| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 The Copenhagen Muscle Research Centre, University of Copenhagen, and Rigshospitalet, DK-2100 Copenhagen Ø, Denmark; and 2 Department of Preventive Medicine and Public Health, Tokyo Medical University, Tokyo 160-8402, Japan
Whether limb blood flow is directly regulated to match the work rate, independent of the rate of contraction, remains elusive. This study therefore investigated the relationship between femoral arterial blood flow (FABF; Doppler ultrasound) and "external" (applied load) as well as "total" [external + "internal" (potential and kinetic energy changes of the moving lower leg)] work rate, during steady-state one-legged, dynamic, knee extensor exercise (1L-KEE) in the sitting position at different contraction rates. Ten subjects performed 1L-KEE at 30, 60, and 90 contractions/min (cpm) 1) at constant resistive loads of 0.2 and 0.5 kg inducing incremental external work rates (study I) and 2) at different relative resistive loads inducing constant external work rates of 9 and 18 W (study II). Moreover, 3) six subjects performed 1L-KEE at 60 and 100 cpm at incremental total work rates of 40, 50, 60, and 70 W (study III). In study I, FABF increased (P < 0.001) with increasing contraction frequency and external work rate, for each resistive load. In study II, FABF increased (P < 0.001) with increasing contraction frequency for each constant external work rate. Of major importance in study III, however, was that FABF, although increasing linearly with the total work rate, was not different (P = not significant) between contraction rates, at the total work rates of 40, 50, 60, and 70 W, respectively. Furthermore, FABF correlated linearly and positively with both the external and total work rate for each contraction frequency. In conclusion, the findings support the concept that leg blood flow during 1L-KEE in a normal knee extensor ergometer is matched directly in relation to the total work rate and metabolic activity, irrespective of the contraction frequency. The rate of contraction seems erroneously to influence the results only when it is related to the external work rate without taking into account the internal work component.
exercise hyperemia; human; knee extensor exercise; limb blood flow; Doppler ultrasound
This article has been cited by other articles:
|
|
 |
|
  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]
|
|
|
|
 |
|
 D. M. Keller, S. Ogoh, S. Greene, A Olivencia-Yurvati, and P. B Raven Inhibition of KATP channel activity augments baroreflex-mediated vasoconstriction in exercising human skeletal muscle J. Physiol., November 15, 2004; 561(1): 273 - 282. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. M. Keller, P. J Fadel, S. Ogoh, R. M. Brothers, M. Hawkins, A. Olivencia-Yurvati, and P. B Raven Carotid baroreflex control of leg vasculature in exercising and non-exercising skeletal muscle in humans J. Physiol., November 15, 2004; 561(1): 283 - 293. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. L. Olive, J. M. Slade, G. A. Dudley, and K. K. McCully Blood flow and muscle fatigue in SCI individuals during electrical stimulation J Appl Physiol, February 1, 2003; 94(2): 701 - 708. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Sjogaard, E. A. Hansen, and T. Osada Blood flow and oxygen uptake increase with total power during five different knee-extension contraction rates J Appl Physiol, November 1, 2002; 93(5): 1676 - 1684. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
