Faster walking speeds increase local instability among people with peripheral ne

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J Biomech. 2008 Aug 13.

Faster walking speeds increase local instability among people with

peripheral neuropathy.

Manor B, Wolenski P, Li L.

Department of Kinesiology, Louisiana State University, 112 Long

Fieldhouse, Baton Rouge, LA 70803, USA.

Individuals with peripheral neuropathy (PN) may compensate for

decreased somatosensation by reducing walking speed. Predisposition

to falls may therefore arise from an inability to adapt to

challenging walking speeds.

The purpose of this study was to examine the effects of PN on the

magnitude of variability and local instability on walking at

different speeds.

Twelve individuals with PN and 12 controls completed a 6-min walk

test to determine fast walking speed (FWS). Sagittal plane hip, knee,

and ankle joint angles were then calculated during 3min of treadmill

walking at 100%, 80%, and 60% FWS. The magnitudes of stride duration

variability (SDvar), joint angle variability (JTvar), and both short-

and long-term Lyapunov exponents (used to estimate local instability)

were calculated.

The PN group walked slower than the control group (p<.001). With

groups combined, walking faster led to increased local instability

and increased variability (p<.001). The PN group exhibited increased

variability (SDvar, p=.02; JTvar, p=.01) over all speeds, and

exaggerated local instability (p<.05) when walking at the fastest

speed.

PN leads to increased walking variability and local instability,

particularly when walking at challenging speeds. These results are

important to consider in future patient education and rehabilitation

programs.