Littérature scientifique sur le sujet « VO2p kinetic »
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Articles de revues sur le sujet "VO2p kinetic"
1
Grassi, B., D. C. Poole, R. S. Richardson, D. R. Knight, B. K. Erickson et P. D. Wagner. « Muscle O2 uptake kinetics in humans : implications for metabolic control ». Journal of Applied Physiology 80, no 3 (1 mars 1996) : 988–98. http://dx.doi.org/10.1152/jappl.1996.80.3.988.
Texte intégralRésumé :
Muscle O2 uptake (VO2) kinetics in response to an augmented energetic requirement (on-transition) has never been directly determined in humans. We have developed a constant-infusion thermodilution technique that allowed rapid measurements of leg blood flow (Qleg) and, in conjunction with frequent serial measurement of arteriovenous O2 content difference across the leg [(Ca - Cv)O2leg], permitted the determination of the VO2 of the leg (VO2leg) at 3- to 4-s time intervals. VO2leg kinetics during the on-transition was taken as a close approximation of muscle VO2 (VO2mus) kinetics. Alveolar VO2 (VO2A), Qleg, leg O2 delivery [(Q.CaO2leg)], (Ca - Cv)O2leg, and VO2leg kinetics were determined in six trained subjects [age 22.8 +/- 4.4 (SD) yr; maximal O2 uptake 59.1 +/- 5.3 ml.kg-1.min-1] during the transition from unloaded pedaling to a workload (loaded pedaling; LP) (183 +/- 20 W) well below the previously determined ventilatory threshold. For all variables, two distinct phases were recognized. During the first 10-15 s of loaded pedaling (phase I), VO2A, Qleg, and (Q.CaO2)leg increased rapidly, whereas VO2leg increased only slightly and (Ca - Cv)O2leg actually decreased. After phase I, all variables showed a monoexponential increase (phase II), with similar time courses [slightly faster for (Ca - CV)O2leg]. In a consideration of both phases, the half times of the responses among variables were not significantly different: 25.5 +/- 2.6 s for VO2A, 26.6 +/- 7.6 s for Qleg, 26.9 +/- 8.3 s for (Q.CaO2leg, 23.5 +/- 1.3 s for (Ca - Cv)O2leg, and 27.9 +/- 5.7 s for VO2leg. We conclude that during the on-transition the kinetics of VO2A and VO2leg, as measured by these methods, are similar. The analysis of the early phase (first 10-15 s) of the on-transition indicates that bulk delivery of O2 to the working muscles is not limiting VO2leg kinetics. However, the present results cannot discriminate between maldistribution of blood flow/VO2 vs. inertia the intracellular oxidative machinery as the limiting factor.
2
Stathokostas, Liza, John M. Kowalchuk, Robert J. Petrella et Donald H. Paterson. « Moderate and heavy oxygen uptake kinetics in postmenopausal women ». Applied Physiology, Nutrition, and Metabolism 34, no 6 (décembre 2009) : 1065–72. http://dx.doi.org/10.1139/h09-107.
Texte intégralRésumé :
The lack of estrogen in postmenopausal women not using hormone replacement therapy (HRT), compared with those using HRT, may reduce submaximal blood flow during exercise and result in an oxygen delivery limitation constraining oxygen uptake (VO2) kinetics. The adaptation of pulmonary VO2 (VO2p) during the transition to exercise in older women was examined in this study. Thirty-one healthy postmenopausal women (mean age, 61 ± 6 years), 15 not using HRT and 16 using HRT, performed repeated exercise transitions (6 min) on a cycle, to work rates corresponding to 80% of estimated ventilatory threshold (moderate-intensity exercise) and to Δ50 (heavy-intensity exercise). There was no difference in moderate-intensity τVO2p between non-HRT (40 ± 9 s) and HRT (41 ± 9 s) women. Similarly, there was no difference in heavy-intensity τVO2p between non-HRT (44 ± 8 s) and HRT (45 ± 8 s) women. Thus, HRT did not affect the slowing of VO2 kinetics of older women.
3
Buekers, Joren, Jan Theunis, Alberto Peña Fernández, Emiel F. M. Wouters, Martijn A. Spruit, Patrick De Boever et Jean-Marie Aerts. « Box-Jenkins Transfer Function Modelling for Reliable Determination of VO2 Kinetics in Patients with COPD ». Applied Sciences 9, no 9 (1 mai 2019) : 1822. http://dx.doi.org/10.3390/app9091822.
Texte intégralRésumé :
Oxygen uptake (VO2) kinetics provide information about the ability to respond to the increased physical load during a constant work rate test (CWRT). Box-Jenkins transfer function (BJ-TF) models can extract kinetic features from the phase II VO2 response during a CWRT, without being affected by unwanted noise contributions (e.g., phase I contribution or measurement noise). CWRT data of 18 COPD patients were used to compare model fits and kinetic feature values between BJ-TF models and three typically applied exponential modelling methods. Autocorrelation tests and normalised root-mean-squared error values (BJ-TF: 2.8 ± 1.3%; exponential methods A, B and C: 10.5 ± 5.8%, 11.3 ± 5.2% and 12.1 ± 7.0%; p < 0.05) showed that BJ-TF models, in contrast to exponential models, could account for the most important noise contributions. This led to more reliable kinetic feature values compared to methods A and B (e.g., mean response time (MRT), BJ-TF: 74 ± 20 s; methods A-B: 100 ± 56 s–88 ± 52 s; p < 0.05). Only exponential modelling method C provided kinetic feature values comparable to BJ-TF features values (e.g., MRT: 75 ± 20 s). Based on theoretical considerations, we recommend using BJ-TF models, rather than exponential models, for reliable determinations of VO2 kinetics.
