Motor Systems | Integrative Physiology | Muscle & Connective Tissue
Motor unit activity at recruitment when young and old adults support compliant loads
Michael A Pascoe*, Jeffrey R Gould, Roger M Enoka
*Corresponding author: Michael A Pascoe
Department of Physical Medicine & Rehabilitation, University of Colorado, Aurora, CO, USA
F1000Posters 2011, 2: 643 (poster) [ENGLISH]
Poster [6.33 MB]
58th American College of Sports Medicine Annual Meeting 2011, 31 May - 4 Jun 2011, 2295
Two variables are known to influence the discharge characteristics of human motor units; the age of the individual and the compliance of the load supported by the limb. The purpose of this study was to compare the influence of load compliance on the discharge characteristics of biceps brachii motor unit at recruitment in young and old adults. Twenty motor units were recorded for each group of subjects.
Young adults had a greater number of motor units that discharged action potentials intermittently at recruitment. Discharge rate was similar for the two sustained contractions in old, but was less in young for the lower target force. Additionally, discharge rate and discharge variability were similar across contraction time between the two sustained contractions in old adults and were different between contractions for young.
The data suggests that the integration of synaptic input differs between young and old adults.
No relevant conflicts of interest declared.
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