We hypothesized that the effective inhibition of nitric oxide synthase (NOS), achieved via systemic infusion of N(G)-nitro-l-arginine methyl ester (l-NAME), would reduce the gas exchange threshold (GET) and the maximal oxygen uptake (V(.)(O(2)max)) during incremental cycle exercise in man if NO is important in the regulation of muscle vasodilatation. Seven ...

Our objectives were firstly, to study the patterns of the cardiac output (Q(.)) and the arteriovenous oxygen difference [(a-nu(-))O(2)] responses to oxygen uptake (V(.)O(2)) during constant workload exercise (CWE) performed above the respiratory compensation point (RCP), and secondly, to establish the relationships between their kinetics and the time to exhaustion. ...

Geographic and interseasonal heterogeneity of pharyngeal group A streptococcal (GAS) genotypes (emm types) is poorly characterized. We evaluated emm type and subtype distribution among pediatric pharyngitis isolates obtained from 9 sites in the United States during 2000-2001 (year 1) and from 10 sites in the United States and 1 site ...

The main purpose of this study was to analyze the effects of exercise mode, training status and specificity on the oxygen uptake (V(.)O(2)) kinetics during maximal exercise performed in treadmill running and cycle ergometry. Seven runners (R), nine cyclists (C), nine triathletes (T) and eleven untrained subjects (U), performed the ...

OBJECTIVE: To examine how exercise-induced analgesia is affected by the duration and intensity of aerobic exercise. DESIGN: Repeated-measures design. SETTING: Exercise science laboratory. PARTICIPANTS: Convenience sample of 12 healthy male and female volunteers (mean age +/- standard deviation, 32+/-9 y). INTERVENTIONS: Pain ratings were assessed before and at 5 and ...

To derive a regression equation that estimates metabolic equivalent (MET) from accelerometer counts, and to define thresholds of accelerometer counts that can be used to delineate sedentary, light, moderate, and vigorous activity in adolescent girls. Seventy-four healthy 8th grade girls, age 13 - 14 yr, were recruited from urban areas ...

The purpose of the present study was to compare simultaneously vastus lateralis (VL) deoxygenation and pulmonary O(2) uptake (O(2)) kinetics during fatiguing knee extension exercise with minimal cardiac load. Eight healthy subjects realized an intermittent bilateral knee-extension exercise (3-s contraction/3-s relaxation) at 40% of maximum voluntary contraction for 10 min. ...

The aim of this experiment was to compare the efficiency of elite cyclists with that of trained and recreational cyclists. Male subjects (N = 69) performed an incremental exercise test to exhaustion on an electrically braked cycle ergometer. Cadence was maintained between 80 - 90 rpm. Energy expenditure was estimated ...

Previous studies have indicated that the (.-)VO(2) slow component is related to the recruitment of type II muscle fibres. We therefore hypothesised that an exercise and dietary regimen designed to deplete type I muscle fibres of glycogen would result in a greater contribution of type II muscle fibres to the ...

The aim of this study was to establish how ratings of perceived speech production difficulty (PSPD) during exercise of varying intensities are correlated with various physiological responses, in order to determine whether the PSPD is suitable for prescribing exercise training intensity. An incremental running test was performed to establish the ...

King penguins (Aptenodytes patagonicus) may fast for up to 30 days during their breeding period. As such extended fasting may affect the relationship between the rate of O(2) consumption (Vo(2)) and heart rate (f(H)), five male king penguins were exercised at various speeds on repeated occasions during a fasting period ...

The study was designed to evaluate how a bout of endurance training (ET) influences the endocrine response after head-down bed rest (HDBR). Eleven healthy males completed the study, which consisted of a 6-wk ET followed by 5 days of -6 degrees head-down HDBR. Treadmill exercise at 80% of pretraining maximal ...

The effects of endurance training in normoxia or in hypoxia on time to exhaustion ( T(lim)) at the work rate corresponding to peak oxygen uptake (VO(2peak)) were examined at sea level in 13 healthy subjects. Before and after training the subjects performed the following: (1) incremental exercises up to exhaustion ...