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Larson, Rebecca D., Monica Barton, John W. Farrell III, Gregory S. Cantrell, David J. Lantis, Christopher D. Black et Carl J. Ade. « Evaluation of Oxygen Uptake Kinetic Asymmetries in Patients with Multiple Sclerosis : A Pilot Study ». International Journal of Kinesiology and Sports Science 6, no 4 (31 octobre 2018) : 21. http://dx.doi.org/10.7575/aiac.ijkss.v.6n.4p.21.
Texte intégralRésumé :
Background of Study: Observations of limb to limb differences (bilateral asymmetry) in leg strength, power, peak oxygen uptake (VO2) and bone mineral density has been reported in individuals with Multiple Sclerosis (MS). Objetives: The purpose of this study was to quantify the magnitude of bilateral asymmetries in oxygen uptake (VO2) kinetics response to single leg cycling (SLC) in relapsing-remitting multiple sclerosis (MS) patients. Methods: Five MSpatients (2 men, 3 women; age 43±7 yrs) performed constant work rate SLC trials to determine VO2 kinetics in each leg. Asymmetry scores were used to quantify the magnitude of the bilateral asymmetries. Results: Significant asymmetries were seen in VO2 peak and parameters of VO2 kinetics. VO2peak asymmetry score was significantly different than 0% (p=0.015). Similarly,significant asymmetry for VO2 kinetic response to exercise as mean response time was observed (p=0.03). In addition the VO2 response to exercise resulted in a significant asymmetry in VO2 deficit between legs (p=0.03). No correlation between EDSS scores and any asymmetry scores existed. Conclusions: These findings provide insight into the potential differences in metabolic perturbation and limb specific symptomatic fatigue within the MS population.
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Cleland, Sarah Margaret, Juan Manuel Murias, John Michael Kowalchuk et Donald Hugh Paterson. « Effects of prior heavy-intensity exercise on oxygen uptake and muscle deoxygenation kinetics of a subsequent heavy-intensity cycling and knee-extension exercise ». Applied Physiology, Nutrition, and Metabolism 37, no 1 (février 2012) : 138–48. http://dx.doi.org/10.1139/h11-143.
Texte intégralRésumé :
This study examined the effects of prior heavy-intensity exercise on the adjustment of pulmonary oxygen uptake (VO2p) and muscle deoxygenation Δ[HHb] during the transition to subsequent heavy-intensity cycling (CE) or knee-extension (KE) exercise. Nine young adults (aged 24 ± 5 years) performed 4 repetitions of repeated bouts of heavy-intensity exercise separated by light-intensity CE and KE, which included 6 min of baseline exercise, a 6-min step of heavy-intensity exercise (H1), 6-min recovery, and a 6-min step of heavy-intensity exercise (H2). Exercise was performed at 50 r·min–1 or contractions per minute per leg. Oxygen uptake (VO2) mean response time was ∼20% faster (p < 0.05) during H2 compared with H1 in both modalities. Phase 2 time constants (τ) were not different between heavy bouts of CE (H1, 29.6 ± 6.5 s; H2, 28.0 ± 4.6 s) or KE exercise (H1, 31.6 ± 6.7 s; H2, 29.8 ± 5.6 s). The VO2 slow component amplitude was lower (p < 0.05) in H2 in both modalities (CE, 0.19 ± 0.06 L·min–1; KE, 0.12 ± 0.07 L·min–1) compared with H1 (CE, 0.29 ± 0.09 L·min–1; KE, 0.18 ± 0.07 L·min–1), with the contribution of the slow component to the total VO2 response reduced (p < 0.05) in H2 during both exercise modes. The effective τHHb was similar between bouts for CE (H1, 18.2 ± 3.0 s; H2, 18.0 ± 3.6 s) and KE exercise (H1, 26.0 ± 7.0 s; H2, 24.0 ± 5.8 s). The ΔHHb slow component was reduced during H2 in both CE and KE (p < 0.05). In conclusion, phase 2 VO2p was unchanged with priming exercise; however, a faster mean response time of VO2p during the heavy-intensity exercise preceded by a priming heavy-intensity exercise was attributed to a smaller slow component and reduced muscle deoxygenation indicative of improved muscle O2 delivery during the second bout of exercise.
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Morton, R. H. « Delayed or accelerated oxygen uptake kinetics in the transition from prior exercise ? » Journal of Applied Physiology 62, no 2 (1 février 1987) : 844–46. http://dx.doi.org/10.1152/jappl.1987.62.2.844.
Texte intégralRésumé :
Reported experimental findings are at variance with each other on the question as to whether O2 uptake (VO2) kinetics are delayed, advanced, or remain unaltered in the transition from prior exercise. Critical examination of these studies tend to suggest that not a great deal of reliance can be placed on their evidence in attempting to resolve the question. They seem to display a disregard for the theoretical properties of the VO2 kinetic model used; in some cases incorrect statistical inferences appear to have been made; most are mathematically incomplete; and the experimental designs have not been appropriately chosen so as to examine the whole question of altered VO2 kinetics. These points are detailed and discussed so that future designed experiments obtain sufficient reliable evidence with which to resolve the question.
