Article

Surface EMG (sEMG) is routinely used in gait analysis laboratories to record
rectus femoris (RF) activity during gait. This is despite the fact that the
literature has suggested sEMG may be inaccurate for RF monitoring secondary to
its susceptibility to crosstalk from the neighboring vasti. If true, one might
expect this error to be exacerbated by crouch gait when vasti demand is elevated.
The purpose of this study was to investigate the impact of vasti crosstalk on RF
sEMG across a variety of speed (four) and crouch (four) combinations. A group of
20 able-bodied adults were studied walking in 16 different combinations of speed
and crouch while computerized gait analysis and EMG data were collected. RF EMG
activity was monitored using both surface and fine wire electrodes
simultaneously. Results showed that sEMG is affected by vasti crosstalk during
substantial portions of both stance and swing. At the two slowest speeds tested,
RF was not active at any point during the gait cycle, though sEMG suggested RF
activity during some to all of stance phase. Despite sEMG indicating otherwise,
true RF did not occur during loading response in any of the 16 conditions tested.
During crouch at the two fastest speeds, a burst of true RF activity occurred
during a short period of single limb stance, though sEMG incorrectly reflected RF
activity throughout stance. Vasti-to-rectus crosstalk also occurred regularly
during terminal swing. Surface EMG incorrectly suggests RF activity during
portions of both stance and swing secondary to vasti crosstalk. This may lead to
interpretation errors which could affect clinical recommendations.
CI - Copyright (c) 2010 Elsevier B.V. All rights reserved.

Langue : ANGLAIS