A biventricular assistance device has been implanted in a young woman for a peripartum cardiac failure. An intended weaning consisted of gradual reloading and exercise training monitored with peak oxygen consumption (VO(2)) and radionuclide-left ventricle ejection fraction. Progressive increase in peak VO(2) during partial assistance occurred more than 2 months, ...

For the evaluation of efficacy of cardiopulmonary exercise testing, we compared New York Heart Association functional class with peak oxygen consumption rate (VO(2)peak) in 31 patients with severe mitral regurgitation who underwent mitral valve repair surgery. One year later, the VO(2)peak values did not show significant improvement; however, the patients ...

Slowed pulmonary O(2) uptake (Vo(2)) kinetics in peripheral arterial disease (PAD) have been attributed to impaired limb blood flow and/or peripheral muscle metabolic abnormalities. Although PAD results from atherosclerotic occlusive disease in the arteries to the lower extremities, systemic abnormalities affecting whole body O(2) delivery or vascular function in PAD ...

This study examined the effects of progressive exercise to fatigue in normoxia (N) on muscle sarcoplasmic reticulum (SR) Ca(2+) cycling and whether alterations in SR Ca(2+) cycling are related to the blunted peak mechanical power output (PO(peak)) and peak oxygen consumption (Vo(2 peak)) observed during progressive exercise in hypoxia (H). ...

It is purported that supplementation with Cordyceps Sinensis (CordyMax Cs-4) will improve oxidative capacity and endurance performance. The intent of this investigation was to examine the effects of CordyMax Cs-4 supplementation on VO<(2peak,) ventilatory threshold, and endurance performance in endurance-trained cyclists. Twenty-two male cyclists participated in 5 weeks of supplementation ...

BACKGROUND: A cardinal feature of heart failure (HF) is the reduced peak aerobic power (VO(2peak)) secondary to alterations in cardiovascular and musculoskeletal function. Methods and results During the last decade, a number of randomized trials have examined the role that exercise training plays in attenuating the HF-mediated decline in VO(2peak) ...

The aim of this study was to evaluate the effect of a 15% increase in preferred pedal rate (PPR) on both time to exhaustion and pulmonary O(2) uptake (VO(2)) response during heavy exercise. Seven competitive cyclists underwent two constant-power tests (CPT) at a power output that theoretically requires 50% of ...

STUDY OBJECTIVE: Microalbuminuria in diabetes mellitus is a risk factor for cardiovascular disease. We hypothesized that microalbuminuria in type 2 diabetic patients is related to impaired cardiopulmonary function during exercise, and that the severity of impairment is correlated with the degree of microalbuminuria. DESIGN: Twenty of each of the following ...

OBJECTIVES: To evaluate the reliability and validity of measures taken during the Chester step test (CST) used to predict VO(2)max and prescribe subsequent exercise. METHODS: The CST was performed twice on separate days by 7 males and 6 females aged 22.4 (SD 4.6) years. Heart rate (HR), ratings of perceived ...

The purpose of this study was to investigate longitudinal changes with age in the kinetic response to cycling at heavy-intensity exercise in boys and girls. Twenty-two prepubertal children (13 male, 9 female) carried out a series of exercise tests on two test occasions with a 2-yr interval. On each test ...

Phase 2 pulmonary O(2) uptake (Vo(2(p))) kinetics are slowed with aging. To examine the effect of aging on the adaptation of Vo(2(p)) and deoxygenation of the vastus lateralis muscle at the onset of moderate-intensity constant-load cycling exercise, young (Y) (n = 6; 25 +/- 3 yr) and older (O) (n ...

During maximal exercise in humans, fatigue is preceded by reductions in systemic and skeletal muscle blood flow, O(2) delivery and uptake. Here, we examined whether the uptake of O(2) and substrates by the human brain is compromised and whether the fall in stroke volume of the heart underlying the decline ...