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Shoemaker, J. K., L. Hodge et R. L. Hughson. « Cardiorespiratory kinetics and femoral artery blood velocity during dynamic knee extension exercise ». Journal of Applied Physiology 77, no 6 (1 décembre 1994) : 2625–32. http://dx.doi.org/10.1152/jappl.1994.77.6.2625.
Texte intégralRésumé :
The kinetics of femoral artery mean blood velocity (MBV; measured by pulsed Doppler) and whole body oxygen uptake (VO2; measured breath by breath) were assessed from the time constant during the on (tau on) and off (tau off) transients to step changes in work rate between complete rest and dynamic knee extension (KE) exercise. Six healthy men performed 5 min of seated KE exercise, with each leg alternately raising and lowering a weight (10% maximum voluntary contraction) over a 2-s duty cycle. Because kinetic analysis of VO2 kinetics during KE exercise is a new approach, the VO2 responses were also evaluated during the on and off transitions to the more familiar upright cycling exercise in which the magnitude of increase in VO2 and cardiac output was similar to that during KE exercise. During KE exercise, VO2 tau on [mean 72.2 +/- 11.2 (SE) s] was slower than VO2 tau off (33.3 +/- 1.8 s; P < 0.01). Cardiac output, measured with impedance cardiography, was not different for tau on (67.1 +/- 20.0 s) compared with that for tau off (52.9 +/- 7.6 s). Likewise, MBV tau on (34.5 +/- 3.9 s) was not different from tau off (35.3 +/- 3.2 s). During cycling, the VO2 tau on (18.0 +/- 2.4 s) and tau off (30.7 +/- 1.2 s) were both faster than KE VO2 tau on (P < 0.01). Even though the MBV kinetics indicated a rapid adaptation of blood flow during KE exercise, there was a slow adaptation of VO2. A transient hyperemia immediately on cessation of KE exercise, indicated by both MBV and calculated systemic vascular conductance responses, suggested that blood flow might have been inadequate and could have contributed to the delayed adaptation of VO2 at the onset of exercise, although other explanations are possible.
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Hughson, R. L., J. E. Cochrane et G. C. Butler. « Faster O2 uptake kinetics at onset of supine exercise with than without lower body negative pressure ». Journal of Applied Physiology 75, no 5 (1 novembre 1993) : 1962–67. http://dx.doi.org/10.1152/jappl.1993.75.5.1962.
Texte intégralRésumé :
The kinetics of oxygen uptake (VO2) were observed at the onset of submaximal cycling exercise in seven men and one woman [mean age 22.6 +/- 0.9 (SE) yr] in the upright and supine positions and the supine position with -40 mmHg lower body negative pressure (LBNP). There was no significant difference for peak VO2 and ventilatory threshold between the supine (3,081 +/- 133 and 1,954 +/- 138 ml/min, respectively) and the supine + LBNP positions (3,062 +/- 152 and 1,973 +/- 122 ml/min); however, both were reduced compared with upright exercise (3,483 +/- 200 and 2,353 +/- 125 ml/min). Kinetic analysis applied to six repetitions by each subject indicated a slowing from a mean total lag time (time required to achieve 63% of the difference in VO2 between baseline and new steady state) of 36.3 +/- 2.7 s in upright exercise to 44.1 +/- 3.5 s in the supine position. However, total lag time for the supine + LBNP position (36.0 +/- 2.8 s) did not differ from upright exercise but was significantly faster than supine exercise. These data have been interpreted in support of an O2 transport limitation to VO2 kinetics at the onset of supine exercise that is countered by LBNP, likely through a more rapid increase in perfusion to the exercising muscle at these submaximal work rates.
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Xing, H. C., J. E. Cochrane, Y. Yamamoto et R. L. Hughson. « Frequency domain analysis of ventilation and gas exchange kinetics in hypoxic exercise ». Journal of Applied Physiology 71, no 6 (1 décembre 1991) : 2394–401. http://dx.doi.org/10.1152/jappl.1991.71.6.2394.
Texte intégralRésumé :
The kinetics of O2 up-take (VO2), CO2 output (VCO2), ventilation (VE), and heart rate (HR) were studied during exercise in normoxia and hypoxia [inspired O2 fraction (FIO2) 0.14]. Eight male subjects each completed 6 on- and off-step transitions in work rate (WR) from low (25 W) to moderate (100–125 W) levels and a pseudorandom binary sequence (PRBS) exercise test in which WR was varied between the same WRs. Breath-by-breath data were linearly interpolated to yield 1-s values. After the first PRBS cycle had been omitted as a warm-up, five cycles were ensemble-averaged before frequency domain analysis by standard Fourier methods. The step data were fit by a two-component (three for HR) exponential model to estimate kinetic parameters. In the steady state of low and moderate WRs, each value of VO2, VCO2, VE, and HR was significantly greater during hypoxic than normoxic exercise (P less than 0.05) with the exception of VCO2 (low WR). Hypoxia slowed the kinetics of VO2 and HR in on- and off-step transitions and speeded up the kinetics of VCO2 and VE in the on-transition and of VE in the off-transition. Frequency domain analysis confined to the range of 0.003–0.019 Hz for the PRBS tests indicated reductions in amplitude and greater phase shifts in the hypoxic tests for VO2 and HR at specific frequencies, whereas amplitude tended to be greater with little change in phase shift for VCO2 and VE during hypoxic tests.(ABSTRACT TRUNCATED AT 250 WORDS)
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Lin, Xueyan, Wenyue Li, Xuan Pan, Shu Wang et Zhaoyang Fan. « Electrocatalytic and Conductive Vanadium Oxide on Carbonized Bacterial Cellulose Aerogel for the Sulfur Cathode in Li-S Batteries ». Batteries 9, no 1 (26 décembre 2022) : 14. http://dx.doi.org/10.3390/batteries9010014.
