Linked Life Data

11090570

Source:http://linkedlifedata.com/resource/pubmed/id/11090570

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2000-12-26
pubmed:abstractText
We hypothesized that decrements in maximum power output (W(max)) of the rat diaphragm (Dia) muscle with repetitive activation are due to a disproportionate reduction in force (force fatigue) compared with a slowing of shortening velocity (velocity fatigue). Segments of midcostal Dia muscle were mounted in vitro (26 degrees C) and stimulated directly at 75 Hz in 400-ms-duration trains repeated each second (duty cycle = 0.4) for 120 s. A novel technique was used to monitor instantaneous reductions in maximum specific force (P(o)) and W(max) during fatigue. During each stimulus train, activation was isometric for the initial 360 ms during which P(o) was measured; the muscle was then allowed to shorten at a constant velocity (30% V(max)) for the final 40 ms, and W(max) was determined. Compared with initial values, after 120 s of repetitive activation, P(o) and W(max) decreased by 75 and 73%, respectively. Maximum shortening velocity was measured in two ways: by extrapolation of the force-velocity relationship (V(max)) and using the slack test [maximum unloaded shortening velocity (V(o))]. After 120 s of repetitive activation, V(max) slowed by 44%, whereas V(o) slowed by 22%. Thus the decrease in W(max) with repetitive activation was dominated by force fatigue, with velocity fatigue playing a secondary role. On the basis of a greater slowing of V(max) vs. V(o), we also conclude that force and power fatigue cannot be attributed simply to the total inactivation of the most fatigable fiber types.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
8750-7587
pubmed:author
pubmed:issnType
Print
pubmed:volume
89
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2215-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Power fatigue of the rat diaphragm muscle.
pubmed:affiliation
Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't