The objective of this study was to investigate the cellular localisation of MyoD and myogenin in human skeletal muscle fibres as well as the possible alterations in the expression of MyoD and myogenin in response to a single bout of endurance exercise at 40% and 75% of maximum oxygen uptake ...

OBJECTIVE: To test whether resting oxygen uptake (VO(2)), submaximal VO(2), and maximal VO(2) (VO(2max)) differs between obese adolescents (n = 18; BMI > 30) and a matched normal-weight control group after adjustment for differences in fat-free mass (FFM) and fat mass (FM). RESEARCH METHODS AND PROCEDURES: FFM and FM were ...

AIM: Although postexercise hypotension (PEH) has already been extensively demonstrated, the influence of exercise intensity on its magnitude and mechanisms is still controversial. METHODS: Twenty-three normotensive subjects were submitted to a control (45 minutes of rest) and 3 exercise sessions (cycle ergometer, 45 minutes at 30%, 50% and 75% of ...

The aim of this study was to characterize untrained Nandi boys (mean age 16.6 years) from a town (n = 11) and from a rural area (n = 19) in western Kenya (altitude approximately 2000 m.a.s.l.) in regard to their body dimensions, oxygen uptake and physical activity level. The town ...

Cardiopulmonary variables, particularly peak oxygen consumption (peak VO(2)) corrected for total and lean body weight, have been confirmed to predict prognosis in patients with chronic systolic heart failure (HF). Only limited data are available on the prognostic ability of maximal oxygen (O(2)) pulse, an indicator of stroke volume and arteriovenous ...

OBJECTIVES: Hemodynamic vulnerability after the Norwood procedure for hypoplastic left heart syndrome results from impaired myocardial function, and critical inefficiency of parallel circulation. Traditional management strategies have attempted to optimize circulatory efficiency by using arterial oxygen saturation (SaO(2)) as an index of pulmonary/systemic flow balance, attempting to maintain SaO(2) within ...

AIM: To examine the importance of peak .VO(2) in determining repeated-sprint ability (RSA), we recruited 20 well-trained females (10 team-sport athletes and 10 endurance-trained runners; mean SD peak .VO(2): 3.3+/-0.2 L x min(-1)) who were homogenous with respect to peak .VO(2) (mean difference = 0.05 L x min(-1)). METHODS: Tests ...

AIM: The aims of this investigation were to compare physiological characteristics between highly trained middle-distance and marathon male (n=17) and female (n=11) runners; to determine the most suitable variables to use in the gender comparison in these subjects, considering physical difference between genders; and to indicate some of the best ...

We examined the effects of menstrual cycle phase and oral contraceptive (OC) use on triglyceride mobilization during 90 min of rest and 60 min of leg ergometry exercise at 45 and 65% peak O(2) uptake (Vo(2 peak)) in eight moderately physically active, eumenorrheic women (24.8 +/- 1.2 yr). Subjects were ...

It has frequently been demonstrated that prior heavy cycling exercise facilitates pulmonary O(2) kinetics at the onset of subsequent heavy exercise. This might be due to improved muscle perfusion via acidosis-induced vasodilating effects. However, it is difficult to measure the blood flow (BF) to the working muscles (via the femoral ...

The StairMaster 4000 PT is a popular step ergometer which provides a submaximal test protocol (SM Predicted VO(2)max) for the prediction of VO(2)max (ml.kg(-1).min(-1)). The purpose of this study was to evaluate the SM Predicted VO(2)max protocol by comparing it to results from a VO(2)max treadmill test in 20 young ...

OBJECTIVE: To examine the effect of different levels of fractional inspired oxygen (FiO(2)) (15%, 21%, 50%) on peak oxygen consumption (VO(2)peak) during arm exercise in persons with spinal cord injury and in able-bodied controls. DESIGN: Case-control study. SETTING: University medical center in the Netherlands. PARTICIPANTS: Ten able-bodied controls, 6 persons ...

OBJECTIVES: Patients with cyanotic congenital heart disease are generally thought to be limited by hypoxemia. To correlate exercise tolerance to the severity of the cardiac abnormality and to further characterize dyspnea in affected patients, we examined 25 adults with uncorrected cyanotic congenital heart disease. DESIGN AND SETTING: Cohort study at ...

