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Motor Variability during Sustained Contractions Increases with Cognitive Demand in Older Adults

To expose cortical involvement in age-related changes in motor performance, we compared steadiness (force fluctuations) and fatigability of submaximal isometric contractions with the ankle dorsiflexor muscles in older and young adults and with varying levels of cognitive demand imposed. Sixteen youn...

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Autores principales: Vanden Noven, Marnie L., Pereira, Hugo M., Yoon, Tejin, Stevens, Alyssa A., Nielson, Kristy A., Hunter, Sandra K.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4033244/
https://www.ncbi.nlm.nih.gov/pubmed/24904410
http://dx.doi.org/10.3389/fnagi.2014.00097
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author Vanden Noven, Marnie L.
Pereira, Hugo M.
Yoon, Tejin
Stevens, Alyssa A.
Nielson, Kristy A.
Hunter, Sandra K.
author_facet Vanden Noven, Marnie L.
Pereira, Hugo M.
Yoon, Tejin
Stevens, Alyssa A.
Nielson, Kristy A.
Hunter, Sandra K.
author_sort Vanden Noven, Marnie L.
collection PubMed
description To expose cortical involvement in age-related changes in motor performance, we compared steadiness (force fluctuations) and fatigability of submaximal isometric contractions with the ankle dorsiflexor muscles in older and young adults and with varying levels of cognitive demand imposed. Sixteen young (20.4 ± 2.1 year: 8 men, 9 women) and 17 older adults (68.8 ± 4.4 years: 9 men, 8 women) attended three sessions and performed a 40 s isometric contraction at 5% maximal voluntary contraction (MVC) force followed by an isometric contraction at 30% MVC until task failure. The cognitive demand required during the submaximal contractions in each session differed as follows: (1) high-cognitive demand session where difficult mental math was imposed (counting backward by 13 from a 4-digit number); (2) low-cognitive demand session which involved simple mental math (counting backward by 1); and (3) control session with no mental math. Anxiety was elevated during the high-cognitive demand session compared with other sessions for both age groups but more so for the older adults than young adults (p  < 0.05). Older adults had larger force fluctuations than young adults during: (1) the 5% MVC task as cognitive demand increased (p  = 0.007), and (2) the fatiguing contraction for all sessions (p  = 0.002). Time to task failure did not differ between sessions or age groups (p  > 0.05), but the variability between sessions (standard deviation of three sessions) was greater for older adults than young (2.02 ± 1.05 vs. 1.25 ± 0.51 min, p  < 0.05). Thus, variability in lower limb motor performance for low- and moderate-force isometric tasks increased with age and was exacerbated when cognitive demand was imposed, and may be related to modulation of synergist and antagonist muscles and an altered neural strategy with age originating from central sources. These data have significant implications for cognitively demanding low-force motor tasks that are relevant to functional and ergonomic in an aging workforce.
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spelling pubmed-40332442014-06-05 Motor Variability during Sustained Contractions Increases with Cognitive Demand in Older Adults Vanden Noven, Marnie L. Pereira, Hugo M. Yoon, Tejin Stevens, Alyssa A. Nielson, Kristy A. Hunter, Sandra K. Front Aging Neurosci Neuroscience To expose cortical involvement in age-related changes in motor performance, we compared steadiness (force fluctuations) and fatigability of submaximal isometric contractions with the ankle dorsiflexor muscles in older and young adults and with varying levels of cognitive demand imposed. Sixteen young (20.4 ± 2.1 year: 8 men, 9 women) and 17 older adults (68.8 ± 4.4 years: 9 men, 8 women) attended three sessions and performed a 40 s isometric contraction at 5% maximal voluntary contraction (MVC) force followed by an isometric contraction at 30% MVC until task failure. The cognitive demand required during the submaximal contractions in each session differed as follows: (1) high-cognitive demand session where difficult mental math was imposed (counting backward by 13 from a 4-digit number); (2) low-cognitive demand session which involved simple mental math (counting backward by 1); and (3) control session with no mental math. Anxiety was elevated during the high-cognitive demand session compared with other sessions for both age groups but more so for the older adults than young adults (p  < 0.05). Older adults had larger force fluctuations than young adults during: (1) the 5% MVC task as cognitive demand increased (p  = 0.007), and (2) the fatiguing contraction for all sessions (p  = 0.002). Time to task failure did not differ between sessions or age groups (p  > 0.05), but the variability between sessions (standard deviation of three sessions) was greater for older adults than young (2.02 ± 1.05 vs. 1.25 ± 0.51 min, p  < 0.05). Thus, variability in lower limb motor performance for low- and moderate-force isometric tasks increased with age and was exacerbated when cognitive demand was imposed, and may be related to modulation of synergist and antagonist muscles and an altered neural strategy with age originating from central sources. These data have significant implications for cognitively demanding low-force motor tasks that are relevant to functional and ergonomic in an aging workforce. Frontiers Media S.A. 2014-05-22 /pmc/articles/PMC4033244/ /pubmed/24904410 http://dx.doi.org/10.3389/fnagi.2014.00097 Text en Copyright © 2014 Vanden Noven, Pereira, Yoon, Stevens, Nielson and Hunter. http://creativecommons.org/licenses/by/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Neuroscience
Vanden Noven, Marnie L.
Pereira, Hugo M.
Yoon, Tejin
Stevens, Alyssa A.
Nielson, Kristy A.
Hunter, Sandra K.
Motor Variability during Sustained Contractions Increases with Cognitive Demand in Older Adults
title Motor Variability during Sustained Contractions Increases with Cognitive Demand in Older Adults
title_full Motor Variability during Sustained Contractions Increases with Cognitive Demand in Older Adults
title_fullStr Motor Variability during Sustained Contractions Increases with Cognitive Demand in Older Adults
title_full_unstemmed Motor Variability during Sustained Contractions Increases with Cognitive Demand in Older Adults
title_short Motor Variability during Sustained Contractions Increases with Cognitive Demand in Older Adults
title_sort motor variability during sustained contractions increases with cognitive demand in older adults
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4033244/
https://www.ncbi.nlm.nih.gov/pubmed/24904410
http://dx.doi.org/10.3389/fnagi.2014.00097
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