Linked Life Data

20383774

Source:http://linkedlifedata.com/resource/pubmed/id/20383774

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2010-8-12
pubmed:abstractText
In the biceps brachii, age-related differences in synaptic excitability and muscle architecture may affect motor unit (MU) activity differently depending on the position of the forearm. It was hypothesised that as a result of these age-related differences, greater changes in MU activity would accompany a change in forearm position in old when compared with young men. Six young (22 +/- 3 years) and six old (84 +/- 3 years) men maintained isometric elbow flexion at 10% of maximal voluntary contraction (MVC) during changes in forearm position. Forty-nine MUs in the short (SBB) and long (LBB) heads of the biceps brachii were followed. Motor unit recruitment and de-recruitment thresholds, motor unit discharge rates (MUDRs), and MU discharge variability were measured. Although an age-related decrease in MU recruitment thresholds, and increase in MU discharge variability was evident, changes in forearm position influenced MUDRs similarly in young and old men (P = 0.27). Motor unit recruitment thresholds of the SBB were highest in the pronated position (8.2 +/- 2.9 %MVC), whereas in the LBB they were highest in the supinated position (8.6 +/- 2.0 %MVC). Motor unit discharge rates of the LBB did not change with forearm position. In the SBB, MUDRs were highest when the forearm was supinated, and also greater when compared with the LBB in this position. No position-dependent changes were observed for MU discharge variability in the LBB, but the SBB exhibited greatest MU discharge variability in the pronated position. The results suggest that MU activity is modulated following a change in forearm position, but the response is similar in young and old adults.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1439-6327
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
110
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
27-38
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Age independent and position-dependent alterations in motor unit activity of the biceps brachii.
pubmed:affiliation
School of Kinesiology, University of Western Ontario, London, ON, Canada.
pubmed:publicationType
Journal Article, Comparative Study