| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Exercise Science, University of Iowa, Iowa City, Iowa 52242
We sought to clarify the roles of contraction
frequency (speed) and contraction force (grade) in the rise in muscle
blood flow at the onset of locomotion. Shoemaker et al. (Can
J Physiol Pharmacol 76: 418-427, 1998) explored this
relationship in human handgrip exercise and found that the time course
of the rise in muscle vascular conductance was similar when a light
weight was lifted in a fast cadence and a heavy weight was lifted in a
slow cadence (total work constant). This indicates that muscle pumping (contraction frequency) was of limited importance in governing the time
course. Rather, vasodilator substances released in proportion to the
total work performed appeared to determine the pattern and extent of
the rise in conductance. We hypothesized that conductance would rise
faster during locomotion at a high speed (frequency) and low grade
(force) than at a low speed and high grade, despite similar total
increases in conductance, owing to more effective muscle pumping at
faster contraction rates. Seven male rats performed nine 1-min bouts of
treadmill locomotion across a combination of three speeds (5, 10, and
20 m/min) and three grades (
10, 0, and +15°) in random order.
Locomotion at 10 m/min and 0° grade and 20 m/min and 10° grade
led to an equal rise in terminal aortic vascular conductance. However,
the equal rise was achieved more quickly at the higher running speed,
suggestive of more effective muscle pumping. Across the nine
combinations of exercise, speed began to exert a statistically
significant influence on conductance by the 3rd s of locomotion. Grade
did not begin to exert an influence until the 12th s of locomotion
(similar to the delays reported for arteriolar dilation to muscle
contraction). Additional experiments in dogs provided similar results.
Thus the muscle pump appears to initiate the increase in blood flow in
proportion to contraction frequency at locomotion onset.
dog; rat; nitric oxide; muscle blood flow; iliac artery; terminal aorta; arterial pressure; vasodilation; vascular conductance
This article has been cited by other articles:
|
|
 |
|
  B. J. Wong and D. D. Sheriff Myogenic origin of the hypotension induced by rapid changes in posture in awake dogs following autonomic blockade J Appl Physiol, December 1, 2008; 105(6): 1837 - 1844. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. F. Ferreira, S. Koga, and T. J. Barstow Dynamics of noninvasively estimated microvascular O2 extraction during ramp exercise J Appl Physiol, December 1, 2007; 103(6): 1999 - 2004. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Koga, D. C. Poole, L. F. Ferreira, B. J. Whipp, N. Kondo, T. Saitoh, E. Ohmae, and T. J. Barstow Spatial heterogeneity of quadriceps muscle deoxygenation kinetics during cycle exercise J Appl Physiol, December 1, 2007; 103(6): 2049 - 2056. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. L. Walker, N. R. Saunders, D. Jensen, J. L. Kuk, S.-L. Wong, K. E. Pyke, E. M. Dwyer, and M. E. Tschakovsky Do vasoregulatory mechanisms in exercising human muscle compensate for changes in arterial perfusion pressure? Am J Physiol Heart Circ Physiol, November 1, 2007; 293(5): H2928 - H2936. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. F Ferreira, A. J Harper, D. K Townsend, B. J Lutjemeier, and T. J Barstow Kinetics of estimated human muscle capillary blood flow during recovery from exercise Exp Physiol, September 1, 2005; 90(5): 715 - 726. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Sheriff, P. S. Clifford, J. J. Hamann, Z. Valic, and J. B. Buckwalter Point: The muscle pump raises muscle blood flow during locomotion J Appl Physiol, July 1, 2005; 99(1): 371 - 375. [Full Text] [PDF]
|
|
|
|
|
|
L. F. Ferreira, D. K. Townsend, B. J. Lutjemeier, and T. J. Barstow Muscle capillary blood flow kinetics estimated from pulmonary O2 uptake and near-infrared spectroscopy J Appl Physiol, May 1, 2005; 98(5): 1820 - 1828. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. J. Lutjemeier, A. Miura, B. W. Scheuermann, S. Koga, D. K. Townsend, and T. J. Barstow Muscle contraction-blood flow interactions during upright knee extension exercise in humans J Appl Physiol, April 1, 2005; 98(4): 1575 - 1583. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. R. Saunders, F. A. Dinenno, K. E. Pyke, A. M. Rogers, and M. E. Tschakovsky Impact of combined NO and PG blockade on rapid vasodilation in a forearm mild-to-moderate exercise transition in humans Am J Physiol Heart Circ Physiol, January 1, 2005; 288(1): H214 - H220. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. R. Saunders and M. E. Tschakovsky Evidence for a rapid vasodilatory contribution to immediate hyperemia in rest-to-mild and mild-to-moderate forearm exercise transitions in humans J Appl Physiol, September 1, 2004; 97(3): 1143 - 1151. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. E. Tschakovsky and D. D. Sheriff Immediate exercise hyperemia: contributions of the muscle pump vs. rapid vasodilation J Appl Physiol, August 1, 2004; 97(2): 739 - 747. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Rogers and D. D. Sheriff Role of estrogen in nitric oxide- and prostaglandin-dependent modulation of vascular conductance during treadmill locomotion in rats J Appl Physiol, August 1, 2004; 97(2): 756 - 763. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. N. Stark-Leyva, K. C. Beck, and B. D. Johnson Influence of expiratory loading and hyperinflation on cardiac output during exercise J Appl Physiol, May 1, 2004; 96(5): 1920 - 1927. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. E. Tschakovsky, A. M. Rogers, K. E. Pyke, N. R. Saunders, N. Glenn, S. J. Lee, T. Weissgerber, and E. M. Dwyer Immediate exercise hyperemia in humans is contraction intensity dependent: evidence for rapid vasodilation J Appl Physiol, February 1, 2004; 96(2): 639 - 644. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. D. Sheriff Muscle pump function during locomotion: mechanical coupling of stride frequency and muscle blood flow Am J Physiol Heart Circ Physiol, June 1, 2003; 284(6): H2185 - H2191. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. D. Sheriff and T. M. Zidon Delay of muscle vasodilation to changes in work rate (treadmill grade) during locomotion J Appl Physiol, May 1, 2003; 94(5): 1903 - 1909. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E.R. Diederich, B.J. Behnke, P. McDonough, C.A. Kindig, T.J. Barstow, D.C. Poole, and T.I. Musch Dynamics of microvascular oxygen partial pressure in contracting skeletal muscle of rats with chronic heart failure Cardiovasc Res, December 1, 2002; 56(3): 479 - 486. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
