but |
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| 22 | the relationship between stride length and age becomes constant after |
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| 23 | adjusting for height or leg length (2). |
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| 24 | Similarly, we observed a significant increase (p |
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| 25 | < .0001) in velocity in the 6 and 7 year old children (1.20 <IMG WIDTH=12 HEIGHT=27 ALIGN=MIDDLE ALT="tex2html_wrap_inline288" SRC="img6.png"> |
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| 26 | 0.03 m/sec) compared to the 3 and 4 year old children (1.00 <IMG WIDTH=12 HEIGHT=27 ALIGN=MIDDLE ALT="tex2html_wrap_inline288" SRC="img6.png"> 0.03 |
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| 27 | m/sec). However, relative velocity (velocity/height) was |
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| 28 | essentially identical in these two groups (p = 0.92). |
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| 29 | To begin to |
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| 30 | evaluate whether the changes in stride dynamics were only a function |
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| 31 | of changes in biomechanics related to growth, we normalized the dynamical |
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| 32 | measures with respect to height. In the present study, height |
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| 33 | increased linearly with age (r = 0.96; p < .0001). |
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| 34 | Variability is inversely related to age (Figure 3). Thus, we |
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| 35 | normalized the dynamical variables (either by appropriately dividing |
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| 36 | or multiplying by height) and re-examined the relationship with |
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| 37 | age. The age-dependence persisted when |
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| 38 | the measures of variability and dynamics were adjusted for height |
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| 39 | or if leg length was used instead of height as the normalizing factor. |
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| 40 | For example, the CV normalized with respect to leg length |
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| 41 | was 128 <IMG WIDTH=12 HEIGHT=27 ALIGN=MIDDLE ALT="tex2html_wrap_inline288" SRC="img6.png"> 10, 83 <IMG WIDTH=12 HEIGHT=27 ALIGN=MIDDLE ALT="tex2html_wrap_inline288" SRC="img6.png"> 5, and 67 <IMG WIDTH=12 HEIGHT=27 ALIGN=MIDDLE ALT="tex2html_wrap_inline288" SRC="img6.png"> 3 in the 3 and 4 year olds, 6 and 7 year olds, |
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| 42 | and in the 11 to 14 year olds, respectively. |
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| 43 | The difference between the 6 and 7 year olds and the 11 to 14 year olds was significant (p < .05). The CV in the 3 and 4 year old was significantly |
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| 44 | increased |
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| 45 | (p < .0005) compared to both older groups. |
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| 46 | <P> |
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| 47 | Finally, we note that consistent with previous findings (26) |
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| 48 | the average values of stride time and walking velocity were age-dependent. |
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| 49 | Mean stride time was 900 <IMG WIDTH=12 HEIGHT=27 ALIGN=MIDDLE ALT="tex2html_wrap_inline288" SRC="img6.png"> 14 msec in the 3 and 4 year olds, |
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| 50 | increased (p < .01) to 955 <IMG WIDTH=12 HEIGHT=27 ALIGN=MIDDLE ALT="tex2html_wrap_inline288" SRC="img6.png"> 12 msec in the 6 and 7 year olds, and |
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| 51 | increased further (p < .0001 ) in the 11 to 14 year olds (1072 <IMG WIDTH=12 HEIGHT=27 ALIGN=MIDDLE ALT="tex2html_wrap_inline288" SRC="img6.png"> 18 |
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| 52 | msec). Walking velocity was 1.00 <IMG WIDTH=12 HEIGHT=27 ALIGN=MIDDLE ALT="tex2html_wrap_inline288" SRC="img6.png"> 0.03 m/sec in the 3 and 4 year |
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| 53 | olds, 1.20 <IMG WIDTH=12 HEIGHT=27 ALIGN=MIDDLE ALT="tex2html_wrap_inline288" SRC="img6.png"> 0.03 m/sec in the 6 and 7 year olds, and 1.28 <IMG WIDTH=12 HEIGHT=27 ALIGN=MIDDLE ALT="tex2html_wrap_inline288" SRC="img6.png"> |
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| 54 | .0.03 m/sec in the 11 to 14 year olds. The difference between the |
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| 55 | youngest and two older groups was significant (p < .0001); however, walking velocity |
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| 56 | was not significantly different in the 6 and 7 year olds and the 11 to |
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| 57 | 14 year olds. |
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| 58 | <P> |
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| 60 | <B> Next:</B> <A NAME="tex2html109" HREF="node12.html">Discussion</A> |
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| 61 | <B>Up:</B> <A NAME="tex2html107" HREF="node8.html">Results</A> |
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| 62 | <B> Previous:</B> <A NAME="tex2html103" HREF="node10.html">Temporal Structure Measures</A> |
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