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Results 801 - 850 of 1451
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Coen B - - 2001
The present study was designed in order to examine the objectivity and reliability of the individual anaerobic threshold (IAT) as well as its resistance against several interfering factors: missing exhaustion, preliminary exercise, longer step duration, and lower speed increment. 87 male and 24 female runners and triathletes were examined. They ...
Wozakowska-Kaplon Beata - - 2000
The aim of this study was to determine the value of an increase in plasma atrial natriuretic peptide (ANP) concentrations during submaximal exercise as a predictor of return of sinus rhythm (SR), and of its maintenance over a period of 6 months after cardioversion (CV) of chronic atrial fibrillation (AF). ...
Hildebrand A - - 2000
The purpose of this study was to investigate the distribution of lactate in plasma and red blood cells (RBC) in capillary blood during and after incremental exercise. We measured capillary plasma lactate and whole blood lactate of 10 subjects during incremental treadmill running and the first 20 min of recovery. ...
Collomp K - - 2000
To assess the eventual effects of acute oral salbutamol intake on performance and metabolism during submaximal exercise, nine healthy volunteers completed two cycling trials at a power corresponding to 80-85% VO2max, after either placebo (Pla) or salbutamol (Sal, 6 mg) treatment, according to a double-blind randomized protocol. Blood samples were ...
Baldari C - - 2000
BACKGROUND: The individual anaerobic threshold (IAT) is defined (18) as the highest metabolic rate where blood lactate (La) concentrations are maintained at a steady-state during prolonged exercise. Stegmann et al.'s (18) method to detect IAT, using La-performance relationship during incremental graded exercise, is based on the assumption that La is ...
Parolin M L - - 2000
During the onset of exercise in hypoxia, the increased lactate accumulation is associated with a delayed activation of pyruvate dehydrogenase (PDH; Parolin ML, Spreit LL, Hultman E, Hollidge-Horvat MG, Jones NL, and Heigenhauser GJF. Am J Physiol Endocrinol Metab 278: E522-E534, 2000). The present study investigated whether activation of PDH ...
Murakami M - - 2000
The purpose of this study was to measure O2 consumption of nonexercising skeletal muscles (VO2nonex) at rest and after aerobic exercise and to investigate the stimulant factors of O2 consumption. In experiment 1, we measured the resting metabolic rate of the finger flexor muscles in seven healthy males by 31P-magnetic ...
Baldwin J - - 2000
PURPOSE: This study examined the effect of training status and relative exercise intensity on physiological responses to endurance exercise in humans. METHODS: Seven endurance trained (TR: peak oxygen uptake [VO2peak] = 65.8 +/- 2.4 mL x kg(-1) min(-1)) and six untrained (UT: VO2peak = 46.2 +/- 1.9 mL x kg(-1) ...
Trueblood N A - - 2000
Nicotinic acid (niacin) has been shown to decrease myocyte injury. Because interventions that lower the cytosolic NADH/NAD(+) ratio improve glycolysis and limit infarct size, we hypothesized that 1) niacin, as a precursor of NAD(+), would lower the NADH/NAD(+) ratio, increase glycolysis, and limit ischemic injury and 2) these cardioprotective benefits ...
Claessen C C Department of Internal Medicine, University Hospital Gasthuisberg, Leuven, - - 2000
Endurance sports require a variety of physiological adaptations. To examine the structural and functional heart adaptations and their hemodynamic implications in triathletes. A group of 52 male triathletes was compared with a control group of 22 healthy male nonathletes. All of the subjects were given a bidimensional cardiac Doppler echocardiography ...
Lajoie C - - 2000
Changes in physiological variables during a 60-min continuous test at maximal lactate steady state (MLSS) were studied using highly conditioned cyclists (1 female and 9 males, aged 28.3 +/- 8.1 years). To determine power at MLSS, we tested at 8-min increments and interpolated the power corresponding to a blood lactate ...
Roecker K - - 2000
The so-called excess-CO2 in physical exertion results stoichiometrically directly from the quantity of protons bound in bicarbonate buffering. This situation is used in determining the ventilatory threshold (VT). However, the extent to which the degree and increase characteristics of excess-CO2 can be used as an equivalent to blood lactate concentrations ...
