Cargando…

The influence of residual force enhancement on spinal and supraspinal excitability

BACKGROUND: Following active muscle lengthening, there is an increase in steady-state isometric force as compared with a purely isometric contraction at the same muscle length and level of activation. This fundamental property of skeletal muscle is known as residual force enhancement (RFE). While th...

Descripción completa

Detalles Bibliográficos
Autores principales: Sypkes, Caleb T., Kozlowski, Benjamin J., Grant, Jordan, Bent, Leah R., McNeil, Chris J., Power, Geoffrey A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: PeerJ Inc. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6078065/
https://www.ncbi.nlm.nih.gov/pubmed/30083481
http://dx.doi.org/10.7717/peerj.5421
_version_ 1783345028775542784
author Sypkes, Caleb T.
Kozlowski, Benjamin J.
Grant, Jordan
Bent, Leah R.
McNeil, Chris J.
Power, Geoffrey A.
author_facet Sypkes, Caleb T.
Kozlowski, Benjamin J.
Grant, Jordan
Bent, Leah R.
McNeil, Chris J.
Power, Geoffrey A.
author_sort Sypkes, Caleb T.
collection PubMed
description BACKGROUND: Following active muscle lengthening, there is an increase in steady-state isometric force as compared with a purely isometric contraction at the same muscle length and level of activation. This fundamental property of skeletal muscle is known as residual force enhancement (RFE). While the basic mechanisms contributing to this increase in steady-state isometric force have been well documented, changes in central nervous system (CNS) excitability for submaximal contractions during RFE are unclear. The purpose of this study was to investigate spinal and supraspinal excitability in the RFE isometric steady-state following active lengthening of the ankle dorsiflexor muscles. METHODS: A total of 11 male participants (20–28 years) performed dorsiflexions at a constant level of electromyographic activity (40% of maximum). Half of the contractions were purely isometric (8 s at an ankle angle of 130°), and the other half were during the RFE isometric steady-state following active lengthening (2 s isometric at 90°, a 1 s lengthening phase at 40°/s, and 5 s at 130°). Motor evoked potentials (MEPs), cervicomedullary motor evoked potentials (CMEPs), and compound muscle action potentials (M-waves) were recorded from the tibialis anterior during the purely isometric contraction and RFE isometric steady-state. RESULTS: Compared to the purely isometric condition, following active lengthening, there was 10% RFE (p < 0.05), with a 17% decrease in normalized CMEP amplitude (CMEP/M(max)) (p < 0.05) and no change in normalized MEP amplitude (MEP/CMEP) (p > 0.05). DISCUSSION: These results indicate that spinal excitability is reduced during submaximal voluntary contractions in the RFE state with no change in supraspinal excitability. These findings may have further implications to everyday life offering insight into how the CNS optimizes control of skeletal muscle following submaximal active muscle lengthening.
format Online
Article
Text
id pubmed-6078065
institution National Center for Biotechnology Information
language English
publishDate 2018
publisher PeerJ Inc.
record_format MEDLINE/PubMed
spelling pubmed-60780652018-08-06 The influence of residual force enhancement on spinal and supraspinal excitability Sypkes, Caleb T. Kozlowski, Benjamin J. Grant, Jordan Bent, Leah R. McNeil, Chris J. Power, Geoffrey A. PeerJ Neuroscience BACKGROUND: Following active muscle lengthening, there is an increase in steady-state isometric force as compared with a purely isometric contraction at the same muscle length and level of activation. This fundamental property of skeletal muscle is known as residual force enhancement (RFE). While the basic mechanisms contributing to this increase in steady-state isometric force have been well documented, changes in central nervous system (CNS) excitability for submaximal contractions during RFE are unclear. The purpose of this study was to investigate spinal and supraspinal excitability in the RFE isometric steady-state following active lengthening of the ankle dorsiflexor muscles. METHODS: A total of 11 male participants (20–28 years) performed dorsiflexions at a constant level of electromyographic activity (40% of maximum). Half of the contractions were purely isometric (8 s at an ankle angle of 130°), and the other half were during the RFE isometric steady-state following active lengthening (2 s isometric at 90°, a 1 s lengthening phase at 40°/s, and 5 s at 130°). Motor evoked potentials (MEPs), cervicomedullary motor evoked potentials (CMEPs), and compound muscle action potentials (M-waves) were recorded from the tibialis anterior during the purely isometric contraction and RFE isometric steady-state. RESULTS: Compared to the purely isometric condition, following active lengthening, there was 10% RFE (p < 0.05), with a 17% decrease in normalized CMEP amplitude (CMEP/M(max)) (p < 0.05) and no change in normalized MEP amplitude (MEP/CMEP) (p > 0.05). DISCUSSION: These results indicate that spinal excitability is reduced during submaximal voluntary contractions in the RFE state with no change in supraspinal excitability. These findings may have further implications to everyday life offering insight into how the CNS optimizes control of skeletal muscle following submaximal active muscle lengthening. PeerJ Inc. 2018-08-03 /pmc/articles/PMC6078065/ /pubmed/30083481 http://dx.doi.org/10.7717/peerj.5421 Text en © 2018 Sypkes et al. http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited.
spellingShingle Neuroscience
Sypkes, Caleb T.
Kozlowski, Benjamin J.
Grant, Jordan
Bent, Leah R.
McNeil, Chris J.
Power, Geoffrey A.
The influence of residual force enhancement on spinal and supraspinal excitability
title The influence of residual force enhancement on spinal and supraspinal excitability
title_full The influence of residual force enhancement on spinal and supraspinal excitability
title_fullStr The influence of residual force enhancement on spinal and supraspinal excitability
title_full_unstemmed The influence of residual force enhancement on spinal and supraspinal excitability
title_short The influence of residual force enhancement on spinal and supraspinal excitability
title_sort influence of residual force enhancement on spinal and supraspinal excitability
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6078065/
https://www.ncbi.nlm.nih.gov/pubmed/30083481
http://dx.doi.org/10.7717/peerj.5421
work_keys_str_mv AT sypkescalebt theinfluenceofresidualforceenhancementonspinalandsupraspinalexcitability
AT kozlowskibenjaminj theinfluenceofresidualforceenhancementonspinalandsupraspinalexcitability
AT grantjordan theinfluenceofresidualforceenhancementonspinalandsupraspinalexcitability
AT bentleahr theinfluenceofresidualforceenhancementonspinalandsupraspinalexcitability
AT mcneilchrisj theinfluenceofresidualforceenhancementonspinalandsupraspinalexcitability
AT powergeoffreya theinfluenceofresidualforceenhancementonspinalandsupraspinalexcitability
AT sypkescalebt influenceofresidualforceenhancementonspinalandsupraspinalexcitability
AT kozlowskibenjaminj influenceofresidualforceenhancementonspinalandsupraspinalexcitability
AT grantjordan influenceofresidualforceenhancementonspinalandsupraspinalexcitability
AT bentleahr influenceofresidualforceenhancementonspinalandsupraspinalexcitability
AT mcneilchrisj influenceofresidualforceenhancementonspinalandsupraspinalexcitability
AT powergeoffreya influenceofresidualforceenhancementonspinalandsupraspinalexcitability