Effects of a prior high-intensity knee-extension exercise on muscle recruitment and energy cost: a combined local and global investigation in humans

2009 ◽  
Vol 94 (6) ◽  
pp. 704-719 ◽  
Author(s):  
Gwenael Layec ◽  
Aurélien Bringard ◽  
Yann Le Fur ◽  
Christophe Vilmen ◽  
Jean-Paul Micallef ◽  
...  
Keyword(s):  
Energy Cost ◽  
High Intensity ◽  
Knee Extension ◽  
Muscle Recruitment ◽  
Knee Extension Exercise

Influence of endurance training on muscle [PCr] kinetics during high-intensity exercise

2007 ◽  
Vol 293 (1) ◽  
pp. R392-R401 ◽  
Author(s):  
Andrew M. Jones ◽  
Daryl P. Wilkerson ◽  
Nicolas J. Berger ◽  
Jonathan Fulford
Keyword(s):  
Endurance Training ◽  
High Intensity ◽  
Slow Component ◽  
Knee Extension ◽  
High Intensity Exercise ◽  
Whole Body ◽  
Time To Exhaustion ◽  
Exercise Tests ◽  
Before And After ◽  
Knee Extension Exercise

We hypothesized that a period of endurance training would result in a speeding of muscle phosphocreatine concentration ([PCr]) kinetics over the fundamental phase of the response and a reduction in the amplitude of the [PCr] slow component during high-intensity exercise. Six male subjects (age 26 ± 5 yr) completed 5 wk of single-legged knee-extension exercise training with the alternate leg serving as a control. Before and after the intervention period, the subjects completed incremental and high-intensity step exercise tests of 6-min duration with both legs separately inside the bore of a whole-body magnetic resonance spectrometer. The time-to-exhaustion during incremental exercise was not changed in the control leg [preintervention group (PRE): 19.4 ± 2.3 min vs. postintervention group (POST): 19.4 ± 1.9 min] but was significantly increased in the trained leg (PRE: 19.6 ± 1.6 min vs. POST: 22.0 ± 2.2 min; P < 0.05). During step exercise, there were no significant changes in the control leg, but end-exercise pH and [PCr] were higher after vs. before training. The time constant for the [PCr] kinetics over the fundamental exponential region of the response was not significantly altered in either the control leg (PRE: 40 ± 13 s vs. POST: 43 ± 10 s) or the trained leg (PRE: 38 ± 8 s vs. POST: 40 ± 12 s). However, the amplitude of the [PCr] slow component was significantly reduced in the trained leg (PRE: 15 ± 7 vs. POST: 7 ± 7% change in [PCr]; P < 0.05) with there being no change in the control leg (PRE: 13 ± 8 vs. POST: 12 ± 10% change in [PCr]). The attenuation of the [PCr] slow component might be mechanistically linked with enhanced exercise tolerance following endurance training.

Effects of creatine supplementation on the energy cost of muscle contraction: a 31P-MRS study

1999 ◽  
Vol 87 (1) ◽  
pp. 116-123 ◽  
Author(s):  
Sinclair A. Smith ◽  
Scott J. Montain ◽  
Ralph P. Matott ◽  
Gary P. Zientara ◽  
Ferenc A. Jolesz ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Energy Cost ◽  
Creatine Supplementation ◽  
Exercise Bout ◽  
Knee Extension ◽  
Resonance System ◽  
Exercise Protocol ◽  
Dynamic Contractions ◽  
Placebo Trial ◽  
Knee Extension Exercise

Five women and 3 men (29.8 ± 1.4 yr) performed dynamic knee-extension exercise inside a magnetic resonance system (means ± SE). Two trials were performed 7–14 days apart, consisting of a 4- to 5-min exhaustive exercise bout. To determine quadriceps cost of contraction, brief static and dynamic contractions were performed pre- and postexercise.31P spectra were used to determine pH and relative concentrations of Pi, phosphocreatine (PCr), and βATP. Subjects consumed 0.3 g ⋅ kg−1 ⋅ day−1of a placebo ( trial 1) or creatine ( trial 2) for 5 days before each trial. After creatine supplementation, resting ΔPCr increased from 40.7 ± 1.8 to 46.6 ± 1.1 mmol/kg ( P = 0.04) and PCr during exercise declined from −29.6 ± 2.4 to −34.1 ± 2.8 mmol/kg ( P = 0.02). Muscle static (ΔATP/N) and dynamic (ΔATP/J) costs of contraction were unaffected by creatine supplementation as well as were ATP, Pi, pH, PCr resynthesis rate, and muscle strength and endurance. ΔATP/J and ΔATP/N were greatest at the onset of the exercise protocol ( P< 0.01). In summary, creatine supplementation increased muscle PCr concentration, which did not affect muscle ATP cost of contraction.

