| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Physiology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City 37614.
1. Changes in blood pressure and heart rate were measured in six healthy male subjects during voluntary isometric contractions of the forearm and quadriceps muscles. Arterial pressure was measured directly via a catheter inserted into the radial artery of the non-contracting arm. Each subject exerted two types of contractions: (a) sustained contractions at 70% of the maximum voluntary contraction (MVC) until fatigue occurred and (b) sustained contractions starting at maximum tension (100% MVC), held for a total duration of 1 min. 2. During fatiguing contractions at 70% MVC, there was a progressive increase in blood pressure, reaching a peak level at fatigue. The same level of mean arterial pressure was achieved during contractions of the same relative tension, regardless of the muscle mass. The same trend was observed for the changes in heart rate. 3. During contractions which started with the maximum tension, where tension fell continuously during the 60 s of maximal effort, mean arterial pressure rapidly increased to high levels within a few seconds, and then increased further by 20-30 mmHg during the sustained maximal effort. There was no difference in the initial rapid increases in mean arterial pressure, nor in the final mean arterial pressures reached between contractions of the forearm or quadriceps muscles. There were no differences in the heart rates achieved during these contractions either. 4. There was no significant difference between the mean arterial pressures observed at fatigue of a 70% MVC contraction or at the end of the 60 s maximum effort during handgrip contractions, or during contractions with the quadriceps muscles. 5. These results support the view that muscle mass is not a determinant of the magnitude of the cardiovascular reflexes during fatiguing isometric contractions in man.
This article has been cited by other articles:
|
|
 |
|
  J. M. Stewart, I. Taneja, and M. S. Medow Reduced central blood volume and cardiac output and increased vascular resistance during static handgrip exercise in postural tachycardia syndrome Am J Physiol Heart Circ Physiol, September 1, 2007; 293(3): H1908 - H1917. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Momen, B. Handly, A. Kunselman, U. A. Leuenberger, and L. I. Sinoway Influence of sex and active muscle mass on renal vascular responses during static exercise Am J Physiol Heart Circ Physiol, July 1, 2006; 291(1): H121 - H126. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. K. Bergersen, T. W. Hartgill, and J. Pirhonen Cerebrovascular response to normal pregnancy: a longitudinal study Am J Physiol Heart Circ Physiol, May 1, 2006; 290(5): H1856 - H1861. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. P Fisher and M. J White Muscle afferent contributions to the cardiovascular response to isometric exercise Exp Physiol, November 1, 2004; 89(6): 639 - 646. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. K. Hunter and R. M. Enoka Sex differences in the fatigability of arm muscles depends on absolute force during isometric contractions J Appl Physiol, December 1, 2001; 91(6): 2686 - 2694. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Galvez, J. P. Alonso, L. A. Sangrador, and G. Navarro Effect of muscle mass and intensity of isometric contraction on heart rate J Appl Physiol, February 1, 2000; 88(2): 487 - 492. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Iellamo, M. Massaro, G. Raimondi, G. Peruzzi, and J. M. Legramante Role of muscular factors in cardiorespiratory responses to static exercise: contribution of reflex mechanisms J Appl Physiol, January 1, 1999; 86(1): 174 - 180. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