Texte intégralRésumé :
Many transition-metal-oxide-based catalysts have been investigated to chemically bind soluble lithium polysulfides and accelerate their redox kinetics in lithium-sulfur (Li-S) battery chemistry. However, the intrinsic poor electrical conductivities of these oxides restrict their catalytic performance, consequently limiting the sulfur utilization and the rate performance of Li-S batteries. Herein, we report a freestanding electrocatalytic sulfur host consisting of hydrogen-treated VO2 nanoparticles (H-VO2) anchored on nitrogen-doped carbonized bacterial cellulose aerogels (N-CBC). The hydrogen treatment enables the formation and stabilization of the rutile VO2(R) phase with metallic conductivity at room temperature, significantly enhancing its catalytic capability compared to the as-synthesized insulative VO2(M) phase. Several measurements characterize the electrocatalytic performance of this unique H-VO2@N-CBC structure. In particular, the two kinetic barriers between S8, polysulfides, and Li2S are largely reduced by 28.2 and 43.3 kJ/mol, respectively. Accordingly, the Li-S battery performance, in terms of sulfur utilization and charge/discharge rate, is greatly improved. This work suggests an effective strategy to develop conductive catalysts based on a typical transition metal oxide (VO2) for Li-S batteries.
Thèses sur le sujet "VO2p kinetic"
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Draper, Stephen B. « VO2 kinetics in severe intensity running ». Thesis, University of Chichester, 2002. http://eprints.chi.ac.uk/799/.
Texte intégralRésumé :
This thesis aimed to investigate and model the vo2, response to exhaustive constant intensity running of a short duration. Study I was a Douglas bag based study that compared the vo2, response of physically active subjects to 2, 5 and 8 minute bouts of constant intensity exhaustive exercise performed in both cycling and running. Nine male subjects took part and each completed a ramp test in addition to the three constant intensity tests in both modes of exercise. In the 5 and 8minute tests the subjects achieved 97.0 ± 4.2 and 97.5 ± 2.0 % for cycling, and 98.5 ± 1.8 and 99.2 ± 2.3% for running, of the ramp test Vo,peak. In the 2 minute test, a significantly lower percentage was attained (89.9 ± 5.5% and 91.8 ± 2.5% for cycling and running respectively). In cycling VO, was still increasing over the final minute of the test, whereas in running there was no difference between the last two 30 second samples (P~0.98). It was concluded that in severe intensity exercise of a short duration VO2 may not achieve its maximum and· that in running it may plateau at this sub-maximal rate. Study 2 validated the QP9000 for the measurement of vo2, during running on a breath-by-breath basis. Six male subjects performed a ramp test and tests at rest and at moderate and severe intensities. Each test was performed twice, once using the QP9000 and once using a Douglas bag system. No difference was found for VO, between the two systems (P~0.358). The SD of the differences between the systems across exercise intensities was 97 ± 57 ml.min·1 It was concluded that the QP9000 provides a valid measure of VO, at all exercises intensities. Study 3 investigated the vo2, response of trained runners to 800 m pace running, following a track based time trial. Eight male subjects (Vo,max 68.8 ± 5.6 m1.kg·'min-') took part in the study. That vo2, reached a plateau below Vo, was confirmed by a gradient of -29 ± 275 ml.min-' during the final 30 seconds of exercise. The asymptotic vo2, was only 85.3 ± 6.6 % of the Vo,peak from a ramp test and the response was shown to be extremely fast (time constant (T) of 10.7 ± 3.4 seconds). These breath-by-breath data confirmed the response indicated in Study I. Study 4 explored the single exponential model used to describe the vo2, response and the nature and level of breath-by-breath noise in severe intensity running. Five male subjects performed a ramp test to determine the speed at anaerobic threshold (AT). Each subject then performed five 8-minute runs at a speed corresponding to 90% of the AT and five exhaustive runs at a speed that would elicit exhaustion in about 2-minutes. Analysis of the noise to signal ratio of the severe intensity data showed that the noise was Gaussian and that averaging data over repeated transitions reduced this ratio. Computer simulations of noise equivalent to the noisiest subject's data demonstrated that the use of two repeated severe intensity transitions would give 95% confidence limits of < ± 1.2 seconds for T. Study 5 examined the effect of prior supra AT exercise on the VO, response to exhaustive severe intensity running. Ten middle and long distance runners each completed a ramp test to determine AT and Vo,peak. Subjects then ran exhaustive transitions, lasting approximately 2-minutes, that were preceded by moderate (90% AT) or heavy (50% of the difference between AT and Vo,peak) intensity running. Each transition was repeated. Increased metabolic acidosis (from prior heavy intensity exercise) did not increase the asymptotic vo2, (P ~ 0.226), and this figure represented only about 90% of Vo,peak from the ramp test. The mean response time (MRT) (time to reach 63% of the overall response) was faster following