Vascular function is related to blood flow during high-intensity, but not low-intensity, knee extension exercise

2020 ◽  
Vol 128 (3) ◽  
pp. 698-708 ◽  
Author(s):  
Brady E. Hanson ◽  
Meagan Proffit ◽  
Jayson R. Gifford
Keyword(s):  
Blood Flow ◽  
High Intensity ◽  
Vascular Function ◽  
Knee Extension ◽  
Work Rate ◽  
Microvascular Function ◽  
Blood Flow Response ◽  
Low Intensity ◽  
Flow Response ◽  
Knee Extension Exercise

While vascular function, assessed as the ability of the vasculature to dilate in response to a stimulus, is related to cardiovascular health, its relationship to exercise hyperemia is unclear. This study sought to determine if blood flow during submaximal and maximal exercise is related to vascular function. Nineteen healthy adults completed multiple assessments of vascular function specific to the leg, including passive leg movement (PLM), rapid onset vasodilation (ROV), reactive hyperemia (RH), and flow-mediated dilation (FMD). On a separate day, exercise blood flow (Doppler ultrasound) was assessed in the same leg during various intensities of single-leg, knee-extension (KE) exercise. Vascular function, determined by PLM, ROV, and RH, was related to exercise blood flow at high intensities, including maximum work rate (WRmax) ( r = 0.58–0.77, P < 0.001), but not low intensities, like ~21% WRmax ( r = 0.12–0.34, P = 0.12–0.62). Relationships between multiple indices of vascular function and peak exercise blood flow persisted when controlling for quadriceps mass and exercise work rate ( P < 0.05), indicating vascular function is independently related to the blood flow response to intense exercise. When divided into two groups based upon the magnitude of the PLM response, subjects with a lower PLM response exhibited lower exercise flow at several absolute work rates, as well as lower peak flow ( P < 0.05). In conclusion, leg flow during dynamic exercise is independently correlated with multiple different indices of microvascular function. Thus microvascular function appears to modulate the hyperemic response to high-intensity, but not low-intensity, exercise. NEW & NOTEWORTHY While substantial evidence indicates that individuals with lower vascular function are at greater risk for cardiovascular disease, with many redundant vasodilator pathways present during exercise, it has been unclear if low vascular function actually impacts blood flow during exercise. This study provides evidence that vascular function, assessed by multiple noninvasive methods, is related to the blood flow response to high-intensity leg exercise in healthy young adults. Importantly, healthy young adults with lower levels of vascular function, particularly microvascular function, exhibit lower blood flow during high-intensity, and maximal knee extension exercise. Thus it appears that in addition to increasing one’s risk of cardiovascular disease, lower vascular function is also related to a blunted blood flow response during high-intensity exercise.

scholarly journals Effects of prior exercise on oxygen uptake and phosphocreatine kinetics during high‐intensity knee‐extension exercise in humans

2001 ◽  
Vol 537 (1) ◽  
pp. 291-303 ◽  
Author(s):  
H. B. Rossiter ◽  
S. A. Ward ◽  
J. M. Kowalchuk ◽  
F. A. Howe ◽  
J. R. Griffiths ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
High Intensity ◽  
Knee Extension ◽  
Prior Exercise ◽  
Knee Extension Exercise ◽  
Exercise In Humans

Prior heavy knee extension exercise does not affect $$\dot{V}\hbox{O}_{2}$$ kinetics during subsequent heavy cycling exercise

2007 ◽  
Vol 102 (4) ◽  
pp. 481-491 ◽  
Author(s):  
John R. Thistlethwaite ◽  
Benjamin C. Thompson ◽  
Joaquin U. Gonzales ◽  
Barry W. Scheuermann
Keyword(s):  
Knee Extension ◽  
Cycling Exercise ◽  
Knee Extension Exercise

Designing and Usability testing of a New Prototype Active Footrest for Knee Extension Exercise Among Office Workers

2021 ◽  
pp. 1-16
Author(s):  
Mostafa Mohammadian ◽  
Alireza Choobineh ◽  
Mohsen Razeghi ◽  
Naser Hashemi Nejad ◽  
M.R. Karamooz-Ravari ◽  
...  
Keyword(s):  
Usability Testing ◽  
Knee Extension ◽  
Office Workers ◽  
Knee Extension Exercise

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.

Can Hip Joint Position affect Quadriceps Muscle Responses during Knee Extension Exercise?

2020 ◽  
Vol 41 (13) ◽  
pp. 929-935
Author(s):  
Denis César Leite Vieira ◽  
Marco Aurélio Araujo Dourado ◽  
Lucas Ugliara ◽  
Joao Luiz Quagliotti Durigan ◽  
Brad J. Schoenfeld ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Muscle Thickness ◽  
Rectus Femoris ◽  
Peak Torque ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Knee Extensors ◽  
Work Output ◽  
Before And After ◽  
Knee Extension Exercise

AbstractThis study investigated the acute effects of seated and supine knee extension exercise on muscle swelling, torque, and work output. Twelve resistance-trained men performed two isokinetic concentric-only knee-extension training protocols at different hip positions in a counter-balanced order. They completed the knee extension exercise in the seated (hip angle at 85°) and supine (hip angle at 180°) positions. The torque and work output were assessed during each set. Moreover, muscle thickness of the middle and proximal vastus lateralis and rectus femoris were evaluated before and after each protocol and used as an indicator of muscle swelling. Middle rectus femoris and proximal vastus lateralis thickness increased significantly (p=0.01) with no difference between exercise variations. However, the middle vastus lateralis thickness increased (p=0.01) only after the seated knee extension exercise (~7%). Knee extensors’ peak torque and work output were approximately 8% higher (p=0.04) in the seated when compared to the supine hip position. There was a similar decrease in torque and work output throughout both protocols (p=0.98). In conclusion, seated knee extension exercises produced greater torque, work output, and muscle swelling in the vastus lateralis when compared to the supine knee extension exercise.

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