Document Detail


Exercise-induced muscle injury augments forearm vascular resistance during leg exercise.
MedLine Citation:
PMID:  9683431     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The purpose of the present investigation was to examine the effect of exercise-induced muscle injury on hemodynamic responses during exercise. Ten subjects performed unilateral isometric knee extensions (IKE) at 30% of preinjury maximum voluntary contraction to fatigue and for 3 min before and 48 h after muscle injury. Muscle injury was elicited by performing 8 sets of 10 repetitions of eccentric muscle actions of the knee extensor muscles (i.e., quadriceps muscles) by lowering a weight equivalent to 75% of eccentric maximum load. Exercise time to fatigue for IKE at 30% of maximum voluntary contraction in the injured leg was significantly decreased from preinjury to postinjury IKE (257 +/- 21 to 203 +/- 23 s; n = 10), but was unchanged in the control leg (244 +/- 16 to 254 +/- 20 s; n = 7). With the use of a 10-cm visual analog scale, ratings of muscle soreness in the injured leg increased from 0 to 5. 1 +/- 0.7 cm (P < 0.001) but were not changed in the control leg (0 both times). Both heart rate and mean arterial pressure responses to exercise were unchanged following muscle injury. Forearm blood flow and forearm vascular resistance were not different at rest and during the first minute of exercise before and after muscle injury. However, after muscle injury, forearm blood flow was significantly lower and forearm vascular resistance was significantly higher (P < 0.03) during the second and third minutes of exercise. There were no significant changes in any variables with the contralateral control leg. In four subjects, resting magnetic resonance images demonstrated a 23% greater relative cross-sectional area of the knee extensor muscles with an elevated transverse relaxation time in the injured versus control leg. The results indicate that forearm vascular resistance is augmented during isometric knee extension following muscle injury of the knee extensor muscles. The data suggest that muscle injury alters vascular control to non-exercising skeletal muscle during exercise.
Authors:
C A Ray; E T Mahoney; K M Hume
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  275     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1998 Aug 
Date Detail:
Created Date:  1998-09-16     Completed Date:  1998-09-16     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H443-7     Citation Subset:  IM; S    
Affiliation:
Autonomic and Cardiovascular Control Laboratory, Department of Exercise Science, University of Georgia, Athens, Georgia 30602, USA.
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MeSH Terms
Descriptor/Qualifier:
Adult
Athletic Injuries / physiopathology*
Blood Pressure
Exercise / physiology*
Forearm / blood supply*
Heart Rate
Humans
Isometric Contraction
Knee Joint
Leg / blood supply*
Male
Muscle, Skeletal / blood supply*,  injuries*
Pain
Regional Blood Flow
Vascular Resistance / physiology*
Weight-Bearing
Grant Support
ID/Acronym/Agency:
AR-44571/AR/NIAMS NIH HHS

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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