Dissociation between the time courses of femoral artery blood flow and pulmonary V̇O2during repeated bouts of heavy knee extension exercise in humans

2004 ◽  
Vol 89 (3) ◽  
pp. 243-253 ◽  
Author(s):  
Yoshiyuki Fukuba ◽  
Yukie Ohe ◽  
Akira Miura ◽  
Asami Kitano ◽  
Masako Endo ◽  
...  
Keyword(s):  
Blood Flow ◽  
Femoral Artery ◽  
Knee Extension ◽  
Artery Blood Flow ◽  
Femoral Artery Blood Flow ◽  
Time Courses ◽  
Knee Extension Exercise ◽  
Exercise In Humans

Kinetics of V̇o2 and femoral artery blood flow during heavy-intensity, knee-extension exercise

2005 ◽  
Vol 99 (2) ◽  
pp. 683-690 ◽  
Author(s):  
Nicole D. Paterson ◽  
John M. Kowalchuk ◽  
Donald H. Paterson
Keyword(s):  
Blood Flow ◽  
Femoral Artery ◽  
Time Course ◽  
Slow Component ◽  
Knee Extension ◽  
Artery Blood Flow ◽  
Phase 2 ◽  
Femoral Artery Blood Flow ◽  
Knee Extension Exercise ◽  
Kinetics Of

It has been suggested that, during heavy-intensity exercise, O2 delivery may limit oxygen uptake (V̇o2) kinetics; however, there are limited data regarding the relationship of blood flow and V̇o2 kinetics for heavy-intensity exercise. The purpose was to determine the exercise on-transient time course of femoral artery blood flow (Q̇leg) in relation to V̇o2 during heavy-intensity, single-leg, knee-extension exercise. Five young subjects performed five to eight repeats of heavy-intensity exercise with measures of breath-by-breath pulmonary V̇o2 and Doppler ultrasound femoral artery mean blood velocity and vessel diameter. The phase 2 time frame for V̇o2 and Q̇leg was isolated and fit with a monoexponent to characterize the amplitude and time course of the responses. Amplitude of the phase 3 response was also determined. The phase 2 time constant for V̇o2 of 29.0 s and time constant for Q̇leg of 24.5 s were not different. The change (Δ) in V̇o2 response to the end of phase 2 of 0.317 l/min was accompanied by a ΔQ̇leg of 2.35 l/min, giving a ΔQ̇leg-to-ΔV̇o2 ratio of 7.4. A slow-component V̇o2 of 0.098 l/min was accompanied by a further Q̇leg increase of 0.72 l/min (ΔQ̇leg-to-ΔV̇o2 ratio = 7.3). Thus the time course of Q̇leg was similar to that of muscle V̇o2 (as measured by the phase 2 V̇o2 kinetics), and throughout the on-transient the amplitude of the Q̇leg increase achieved (or exceeded) the Q̇leg-to-V̇o2 ratio steady-state relationship (ratio ∼4.9). Additionally, the V̇o2 slow component was accompanied by a relatively large rise in Q̇leg, with the increased O2 delivery meeting the increased V̇o2. Thus, in heavy-intensity, single-leg, knee-extension exercise, the amplitude and kinetics of blood flow to the exercising limb appear to be closely linked to the V̇o2 kinetics.

Ultrasound Doppler estimates of femoral artery blood flow during dynamic knee extensor exercise in humans

1997 ◽  
Vol 83 (4) ◽  
pp. 1383-1388 ◽  
Author(s):  
G. Rådegran
Keyword(s):  
Blood Flow ◽  
Femoral Artery ◽  
Coefficient Of Variation ◽  
Knee Extensor ◽  
Dynamic Exercise ◽  
Artery Blood Flow ◽  
Ultrasound Doppler ◽  
Femoral Artery Blood Flow ◽  
Human Limb ◽  
Exercise In Humans

Rådegran, G. Ultrasound Doppler estimates of femoral artery blood flow during dynamic knee extensor exercise in humans. J. Appl. Physiol.83(4): 1383–1388, 1997.—Ultrasound Doppler has been used to measure arterial inflow to a human limb during intermittent static contractions. The technique, however, has neither been thoroughly validated nor used during dynamic exercise. In this study, the inherent problems of the technique have been addressed, and the accuracy was improved by storing the velocity tracings continuously and calculating the flow in relation to the muscle contraction-relaxation phases. The femoral arterial diameter measurements were reproducible with a mean coefficient of variation within the subjects of 1.2 ± 0.2%. The diameter was the same whether the probe was fixed or repositioned at rest (10.8 ± 0.2 mm) or measured during dynamic exercise. The blood velocity was sampled over the width of the diameter and the parabolic velocity profile, since sampling in the center resulted in an overestimation by 22.6 ± 9.1% ( P< 0.02). The femoral arterial Doppler blood flow increased linearly ( r = 0.997, P < 0.001) with increasing load [Doppler blood flow = 0.080 ⋅ load (W) + 1.446 l/min] and was correlated positively with simultaneous thermodilution venous outflow measurements ( r = 0.996, P < 0.001). The two techniques were linearly related (Doppler = thermodilution ⋅ 0.985 + 0.071 l/min; r = 0.996, P < 0.001), with a coefficient of variation of ∼6% for both methods.

Effect of contraction frequency on leg blood flow during knee extension exercise in humans

2001 ◽  
Vol 91 (2) ◽  
pp. 671-679 ◽  
Author(s):  
Brian D. Hoelting ◽  
Barry W. Scheuermann ◽  
Thomas J. Barstow
Keyword(s):  
Blood Flow ◽  
Doppler Ultrasound ◽  
Femoral Artery ◽  
Supine Position ◽  
Muscle Blood Flow ◽  
Muscle Tension ◽  
Knee Extension ◽  
Contraction Frequency ◽  
Knee Extension Exercise ◽  
Exercise In Humans

Previous studies in isolated muscle preparations have shown that muscle blood flow becomes compromised at higher contraction frequencies. The purpose of this study was to examine the effect of increases in contraction frequency and muscle tension on mean blood flow (MBF) during voluntary exercise in humans. Nine male subjects [23.6 ± 3.7 (SD) yr] performed incremental knee extension exercise to exhaustion in the supine position at three contraction frequencies [40, 60, and 80 contractions/min (cpm)]. Mean blood velocity of the femoral artery was determined beat by beat using Doppler ultrasound. MBF was calculated by using the diameter of the femoral artery determined at rest using echo Doppler ultrasound. The work rate (WR) achieved at exhaustion was decreased ( P< 0.05) as contraction frequency increased (40 cpm, 16.2 ± 1.4 W; 60 cpm, 14.8 ± 1.4 W; 80 cpm, 13.2 ± 1.3 W). MBF was similar across the contraction frequencies at rest and during the first WR stage but was higher ( P < 0.05) at 40 than 80 cpm at exercise intensities >5 W. MBF was similar among contraction frequencies at exhaustion. In humans performing knee extension exercise in the supine position, muscle contraction frequency and/or muscle tension development may appreciably affect both the MBF and the amplitude of the contraction-to-contraction oscillations in muscle blood flow.

Muscle Capillary and Femoral Artery Blood Flow Kinetics following the Onset of Exercise

2006 ◽  
Vol 38 (Supplement) ◽  
pp. S196-S197
Author(s):  
Allison J. Harper ◽  
Leonardo F. Ferreira ◽  
Barbara J. Lutjemeier ◽  
Dana K. Townsend ◽  
Thomas J. Barstow
Keyword(s):  
Blood Flow ◽  
Femoral Artery ◽  
Artery Blood Flow ◽  
Femoral Artery Blood Flow
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