Several indicators are used as indices of cardiorespiratory reserve. Among them, oxygen uptake (VO(2)) at peak and ventilatory threshold (VAT) levels are the most common used. In the present study, endurance training was used to evaluate and compare the usefulness of a new index, the Oxygen Uptake Efficiency Slope (OUES) ...

Determination of fat oxidation at three different intensities in trained wheelchair athletes on the treadmill. The aim of the study was to assess the level and highest rate of fat oxidation in endurance-trained wheelchair athletes for recommendation on endurance training. Institute of Sports Medicine, Swiss Paraplegic Centre, Nottwil, Switzerland. Nine ...

This study evaluated the feasibility, safety, and findings from a protocol for exercise-bicycle ergometry in subacute-stroke survivors. Of 117 eligible candidates, 14 could not perform the test and 3 discontinued because of cardiac safety criteria. In the 100 completed tests, peak heart rate was 116 +/- 19.1 beats/min; peak VO(2) ...

The purpose of this study was to compare the effects of recovery type (active vs. passive) on the time spent at VO(2)max and above 90 % of VO(2)max during short intermittent runs (15 s) at 120 % of maximal aerobic speed. Twelve male subjects performed a graded test and intermittent ...

The respiratory gas exchange and ventilation during an incremental cycle exercise test were analysed in a group of 19 healthy, moderately fit men. Different computer algorithms were used to estimate the VO2 values where: (i) the rate of VCO(2) increase just exceeds the rate of VO(2) increase (DX, derivative crossing), ...

The interactions between exercise, vascular and metabolic plasticity, and aging have provided insight into the prevention and restoration of declining whole body and small muscle mass exercise performance known to occur with age. Metabolic and vascular adaptations to normoxic knee-extensor exercise training (1 h 3 times a week for 8 ...

We hypothesized that oxygen consumption ( VO(2)) rises incrementally in very heavy and fatiguing exercise where the slow component gain increases with higher work rates. Eight trained males completed a graded exercise test and bouts of square-wave cycle ergometry at 40% and 60% of the difference between the estimated lactate ...

The purpose of this study was to determine the reproducibility of the indirect Fick method for the measurement of mixed venous carbon dioxide partial pressure (P(v)CO(2)) and venous carbon dioxide content (C(v)CO(2)) for estimation of cardiac output (Q(c)), using the exponential rise method of carbon dioxide rebreathing, during non-steady-state treadmill ...

The volume of O(2) exchanged at the mouth during a breath (Vo(2,m)) is equal to that taken up by pulmonary capillaries (Vo(2,A)) only if lung O(2) stores are constant. The latter change if either end-expiratory lung volume (EELV), or alveolar O(2) fraction (Fa(O(2))) change. Measuring this requires breath-by-breath (BbB) measurement ...

We hypothesized that inhibition of nitric oxide synthase (NOS) by N(G)-nitro-L-arginine methyl ester (L-NAME) would alleviate the inhibition of mitochondrial oxygen uptake (Vo(2)) by nitric oxide and result in a speeding of phase II pulmonary Vo(2) kinetics at the onset of heavy-intensity exercise. Seven men performed square-wave transitions from unloaded ...

STUDY OBJECTIVES: To examine the effects of 6 weeks of exercise training above or below the lactate threshold (LT) on the slow component (SC) of pulmonary oxygen consumption (.VO(2)). DESIGN: Randomized controlled trial. SETTING: University human performance laboratory. PARTICIPANTS: Apparently healthy, untrained men (n = 18). INTERVENTIONS: Subjects were randomized ...

New strongylophorines-22 (1), -23 (2), -24 (3), and -25 (4) were isolated from the Okinawan sponge Petrosia (Strongylophora) corticata along with other known strongylophorines. The structures of these strongylophorines were determined on the basis of spectroscopic analysis and chemical conversions. Assessment was also made of the cytotoxicity of strongylophorines-1, -2, ...