heavy exercise (20.9 ± 1.9 s vs. 18.9 ± 1.0 s, P<0.05). This was however due to a reduction in the duration of the initial (cardiodynamic) phase of the response rather than a speeding of the primary (phase 2) kinetics. Study 6 analysed the differences in this response between sprint and endurance runners. Six male athletes were recruited for each group based on best times for 100 m and 10 000 m. Subjects performed repeated transitions at a speed that would elicit exhaustion in approximately 2-minutes. No difference was found in the model of the VO, response between groups. When all subjects were analysed however a strong negative relationship was demonstrated between Vo,peak (from a ramp test) and the percentage of this Vo,peak that was reached in the constant speed test (r ~ -0.811, P ~ 0.001). It was concluded that the VO, response was dependent on the aerobic capabilities of the individual. In conclusion the thesis demonstrated a vo2, response in trained subjects during exhaustive severe intensity running that was different to that which is suggested by the majority of the literature. The vo2, response tends neither to VO, required nor to Vo,max, but rather tends to a plateau that is sub-maximal. This thesis was unable to identity the mechanisms that might result in such a shortfall in the response. However there appears to be a close link with the aerobic capabilities of the individual.
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Lindblom, Hampus. « VO2-kinetik vid arm- och benarbete samt bara benarbete ». Thesis, Mittuniversitetet, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-9203.
Texte intégralRésumé :
Kroppens syreupptagningskinetik innebär hur snabbt syreupptagningsmekanismerna i kroppen ökar mängden upptaget syre (O2) vid ett påbörjat arbete. Detta påverkar oss dagligen genom att en snabbare reaktion leder till en mindre syreskuld efter arbetet. Syftet med studien var att jämföra VO2-kinetiken mellan ett arm- och benarbete och ett rent benarbete och försöka hitta skillnader mellan dessa. Åtta måttligt tränade försökspersoner (sex män och två kvinnor) rekryterades och fick genomgå tre tester på en specialbyggd arm- och bencykelergometer. Testerna bestod av ett VO2-maxtest (kombinerad arm- och benarbete), ett submaximalt arm- och bentest (AB) och ett submaximal bentest (B) på samma absolut arbetsintensitet (65 % av VO2max) där VO2-kinetik mättes under fyra minuters arbete. Tiden att nå 50 % av VO2-platå (tVO250) var lika mellan AB och B-test (p=0.70). Tiden till VO2-platå var 19 % kortare under arm- och benarbete (AB 82 ± 32 vs B 101 (± 24) sek; p=0.02). Förbrukat O2 under testtiden var större under AB test jämfört med B-test (AB 41 ± 4 vs B 38 ± 4 ml · kg-1; p=0.004). Enligt dessa resultat var syrekinetiken under arm- och benarbetet snabbare jämfört med bara benarbetet, vilket betydde i detta fall att syreskulden i början av arbete under kombinerat arm- och benarbete blev mindre.
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DiMenna, Fred J. « The influence of muscle fibre recruitment on VO2 kinetics ». Thesis, University of Exeter, 2010. http://hdl.handle.net/10036/106719.
Texte intégralRésumé :
When O2 uptake at the lung is used to characterise the oxidative metabolic response to increased contractile activity ( O2 kinetics) in exercising muscle, the O2 profile reflects the combined influence of all involved muscle fibres. Consequently, during high-intensity exercise that mandates activation of fibres with considerable metabolic diversity (e.g., both principal fibre types), response characteristics specific to discrete segments of the recruited pool cannot be determined. The purpose of this thesis was to identify fibre-type-specific effects of conditions that might impact O2 delivery and/or motor unit recruitment patterns on O2 kinetics by using two models that increase fibre recruitment homogeneity during exercise transitions. In four experiments, subjects initiated high-intensity exercise from a moderate baseline (i.e., performed ‘work-to-work’ transitions; M→H) to target higher-order fibres, and in two experiments, subjects cycled at extremely slow and fast pedal rates to skew recruitment toward slow- and fast-twitch fibres, respectively. At mid-range contraction frequency, O2 kinetics (as indicated by the primary time constant, τp) was slower for M→H compared to unloaded-to-high-intensity transitions (U→H) (e.g., 42 v. 33 s; Ch 4) and this slowing was ~50% greater for M→H in a supine body position (decreased oxygenation; Ch 6). Slower kinetics was also present for U→H cycling at fast compared to slow pedal rates (τp, 48 v. 31 s; Ch 8). Conversely, M→H slowing relative to U→H was absent at extreme cadences (36 v. 31 s and 53 v. 48 s for slow and fast, respectively; Ch 7). After ‘priming’ (increased oxygenation), τp was reduced for U→H after fast-cadence priming only (Ch 8) and for M→H in the supine position (Ch 6), but unaffected for upright cycle and prone knee-extension M→H, for which priming reduced the O2 slow component and delayed-onset fibre activation (as indicated by iEMG; Chs 4 and 5). These results provide evidence in exercising humans that high-order fibres possess innately slow O2 kinetics and are acutely susceptible to interventions that might alter O2 delivery to muscle.
