Corticospinal responses during passive shortening and lengthening of tibialis anterior and soleus in older compared to younger adults

Škarabot, Jakob, Ansdell, Paul, Howatson, Glyn, Goodall, Stuart and Durbaba, Rade (2019) Corticospinal responses during passive shortening and lengthening of tibialis anterior and soleus in older compared to younger adults. Experimental Physiology. ISSN 0958-0670 (In Press)

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Official URL: https://doi.org/10.1113/ep088204

Abstract

Corticospinal responses have been shown to increase and decrease with passive muscle shortening and lengthening, respectively, as a result of changes in muscle spindle afferent feedback. The aging sensory system is accompanied by a number of alterations that might influence the processing and integration of sensory information. Consequently, corticospinal excitability might be differently modulated whilst changing muscle length. In 10 older adults (66 ± 4 years), corticospinal responses (MEP/Mmax) were evoked during a static position, passive shortening, and lengthening of soleus (SOL) and tibialis anterior (TA), and these data were compared to the re‐analysed data pool of 18 younger adults (25 ± 4 years; Škarabot et al. 2019, Exp Brain Res 237:2239‐2254). Resting motor threshold was greater in SOL compared to TA (p < 0.001), but did not differ between young and older (p = 0.405). No differences were observed in MEP/Mmax between the static position, passive shortening or lengthening in SOL (young: all 0.02 ± 0.01; older: 0.05 ± 0.04, 0.03 ± 0.02 and 0.04 ± 0.01, respectively; p = 0.298), and responses were not dependent on age (p = 0.090). Conversely, corticospinal responses in TA were differently modulated between the age groups (p = 0.002), with greater MEP/Mmax during passive shortening (0.22 ± 0.12) compared to passive lengthening (0.13 ± 0.10) and static position (0.10 ± 0.05) in young (p < 0.001), but unchanged in older adults (0.19 ± 0.11, 0.22 ± 0.11 and 0.18 ± 0.07, respectively; p≥0.867). The present experiment shows that length‐dependent changes in corticospinal excitability in TA of the young are not evident in older adults. This suggests impaired sensorimotor response during muscle length changes in older age that might only be present in ankle flexors, but not extensors.

Item Type: Article
Uncontrolled Keywords: afferent, motor evoked potential, muscle spindle
Subjects: C600 Sports Science
C800 Psychology
Department: Faculties > Health and Life Sciences > Applied Sciences
Faculties > Health and Life Sciences > Social Work, Education and Community Wellbeing
Depositing User: Elena Carlaw
Date Deposited: 07 Jan 2020 15:39
Last Modified: 07 Jan 2020 15:45
URI: http://nrl.northumbria.ac.uk/id/eprint/41844

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