Imperial College London
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ProfessorDarioFarina

Faculty of Engineering, Department of Bioengineering

Chair in Neurorehabilitation Engineering
 
 
 
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Contact

 

+44 (0)20 7594 1387d.farina Website

 
 
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Location

 

RSM 4.15Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Murphy:2019:10.3389/fphys.2019.00545,
author = {Murphy, S and Durand, M and Negro, F and Farina, D and Hunter, S and Schmit, B and Gutterman, D and Hyngstrom, A},
doi = {10.3389/fphys.2019.00545},
journal = {Frontiers in Physiology},
title = {The relationship between blood flow and motor unit firing rates in response to fatiguing exercise post-stroke},
url = {http://dx.doi.org/10.3389/fphys.2019.00545},
volume = {10},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - We quantified the relationship between the change in post-contraction blood flow with motor unit firing rates and metrics of fatigue during intermittent, sub-maximal fatiguing contractions of the knee extensor muscles after stroke. Ten chronic stroke survivors (>1-year post-stroke) and nine controls participated. Throughout fatiguing contractions, the discharge timings of individual motor units were identified by decomposition of high-density surface EMG signals. After five consecutive contractions, a blood flow measurement through the femoral artery was obtained using an ultrasound machine and probe designed for vascular measurements. There was a greater increase of motor unit firing rates from the beginning of the fatigue protocol to the end of the fatigue protocol for the control group compared to the stroke group (14.97 ± 3.78% vs. 1.99 ± 11.90%, p = 0.023). While blood flow increased with fatigue for both groups (p = 0.003), the magnitude of post-contraction blood flow was significantly greater for the control group compared to the stroke group (p = 0.004). We found that despite the lower magnitude of muscle perfusion through the femoral artery in the stroke group, blood flow has a greater impact on peripheral fatigue for the control group; however, we observed a significant correlation between change in blood flow and motor unit firing rate modulation (r2 = 0.654, p = 0.004) during fatigue in the stroke group and not the control group (r2 = 0.024, p < 0.768). Taken together, this data showed a disruption between motor unit firing rates and post-contraction blood flow in the stroke group, suggesting that there may be a disruption to common inputs to both the reticular system and the corticospinal tract. This study provides novel insights in the relationship between the hyperemic response to exercise and motor unit firing behavior for poststroke force production and may provide new approaches for recovery by improving both blood flow and musc
AU  - Murphy,S
AU  - Durand,M
AU  - Negro,F
AU  - Farina,D
AU  - Hunter,S
AU  - Schmit,B
AU  - Gutterman,D
AU  - Hyngstrom,A
DO  - 10.3389/fphys.2019.00545
PY  - 2019///
TI  - The relationship between blood flow and motor unit firing rates in response to fatiguing exercise post-stroke
T2  - Frontiers in Physiology
UR  - http://dx.doi.org/10.3389/fphys.2019.00545
VL  - 10
ER  -
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