Impaired Voluntary Neuromuscular Activation Limits Muscle Power in Mobility-Limited Older Adults
Open Access
- 15 February 2010
- journal article
- research article
- Published by Oxford University Press (OUP) in The Journals of Gerontology: Series A
- Vol. 65A (5), 495-502
- https://doi.org/10.1093/gerona/glq012
Abstract
Age-related alterations of neuromuscular activation may contribute to deficits in muscle power and mobility function. This study assesses whether impaired activation of the agonist quadriceps and antagonist hamstrings, including amplitude- and velocity-dependent characteristics of activation, may explain differences in leg extension torque and power between healthy middle-aged, healthy older, and mobility-limited older adults. Torque, power, and electromyography were recorded during maximal voluntary leg extension trials across a range of velocities on an isokinetic dynamometer. Neuromuscular activation was similar between middle-aged and older healthy groups, with differences in torque and power explained predominantly by muscle size. However, the older mobility–limited group demonstrated marked impairment of torque, power, and agonist muscle activation, with the greatest deficits occurring at the fastest movement velocities. Agonist muscle activation was found to be strongly associated with torque output. Similar neuromuscular activation between the middle-aged and older healthy groups indicates that impaired voluntary activation is not an obligatory consequence of aging. However, the finding that the mobility-limited group exhibited impaired activation of the agonist quadriceps and concomitant deficits in torque and power output suggests that neuromuscular activation deficits may contribute to compromised mobility function in older adults.Keywords
This publication has 39 references indexed in Scilit:
- Muscle fiber size and function in elderly humans: a longitudinal studyJournal of Applied Physiology, 2008
- Activation impairment alters muscle torque–velocity in the knee extensors of persons with post-stroke hemiparesisClinical Neurophysiology, 2006
- Doublet Discharges in Motoneurons of Young and Older AdultsJournal of Neurophysiology, 2006
- Aging does not affect voluntary activation of the ankle dorsiflexors during isometric, concentric, and eccentric contractionsJournal of Applied Physiology, 2005
- The influence of ageing on the force–velocity–power characteristics of human elbow flexor musclesExperimental Gerontology, 2003
- Are voluntary muscle activation deficits in older adults meaningful?Muscle & Nerve, 2002
- Contractile muscle volume and agonist‐antagonist coactivation account for differences in torque between young and older womenMuscle & Nerve, 2002
- The Relationship Between Leg Power and Physical Performance in Mobility‐Limited Older PeopleJournal of the American Geriatrics Society, 2002
- Maximal strength and power characteristics in isometric and dynamic actions of the upper and lower extremities in middle‐aged and older menActa Physiologica Scandinavica, 1999
- Strength, Power and Related Functional Ability of Healthy People Aged 65–89 YearsAge and Ageing, 1994