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Jakaitė, Jurgita. « 18-22 metų merginų, sergančių 1 tipo cukriniu diabetu, greitosios adaptacijos aerobiniams ėjimo krūviams ypatumai ». Master's thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120620_134458-38602.
Texte intégralRésumé :
Hipotezė: 1 tipo cukriniu diabetu sergančių merginų vegetacinių sistemų rodiklių pokyčiai krūvio metu bus didesni, nei šokėjų ir nesportuojančių.
Tikslas: Įvertinti 18-22 1 tipo cukriniu diabetu sergančių merginų, greitosios adaptacijos aerobiniams ėjimo krūviams, ypatumus.
Tiriamieji: 10 šokėjų, 12 nesportuojančių sveikų merginų, ir 12 sergančių 1 tipo cukriniu diabetu merginų.
Tyrimo metodai: 1. Kūno kompozicija 2. dujų analizė 3. pulsometrija 4. biocheminė kraujo analizė 5. standartinis šešių minučių ėjimo krūvis bėgtakiu 6. matematinė statistika.
Tyrimo organizavimas: Tyrimas atliktas 2011-2012 metais. Tyrime dalyvavo 34 merginos, kurios buvo suskirstytos į 3 grupes: I grupę sudarė 1 tipo cukriniu diabetu sergančios merginos (n=12), II grupę šokėjos (n=10), III grupę nesportuojančios sveikos merginos (n=12). Tiriamosios buvo 18-22 metų amžiaus. Tiriamosios, atvykusios į Lietuvos kūno kultūros akademijos sporto fiziologijos labaratorija, buvo supažindintos su tyrimu. Prieš tyrimą tiriamosioms buvo atlikta kūno sudėties analizė su „Tanita TBF-300-A “ svartyklėmis. “Tanita TBF-300-A” svarstyklėmis buvo nustatyta tiriamųjų: kūno masė, KMI (kūno masės indeksas), riebalų masė (%), riebalų masė (kg). Visos tyrime dalyvavusios merginos atliko 6 minučių standartinį ėjimo testą bėgtakiu VIASYS LE 200 CE (Vokietija) pagal (1 tyrimo protokolą). 6 minučių standartinio ėjimo testo metu buvo atliktas tiesioginis MDS nustatymas dujų analizatoriumi „Oxycon Mobile“ (Jaeger, Vokietija)... [toliau žr. visą tekstą]Hypothesis: We thought that type 1 diabetic girls vegetative system parameters during exercise will be higher than the dancers and untrained. The aim of the study: To evaluate the type 1 diabetic quick adaptation of aerobic walking loads, characteristics Subjects: 10 dancers, 12 untrained healthy women, 12 patients with type 1 diabetic women. The methods of the study: 1. Body composition 2. gas analysis 3. pulsometry 4. biochemical blood analysis 5. standard 6-minute treadmill walk test 6. mathematical statistics. The organization of the study: The study was conducted from 2011 to 2012 years. The study included 34 women were divided into 3 groups: group I consisted of type 1 diabetic girls (n = 12), group II dancers (n = 10), III group of healthy untrained girls (n = 12). The participants were between 18-22 years of age. Before the study subjects was performed body composition analysis with Tanita TBF-300-A."Tanita TBF-300-A subjects were found on scales: body weight, BMI (body mass index), fat mass (%), fat mass (kg).All the girls participated in the study, carried out a standard 6-minute treadmill walk test VIASYS LE 200 CE (Germany) in accordance with (1 TABLE). Standard 6-minute walk test was carried out directly by the gas analyzer MDS "Oxycon Mobile (Jaeger, Germany). Total 6-minute walk test in a standard treadmill VIASYS LE 200 CE (Germany) and recovery time using a portable system Oxycon Mobile has been recorded in gas exchange rates of oxygen consumption (VO2)... [to full text]
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McNulty, Craig R. « The complex reality of VO2 kinetics to steady state : Reassessment of the models used to quantify and interpret VO2 kinetics, steady state, and time to steady state ». Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/108025/2/Craig_McNulty_Thesis.pdf.
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This thesis developed new methods of modelling oxygen uptake in exercising humans during cycling exercise sessions to steady-state. The results will contribute to the redefinition of conventional methods of data acquisition, processing, and modelling across exercise physiology, sports science, and respiratory disease research and application. The thesis identified misconceptions within current methods of data handling, and proposed innovative methods for improved data modelling.
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Williams, Christine Suzanne. « The Effect of Running Speed on VO2 Kinetics in the Severe Exercise Domain ». Thesis, University of North Texas, 1997. https://digital.library.unt.edu/ark:/67531/metadc277817/.
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There has been an interest in the kinetics of the V02 response during exercise at various intensities. However, most studies focus on the response of submaximal intensities whereas few studies have examined V02 kinetics at severe intensities. The purpose of this study was to evaluate the effect of exercise intensity on V02 kinetics over a range of severe intensities.
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Updyke, Rhonda S. « The Effect of Mode and Intensity on Vo2 Kinetics in the Severe Intensity Domain ». Thesis, University of North Texas, 2000. https://digital.library.unt.edu/ark:/67531/metadc2493/.