Ogino K - - 2000
1. We evaluated the plasma ammonia response to constant exercise at different intensities. Ten healthy male volunteers were asked to perform constant exercise for 15 min at five different intensities: 80, 90, 100, 110 and 120% of their ventilatory threshold (VT). Blood concentrations of lactate, ammonia and hypoxanthine were measured ...
Solberg E E - - 2000
OBJECTIVE: To compare the efficacy in runners of two relaxation techniques with regard to exercise reactivity and recovery after exercise. METHODS: Thirty one adult male runners were studied prospectively for six months in three groups practising either meditation (n = 11) or autogenic training (n = 11) or serving as ...
Eydoux N - - 2000
We investigated the effects of a single bout of non-exhaustive exercise (25 m x min(-1), 10% grade, for 30 min) on the initial rates of lactate uptake in rat skeletal muscle sarcolemmal vesicles and the monocarboxylate transporter 1 (MCT1) content in isolated hindlimb muscles in relation to the exercise-induced oxidative ...
Martin L - - 2000
The purpose of this study was to determine whether the critical swimming velocity (Vcrit) corresponds to the velocity at lactate threshold (V-LT) in elite triathletes. Eight elite triathletes (5 male, 3 female; age 26 +/- 4 years; height 1.7 +/- 0.1 m and body mass 75 +/- 4 kg) participated ...
Eydoux N - - 2000
The effects of endurance training on lactate transport capacity remain controversial. This study examined whether endurance training 1) alters lactate transport capacity, 2) can protect against exhaustive exercise-induced lactate transport alteration, and 3) can modify heart and oxidative muscle monocarboxylate transporter 1 (MCT1) content. Forty male Wistar rats were divided ...
Beneke R - - 2000
PURPOSE: The maximal lactate steady state (MLSS) corresponds to the highest workload that can be maintained over time without a continual blood lactate accumulation. MLSS and MLSS intensity have been speculated to depend on performance. Experimental proof of this hypothesis is missing. METHODS: 33 male subjects (age: 23.7 +/- 5.5 ...
Bishop D - - 2000
PURPOSE: In a previous study, we showed that when six different plasma lactate parameters (LPs) were compared, the LP determined by the Dmax method was the best predictor of 1-h cycling performance in women. The present study extended these findings to determine whether or not the relationship between the following ...
Yuan Y - - 2000
This article summarizes previous studies on blood ammonia levels in relation to exercise. The dynamics of blood ammonia were reviewed with consideration to its production, removal, and distribution in various tissue compartments. During intense exercise, the primary source of ammonia is adenosine monophosphate deamination. Catabolism of branched-chain amino acids becomes ...
Lucía A - - 2000
The aim of this longitudinal study was to analyze the changes in several metabolic and neuromuscular variables in response to endurance training during three defined periods of a full sports season (rest, precompetition and competition). The study population was formed by thirteen professional cyclists (age +/- SEM: 24+/-1 years; mean ...
Gao L - - 2000
Promotion of uptake of essential metabolites is a possible reason for the general stimulation of gonococcal metabolism which is caused by lactate (1 mM) in a defined medium containing glucose (5 mM). However, although uptake of(14)C adenine by gonococci [strain BS4(agar)] held for 4 or 7 min at 37 degrees ...
Davie A L - - 2000
The associations between velocity during a standardized, submaximal 800-m exercise test and blood lactate concentration after exercise were investigated in Thoroughbred racehorses on sand and grass racetracks. Predicted lactate concentrations for each horse's exercise test velocity were calculated from the line of best fit derived from results at each racetrack. ...
Oyono-Enguéllé S - - 2000
PURPOSE: Relative to healthy control individuals with normal hemoglobin (Hb), patients carrying the double heterozygous form of sickle cell disease (HbSC) display an impaired oxygen transport capacity. The present study was undertaken to determine the influence of the decreased oxygen availability associated with the presence of HbSC on the cardiorespiratory ...
Dubouchaud H - - 2000
To evaluate the effects of endurance training on the expression of monocarboxylate transporters (MCT) in human vastus lateralis muscle, we compared the amounts of MCT1 and MCT4 in total muscle preparations (MU) and sarcolemma-enriched (SL) and mitochondria-enriched (MI) fractions before and after training. To determine if changes in muscle lactate ...
