Article

Appropriate muscular response following an external perturbation is essential in
preventing falls. Transtibial prosthesis users lack a foot-ankle complex and
associated sensorimotor structures on the side with the prosthesis. The effect of
this lack on rapid responses of the lower limb to external surface perturbations
is unknown. The aim of the present study was to compare electromyogram (EMG)
response latencies of otherwise healthy, unilateral, transtibial prosthesis users
(n = 23, mean +/- standard deviation [SD] age = 48 +/- 14 yr) and a matched
control group (n = 23, mean +/- SD age = 48 +/- 13 yr) following sudden
support-surface rotations in the pitch plane (toes-up and toes-down).
Perturbations were elicited in various weight-bearing and limb-perturbed
conditions. The results indicated that transtibial prosthesis users have delayed
responses of multiple muscles of the lower limb following perturbation, both in
the intact and residual limbs. Weight-bearing had no influence on the response
latency in the residual limb, but did on the intact limb. Which limb received the
perturbation was found to influence the muscular response, with the intact limb
showing a significantly delayed response when the perturbation was received only
on the side with a prosthesis. These delayed responses may represent an increased
risk of falling for individuals who use transtibial prostheses.

Langue : ANGLAIS