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The purpose of this study was to evaluate the effect of mode and intensity on VO2 kinetics in the severe intensity domain. Seventeen participants completed 3-7 tests each on a cycle ergometer and treadmill. For each test, Tfatigue, VO2max, Tmean response, VO2GAIN, TVO2max and T@VO2max were determined. Linear regression techniques were used to describe the relationship between TVO2max and Tfatigue .
VO2max values were higher in running. The VO2 response profile was faster for running than cycling and faster at higher intensities.
The faster VO2 response in running may be associated with larger active muscle mass or differences in muscle activation patterns. The faster response at higher intensities may suggest that VO2 response is driven by O2 demand.
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Goodwin, Matthew Lawrence Gladden L. Bruce. « VO2 on-kinetics in isolated canine muscle in situ during slowed convective O2 delivery ». Auburn, Ala, 2008. http://hdl.handle.net/10415/1464.
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Aguiar, Rafael Alves de. « Desempenho e fadiga em sprints repetidos : a influência de características fisiológicas e perfil de treinamento ». Universidade do Estado de Santa Catarina, 2013. http://tede.udesc.br/handle/handle/256.
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The aim of this study was to determine the mode and the level that the physiological and performance variables influence in repeated running sprint ability. To this end, the study used 27 males participants (10 sprint runners (VEL), 8 long-distance runners (FUN) and 9 active subjects (ATI)). In a synthetic track these subjects were submitted to following tests on different days: 1) Incremental testing for determination of VO2max and maximal aerobic velocity (MAV); 2) constant velocity test at 110%MAV for determination of on- and off transition kinetics of VO2 and accumulated deficit oxygen (AOD); 3; 1 minute all-out test for determination of blood lactate concentration ([lac]s) kinetics and off-transition kinetics of VO2; and 4) repeated sprint test (10 sprints of 35 m departing every 20 s) for determine the total time of sprints, best sprint and percentage decrement score (Sdec). In every tests the [lac]s and blood pH were analyzed for observe the difference between maximal value after exercise and rest value (i.e. ∆[lac]s e ∆pH).Total time was significant different between all groups (VEL, 49,5 ± 0,9 s; FUN, 52,6 ± 3,1 s; ATI, 55,9s ± 2,6 s) and Sdec was significant lower in long distance runners compared to other groups (VEL, 8,5 ± 2,5%; FUN, 4,0 ± 2,0%; ATI, 8,3 ± 4,1%). Total time was significant correlated with best sprint (r 0,86), AOD in T110 (r = -,061) and T1min (r = -0,60), ∆[lac]s (r = -0,64) and ∆pH (r = 0,59) in RS, primary time constant (tau1) (r = -0,45) e O2 consumed in fast component after exercise in T1min (r = -0,44). Differently, Sdec was significant correlated with aerobic variables (VO2max, r = -0,59; MAV, r = -0,55; tau1 during exercise, r = 0,41), tau1 after T110 (r = 0,59) and T1min (r = 0,47), as well as, with lactate exchange ability (r 0,75). Therefore, it was concluded that repeated sprint performance is strongly influenced by anaerobic characteristics, while mechanisms related to removal of metabolites originated by anaerobic metabolism and aerobic indices influence to decrease fatigue in RS.
O objetivo deste estudo foi determinar o modo e o grau que as variáveis fisiológicas e de desempenho influenciam no desempenho em sprints repetidos. Para este fim, participaram do estudo 27 homens, sendo 10 corredores velocistas (VEL), 8 corredores fundistas (FUN) e 9 sujeitos ativos (ATI). Em uma pista sintética de atletismo estes sujeitos foram submetidos, em dias diferentes, aos seguintes testes: 1) teste incremental para determinação do VO2max e da velocidade aeróbia máxima (MAV); 2) teste de velocidade constante realizado a 110%MAV (T110) para determinar a cinética do VO2 durante e após o exercício e o déficit de oxigênio (AOD); 3) teste de um minuto máximo (T1min), para determinar a cinética da concentração de lactato sanguíneo ([lac]s) e a cinética do VO2 após o exercício; e 4) teste de sprints repetidos (RS) (10 sprints de 35m, intercalados com 20s de recuperação) para determinar o tempo total dos sprints, melhor sprint e a queda do escore em percentual (Sdec). Em todos os testes a [lac]s e o pH sanguíneo foram analisados para observar a diferença entre o valor máximo após o exercício e o valor de repouso (i.e. ∆[lac]s e ∆pH). Tempo total em RS foi significativamente diferente entre todos os grupos (VEL, 49,5 ± 0,9 s; FUN, 52,6 ± 3,1 s; ATI, 55,9s ± 2,6 s) e Sdec foi significativamente inferior em fundistas comparado aos outros grupos (VEL, 8,5 ± 2,5%; FUN, 4,0 ± 2,0%; ATI, 8,3 ± 4,1%). Tempo total foi correlacionado significativamente com o melhor sprint (r = 0,86), com o AOD no T110 (r = -0,61) e no T1min (r = -0,60), com o ∆[lac]s (r = -0,64) e ∆pH (r = 0,59) do RS, com a constante de tempo primária (tau1) (r = -0,45) e O2 consumido pelo componente rápido após o exercício no T1min (r = -0,44). Diferentemente, o Sdec foi correlacionado significativamente com variáveis aeróbias (VO2max, r = -0,59; MAV, r = -0,55; tau1 durante T110, r = 0,41), tau1 após T110 (r = 0,59) e T1min (r = 0,47), bem como, com a constante de tempo da entrada do lactato no compartimento sanguíneo no T1min (r = -0,75). Portanto, foi concluído que o desempenho em sprints repetidos é altamente influenciado por características anaeróbias, enquanto, mecanismos relacionados à remoção dos metabólitos originados pelo metabolismo anaeróbio e índices aeróbios influenciam para diminuir a fadiga em RS.
