Neuromechanical properties of the triceps surae in young and older adults

Barber, Lee A., Barrett, Rod S., Gillett, Jarred G., Cresswell, Andrew G. and Lichtwark, Glen A. (2013) Neuromechanical properties of the triceps surae in young and older adults. Experimental Gerontology, 48 11: 1147-1155. doi:10.1016/j.exger.2013.07.007

Author Barber, Lee A.
Barrett, Rod S.
Gillett, Jarred G.
Cresswell, Andrew G.
Lichtwark, Glen A.
Title Neuromechanical properties of the triceps surae in young and older adults
Journal name Experimental Gerontology   Check publisher's open access policy
ISSN 0531-5565
Publication date 2013-07-22
Sub-type Article (original research)
DOI 10.1016/j.exger.2013.07.007
Volume 48
Issue 11
Start page 1147
End page 1155
Total pages 9
Place of publication Philadelphia, PA, United States
Publisher Elsevier
Language eng
Abstract The aim of this study was to compare voluntary and involuntary force generating capacity of the triceps surae muscles in healthy young and older adult participants during isometric and isokinetic contractions. Ultrasound was used to measure medial gastrocnemius (MG) fascicle length during maximal voluntary isometric contractions and supra-maximal isometric twitch contractions at five ankle angles throughout the available range of motion, as well as isokinetic concentric and eccentric contractions at four ankle velocities. Maximum voluntary activation of the plantar flexors was assessed using the twitch interpolation technique. Peak plantar flexor torque was significantly lower in older adults compared to young participants by 42%, 28% and 43% during maximal voluntary isometric contractions, supra-maximal isometric twitch and concentric contractions respectively. No age-related differences in eccentric torque production were detected. When age-related differences in triceps surae muscle volume determined from MRI were taken into account, the age-related peak plantar flexor torque deficits for maximum voluntary isometric, supra-maximal twitch, and concentric contractions were 24%, 19% and 24% respectively. These age-related differences in torque were not explained by torque-length-velocity behaviour of the MG muscle fascicles, passive plantar flexor torque-angle properties, decreased neural drive of the plantar flexor muscles or antagonistic co-activation of the tibialis anterior muscle. The residual deficit in isometric and concentric plantar flexor torques in healthy older adults may involve reduced muscle quality. A significant reduction in supra-maximal twitch torque at longer MG fascicle lengths as well as a lower MG fascicle velocity during eccentric contractions in older adults was detected, which could possibly be a function of the reported increased Achilles tendon compliance in older adults.
Keyword Electrical stimulation
Muscle fascicle
Muscle volume
Voluntary activation
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Available online: 22 July 2013.

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Human Movement and Nutrition Sciences Publications
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Created: Tue, 13 Aug 2013, 00:18:30 EST by Deborah Noon on behalf of School of Human Movement and Nutrition Sciences