Spriet L L - - 2000
This paper examines the production of lactate in human skeletal muscle over a range of power outputs (35-250% VO2max) from an enzymatic flux point of view. The conversion of pyruvate and NADH to lactate and NAD in the cytoplasm of muscle cells is catalyzed by the near-equilibrium enzyme lactate dehydrogenase ...
Brooks G A - - 2000
The "lactate shuttle hypothesis" holds that lactate plays a key role in the distribution of carbohydrate potential energy that occurs among various tissue and cellular compartments such as between: cytosol and mitochondria, muscle and blood, blood and muscle, active and inactive muscles, white and red muscles, blood and heart, arterial ...
Linossier M T - - 2000
The hyperoxia-improved tolerance to maximal aerobic performance was studied in relation to exercising muscle metabolic state. Five students were submitted to four different tests on a cycle ergometer, each being conducted under normoxia and hyperoxia (60% FiO2) on separate days: Test 1, a progressive exercise until exhaustion to determine the ...
Carter H - - 2000
The aim of this study was to assess the responses of blood lactate and pyruvate during the lactate minimum speed test. Ten participants (5 males, 5 females; mean +/- s: age 27.1+/-6.7 years, VO2max 52.0+/-7.9 ml x kg(-1) x min(-1)) completed: (1) the lactate minimum speed test, which involved supramaximal ...
Moquin A - - 2000
PURPOSE: The purpose of this investigation was to examine the effects of dehydration on the lactate threshold and performance time to exhaustion in women. METHODS: Seven moderately trained women (age = 23.6 +/- 1.6 yr) performed two graded exercise tests on separate occasions, once in a normally hydrated state (HY) ...
Petibois C - - 2000
This study is the first to assess the analytic potential of Fourier-transform infrared (FT-IR) spectroscopy in determining exercise-induced metabolic changes, such as glucose and lactate serum concentrations, with single 50 microL blood microsamples. One-hundred ninety-eight capillary blood samples were taken at rest (rest serum) and after rowing exercises at different ...
Forsyth J J - - 2000
OBJECTIVE: To examine the validity of using blood taken from the toe for the assessment of plasma lactate concentration in rowers. To achieve this, values were compared with those taken from the fingertip and earlobe. METHODS: Nine subjects exercised at two separate submaximum workloads on the Concept II rowing ergometer. ...
Kronfeld D S - - 2000
OBJECTIVE: To determine lactate breakpoint of horses and test for effects of training and dietary supplementation with corn oil on that breakpoint. ANIMALS: 7 healthy Arabian horses. PROCEDURES: Horses received a control diet (n = 4) or a diet supplemented with 10% corn oil (4). A training program, which comprised ...
Medbø J I - - 2000
After intense exercise muscle may give off hydrogen ions independently of lactate, perhaps by a mechanism involving sodium ions. To examine this possibility further five healthy young men cycled for 2 min to exhaustion. Blood was drawn from catheters in the femoral artery and vein during exercise and at 1-h ...
Petersen S R - - 2000
This study evaluated the effects of hyperoxia (inspired oxygen fraction = 40%) on performance during a simulated firefighting work circuit (SFWC) consisting of five events. On separate days, 17 subjects completed at least three orientation trials followed by two experimental trials while breathing either normoxic (NOX) and hyperoxic (HOX) gas ...
Prioux J - - 2000
We investigated the effects of age on breathing pattern, mouth occlusion pressure, the ratio of mouth occlusion pressure to mean inspiratory flow, and venous blood lactate kinetics during incremental exercise. Mouth occlusion pressure was used as an index of inspiratory neuromuscular activity, and its ratio to mean inspiratory flow was ...
Finsterer J - - 2000
Since there are only few data available about the lactate stress test in a group of patients with mitochondrial myopathy, we investigated the sensitivity of this test in a larger cohort of such patients. Serum lactate was determined before, during and after a 15 minute, constant 30 W workload on ...