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Machado, Carlos Eduardo Polazzo [UNESP]. « Efeitos do exercício prévio de intensidade supramáxima sobre a cinética do consumo de oxigênio em ciclistas treinados ». Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/87365.
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machado_cep_me_rcla.pdf: 485625 bytes, checksum: fb01231ed1afbdc33006414cd73d2b07 (MD5)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
O surgimento de equipamentos que permitem a análise do consumo de oxigênio (VO2) respiração-a- respiração, tem despertado um grande interesse nos fatores que podem influenciar sua cinética no início do exercício (resposta on). Entre os fatores mais estudados, temos a intensidade do exercício e o nível do treinamento dos sujeitos. Estes dados sugerem que a influência do exercício prévio sobre o VO2 durante o exercício incremental só ocorreria em baixas intensidades de esforço (< 60% VO2max). Os objetivos deste estudo foram: a) analisar a influência do exercício supramáximo realizado previamente, sobre os parâmetros da cinética do VO2 durante a transição repouso-exercício realizado a 50 e 70% VO2max, e b) analisar a influência do exercício supramáximo realizado previamente sobre as respostas cardiorrespiratórias e metabólicas durante o exercício de carga constante realizado a 50 e 70% VO2max. Para este estudo foram utilizados 14 ciclistas bem treinados do sexo masculino (VO2max = 63,4 + 6,5 ml.kg-1.min-1; idade = 21,4 + 3,5 anos; massa corporal = 68,1 + 6,8 kg; estatura = 174,9 + 4,6 cm) que executaram cinco testes: 1) exercício contínuo progressivo até a exaustão voluntária para a determinação do VO2max e as cargas correspondentes a 50, 70 e 120% VO2max e; 2) Quatro testes de carga constante, executados de forma aleatória e em dias separados. Nestes testes os sujeitos pedalaram durante 20 minutos em duas diferentes intensidades de exercício (50 e 70% do VO2max), realizados com e sem a execução prévia de um exercício supramáximo (120% VO2max). Foi analisada a resposta on do VO2 e também as respostas cardiorrespiratórias e metabólicas durante 20 minutos de exercício com carga constante realizados a 50 e 70% VO2max...
The appearance of an equipment that permits the oxygen consumption analysis (VO2) breath by breath has arisen a huge interest in factors which can influence its dynamics in the beginning of exercise (on response). Among the more studied factors, are the exercise intensity and training status. Meanwhile, few studies have analyzed the possible effects of previous exercise on the VO2response during exercise at moderate domain. In our lab, we have verified recently that during an incremental test performed eight minutes after a supramaximum exercise (120% VO2max), there was a significant VO2 increase in the first stage, while, at the intensities between 60% and VO2max, no alteration of VO2 was found, in accordance with the results existent in the literature. These results suggest that the influence of a previous exercise on the VO2 during the incremental exercise would just occur at low intensities (< 60% VO2 max). This model, meanwhile, does not permit to isolate a possible time effect of the exercise, once the highest intensities were always done after two or three stages, which could have favored a recovery, at least partially, of the metabolic conditions. In this way, the data until the present moment do not permit to identify if the normalization of VO2 during the incremental exercise is more dependent on the time and/or the exercise intensity. Therefore, the aims of this study were: a) to analyze the influence of the previous supramaximum exercise on the VO2 kinetics during the rest-exercise transition carried out at 50 and 70% VO2max, and b) to analyze the influence of the previous supramaximum exercise on the cardiorespiratory and metabolic responses during the constant loading exercise performed at 50 and 70% VO2max... (Complete abstract, click eletronic address below)
Chapitres de livres sur le sujet "VO2p kinetic"
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Lynch, Gordon S., David G. Harrison, Hanjoong Jo, Charles Searles, Philippe Connes, Christopher E. Kline, C. Castagna et al. « Slow Component of VO2 on-kinetics ». Dans Encyclopedia of Exercise Medicine in Health and Disease, 794–95. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-540-29807-6_3045.
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« VO2 On-Kinetics ». Dans Encyclopedia of Exercise Medicine in Health and Disease, 891. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-540-29807-6_3178.
Texte intégralActes de conférences sur le sujet "VO2p kinetic"
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Buekers, Joren, Patrick De Boever, Alberto Peña Fernández, Jan Theunis, Emiel Wouters, Martijn Spruit et Jean-Marie Aerts. « Box-Jenkins transfer function modelling for accurate determination of VO2 kinetics in COPD patients ». Dans ERS International Congress 2019 abstracts. European Respiratory Society, 2019. http://dx.doi.org/10.1183/13993003.congress-2019.pa4134.
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