Age-Related Differences in Stepping Response When Stepping onto a Known Soft Surface under Dual Task Conditions

<table>An example of step response data. From top to bottom: Tap cue on back of heel; COP<svg height="7.1624999" id="M16" style="vertical-align:-0.11285pt" version="1.1" viewbox="0 0 8.7250004 7.1624999" width="8.7250004" xmlns="http://www.w3.org/2000/svg">
<g transform="matrix(1.25,0,0,-1.25,0,7.1625)">
<g transform="translate(72,-66.27)">
<text transform="matrix(1,0,0,-1,-71.95,66.44)">
<tspan style="font-size: 12.50px; " x="0" y="0">𝑥</tspan>
</text>
</g>
</g>
</svg> = Mediolateral center of pressure; <svg height="10.475" id="M17" style="vertical-align:-0.11285pt" version="1.1" viewbox="0 0 18.375 10.475" width="18.375" xmlns="http://www.w3.org/2000/svg">
<g transform="matrix(1.25,0,0,-1.25,0,10.475)">
<g transform="translate(72,-63.62)">
<text transform="matrix(1,0,0,-1,-71.95,63.79)">
<tspan style="font-size: 12.50px; " x="0" y="0">𝐹</tspan>
<tspan style="font-size: 12.50px; " x="7.7268538" y="0">𝑥</tspan>
</text>
</g>
</g>
</svg> =  Ground reaction force in lateral direction; <svg height="13.1875" id="M18" style="vertical-align:-2.29482pt" version="1.1" viewbox="0 0 17.5375 13.1875" width="17.5375" xmlns="http://www.w3.org/2000/svg">
<g transform="matrix(1.25,0,0,-1.25,0,13.1875)">
<g transform="translate(72,-61.45)">
<text transform="matrix(1,0,0,-1,-71.95,63.79)">
<tspan style="font-size: 12.50px; " x="0" y="0">𝐹</tspan>
<tspan style="font-size: 12.50px; " x="7.7268538" y="0">𝑦</tspan>
</text>
</g>
</g>
</svg> = Ground reaction force in anteroposterior direction; <svg height="10.55" id="M19" style="vertical-align:-0.17555pt" version="1.1" viewbox="0 0 17.5875 10.55" width="17.5875" xmlns="http://www.w3.org/2000/svg">
<g transform="matrix(1.25,0,0,-1.25,0,10.55)">
<g transform="translate(72,-63.56)">
<text transform="matrix(1,0,0,-1,-71.95,63.79)">
<tspan style="font-size: 12.50px; " x="0" y="0">𝐹</tspan>
<tspan style="font-size: 12.50px; " x="7.7268538" y="0">𝑧</tspan>
</text>
</g>
</g>
</svg> = Vertical ground reaction force. The stepping task was divided into four phases: (1) the initiation phase (I) was calculated from the tap cue to the onset (OT); (2) the preparatory phase (P) was calculated from OT to foot-off for the right leg (rFO); (3) the swing phase (S) was calculated from rFO to foot-contact for the right leg (rFC); (4) the double-stance  stance phase (D) was calculated from rFC to foot-off for the left leg (lFO).</table>

Current Gerontology and Geriatrics Research

fig1

Figure 1

Figure 1: Age-Related Differences in Stepping Response When Stepping onto a Known Soft Surface under Dual Task Conditions 