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Impaired regulation post-stroke of motor unit firing behavior during volitional relaxation of knee extensor torque assessed using high density surface EMG decomposition. Annu Int Conf IEEE Eng Med Biol Soc 2015;2015:4606-9

Date

01/07/2016

Pubmed ID

26737320

Pubmed Central ID

PMC5073378

DOI

10.1109/EMBC.2015.7319420

Abstract

The purpose of this study was to use high density surface EMG recordings to quantify stroke-related abnormalities in motor unit firing behavior during repeated sub-maximal knee extensor contractions. A high density surface EMG system (sEMG) was used to record and extract single motor unit firing behavior in the vastus lateralis muscle of 6 individuals with chronic stroke and 8 controls during repeated sub-maximal isometric knee extension contractions. Paretic motor unit firing rates were increased with subsequent contractions (6.19±0.35 pps vs 7.89±0.66 pps, P <; 0.05) during task phases of torque decline as compared to controls (6.95±0.40 pps vs 6.68±0.41 pps). In addition, corresponding rates of torque decline were decreased for the paretic leg as compared to the non-paretic leg. These results suggest that regulation of declining forces may be impaired post stroke due to prolonged firing of paretic motor units.

Author List

Murphy SA, Berrios R, Nelson PA, Negro F, Farina D, Schmit B, Hyngstrom A

Authors

Allison Hyngstrom PhD Associate Professor in the Physical Therapy department at Marquette University
Brian Schmit PhD Professor in the Biomedical Engineering department at Marquette University




MESH terms used to index this publication - Major topics in bold

Electromyography
Humans
Isometric Contraction
Knee
Muscle, Skeletal
Stroke
Torque