| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Autonomic and Cardiovascular Control Laboratory, Muscle Biology Laboratory, Department of Exercise Science, The University of Georgia, Athens, Georgia 30602
Dynamic one-legged knee extension (DKE) is
commonly used to examine physiological responses to "aerobic"
exercise. Muscle blood flow during DKE is often expressed relative to
quadriceps femoris muscle mass irrespective of work rate.
This is contrary to the notion that increased force is achieved by
recruitment in large muscles. The purpose of this study, therefore, was
to determine muscle use during DKE. Six subjects had magnetic resonance images taken of their quadriceps femoris before and after 4 min of DKE
at 20 and 40 W. Muscle use was determined by shifts in T2. The
cross-sectional area of quadriceps femoris that had an elevated T2 was
16 ± 1% (mean ± SE) preexercise, and 54 ± 5 and 94 ± 4% after 20- and 40-W DKE, respectively. Volume of quadriceps femoris
increased 11.4 ± 0.2% (P = 0.006), from 2,230 ± 233 cm3
before exercise to 2,473 ± 232 cm3 after 40-W DKE. Extrapolation
of these data indicates that 1,301 ± 111 cm3 of quadriceps femoris were
engaged during 20-W DKE compared with 2,292 ± 154 cm3 during 40-W DKE. By using
muscle blood flow data for submaximal DKE at 20 W [P. Andersen
and B. Saltin. J. Physiol. (Lond.)
366: 233-249, 1985; and L. B. Rowell, B. Saltin, B. Kiens, and N. J. Christensen. Am. J. Physiol. 251 (Heart Circ.
Physiol. 20): H1038-H1044, 1986] and
estimating muscle use in those studies from our data (total muscle mass × 0.54), extrapolated blood flow to active muscle (263 and 278 ml · min
1 · 100 g1, respectively) is
comparable to that obtained during peak aerobic DKE when expressed
relative to total muscle mass (243 and 250 ml · min1 · 100 g1,
respectively). These findings indicate that increased
power during aerobic DKE is achieved by recruitment.
Additionally, they suggest that blood flow to the active quadriceps
femoris muscle does not increase with increases in submaximal work rate
but instead is maximal to support aerobic metabolism. Thus increases in
muscle blood flow are directed to newly recruited muscle, not to
increased perfusion of muscle already engaged.
dynamic exercise; muscle blood flow; muscle recruitment
This article has been cited by other articles:
|
|
 |
|
  Y. Li, R. K. Dash, J. Kim, G. M. Saidel, and M. E. Cabrera Role of NADH/NAD+ transport activity and glycogen store on skeletal muscle energy metabolism during exercise: in silico studies Am J Physiol Cell Physiol, January 1, 2009; 296(1): C25 - C46. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. A. Parker, S. L. Smithmyer, J. A. Pelberg, A. D. Mishkin, and D. N. Proctor Sex-specific influence of aging on exercising leg blood flow J Appl Physiol, March 1, 2008; 104(3): 655 - 664. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Heinonen, S. V. Nesterov, J. Kemppainen, P. Nuutila, J. Knuuti, R. Laitio, M. Kjaer, R. Boushel, and K. K. Kalliokoski Role of adenosine in regulating the heterogeneity of skeletal muscle blood flow during exercise in humans J Appl Physiol, December 1, 2007; 103(6): 2042 - 2048. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Y. Endo, M. Kobayakawa, R. Kinugasa, S. Kuno, H. Akima, H. B. Rossiter, A. Miura, and Y. Fukuba Thigh muscle activation distribution and pulmonary VO2 kinetics during moderate, heavy, and very heavy intensity cycling exercise in humans Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2007; 293(2): R812 - R820. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Hannukainen, P. Nuutila, J. Kaprio, O. J Heinonen, U. M. Kujala, T. Janatuinen, T. Ronnemaa, J. Kapanen, M. Haaparanta-Solin, T. Viljanen, et al. Relationship between local perfusion and FFA uptake in human skeletal muscle--no effect of increased physical activity and aerobic fitness J Appl Physiol, November 1, 2006; 101(5): 1303 - 1311. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Ferguson, P. Krustrup, M. Kjaer, M. Mohr, D. Ball, and J. Bangsbo Effect of temperature on skeletal muscle energy turnover during dynamic knee-extensor exercise in humans J Appl Physiol, July 1, 2006; 101(1): 47 - 52. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Gonzalez-Alonso, S. P. Mortensen, E. A. Dawson, N. H. Secher, and R. Damsgaard Erythrocytes and the regulation of human skeletal muscle blood flow and oxygen delivery: role of erythrocyte count and oxygenation state of haemoglobin J. Physiol., April 1, 2006; 572(1): 295 - 305. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. J. Donato, A. Uberoi, D. W. Wray, S. Nishiyama, L. Lawrenson, and R. S. Richardson Differential effects of aging on limb blood flow in humans Am J Physiol Heart Circ Physiol, January 1, 2006; 290(1): H272 - H278. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. A. L. Calbet, M. Jensen-Urstad, G. van Hall, H.-C. Holmberg, H. Rosdahl, and B. Saltin Maximal muscular vascular conductances during whole body upright exercise in humans J. Physiol., July 1, 2004; 558(1): 319 - 331. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. S. Laaksonen, K. K. Kalliokoski, H. Kyrolainen, J. Kemppainen, M. Teras, H. Sipila, P. Nuutila, and J. Knuuti Skeletal muscle blood flow and flow heterogeneity during dynamic and isometric exercise in humans Am J Physiol Heart Circ Physiol, March 1, 2003; 284(3): H979 - H986. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Boushel, H. Langberg, J. Olesen, M. Nowak, L. Simonsen, J. Bulow, and M. Kjar Regional blood flow during exercise in humans measured by near-infrared spectroscopy and indocyanine green J Appl Physiol, November 1, 2000; 89(5): 1868 - 1878. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Gonzalez-Alonso, B. Quistorff, P. Krustrup, J. Bangsbo, and B. Saltin Heat production in human skeletal muscle at the onset of intense dynamic exercise J. Physiol., April 15, 2000; 524(2): 603 - 615. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. W G E Van Teeffelen and S. S Segal Effect of motor unit recruitment on functional vasodilatation in hamster retractor muscle J. Physiol., April 1, 2000; 524(1): 267 - 278. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Juel, H. Pilegaard, J. J. Nielsen, and J. Bangsbo Interstitial K+ in human skeletal muscle during and after dynamic graded exercise determined by microdialysis Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2000; 278(2): R400 - R406. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Radegran, E. Blomstrand, and B. Saltin Peak muscle perfusion and oxygen uptake in humans: importance of precise estimates of muscle mass J Appl Physiol, December 1, 1999; 87(6): 2375 - 2380. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