Samelis J - - 2000
Strains of the Lactobacillus sakei/curvatus group, mainly non-slime-producing Lact. sakei, dominated the microbial flora of industrially manufactured taverna sausage, a traditional Greek cooked meat, stored at 4 degrees C and 10 degrees C in air, vacuum and 100% CO2. Atypical, arginine-positive and melibiose-negative strains of this group were isolated. The ...
Siciliano G G Department of Neurosciences, University of Pisa, Italy. - - 2000
The aim of this study was to evaluate the effects of an aerobic training program on the metabolic and sympathetic responses to exercise in 12 patients with mitochondrial myopathies. A 10-week course of aerobic training, consisting of supervised exercise every other day on an electrically braked pedal-rate bicycle ergometer was ...
Feliu J - - 1999
Blood lactate concentrations in capillary samples obtained from the ear lobe or from the finger tip are used indistinctly, since they are considered equivalents. The aim of the study reported in this paper was to verify whether that assumption is valid due to the practical implications which any possible differences ...
Chicharro J L - - 1999
Twelve trained young males (age: 24 +/- 5 years) performed an incremental test to exhaustion during which capillary blood and saliva samples were obtained to determine the blood lactate (LT) and salivary amylase (T(sa)) thresholds. The root mean-square voltage of electromyographic activity (rms-EMG) of the vastus lateralis muscle was also ...
Carter H - - 1999
The aim of this study was to assess the sensitivity of the lactate minimum speed test to changes in endurance fitness resulting from a 6 week training intervention. Sixteen participants (mean +/- s: age 23+/-4 years; body mass 69.7+/-9.1 kg) completed 6 weeks of endurance training. Another eight participants (age ...
Bacon L - - 1999
BACKGROUND: Maximum lactate steady state (MLSS) is defined as the highest steady state exercise level one can maintain while also maintaining an equilibrium between the elimination of blood lactate and the diffusion of lactate into the blood. MLSS is an excellent tool for assessing fitness level, predicting endurance performance, and ...
Bergman B C - - 1999
We evaluated the hypotheses that endurance training decreases arterial lactate concentration ([lactate](a)) during continuous exercise by decreasing net lactate release () and appearance rates (R(a)) and increasing metabolic clearance rate (MCR). Measurements were made at two intensities before [45 and 65% peak O(2) consumption (VO(2 peak))] and after training [65% ...
Ide K - - 1999
We studied cerebral oxygenation and metabolism during submaximal cycling in 12 subjects. At two work rates, middle cerebral artery blood velocity increased from 62 +/- 3 to 63 +/- 3 and 70 +/- 5 cm/s as did cerebral oxygenation determined by near-infrared spectroscopy. Oxyhemoglobin increased by 10 +/- 3 and ...
Yges C - - 1999
BACKGROUND: Although in the last few years it has been possible to determine blood ammonia, its application in coaching practice has not yet been fully established. This study was designed to evaluate the blood ammonia response to a laboratory incremental exercise test and three steady-state field tests. METHODS: There were ...
MacLean D A - - 1999
The purpose of the present study was to use the microdialysis technique to determine skeletal muscle interstitial glucose and lactate concentrations during dynamic incremental exercise in humans. Microdialysis probes were inserted into the vastus lateralis muscle, and subjects performed knee extensor exercise at workloads of 10, 20, 30, 40, and ...
Foster C - - 1999
INTRODUCTION: We have previously hypothesized restricted muscle blood flow during speed skating, secondary to the high intramuscular forces intrinsic to the unique posture assumed by speed skaters and to the prolonged duty cycle of the skating stroke. METHODS: To test this hypothesis, we studied speed skaters (N = 10) during ...
Siciliano G G Department of Neurosciences, Neurological Clinics, University of Pisa, Italy. - - 1999
Sympathetic system activation is considered one of the main factors influencing lactate production during exercise in normal individuals. In order to assess the role of such activation in mitochondrial myopathies, we compared blood catecholamine levels to those of lactate during an intermittent exercise performed at workloads near anaerobic lactate threshold. ...
Christmass M A - - 1999
The purpose of this study was to compare rates of substrate oxidation in two protocols of intermittent exercise, with identical treadmill speed and total work duration, to reduce the effect of differences in factors such as muscle fibre type activation, hormonal responses, muscle glucose uptake and non-esterified fatty acid (NEFA) ...
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