Effect of prior exercise on maximal short-term power output in humans

1987 ◽  
Vol 63 (4) ◽  
pp. 1475-1480 ◽  
Author(s):  
A. J. Sargeant ◽  
P. Dolan
Keyword(s):  
Power Output ◽  
Dominant Role ◽  
Recovery Period ◽  
O2 Uptake ◽  
Short Term ◽  
Prior Exercise ◽  
Dynamic Function ◽  
In Series ◽  
Series Of Experiments ◽  
Kinetics Of

The effect of prior exercise (PE) on subsequent maximal short-term power output (STPO) was examined during cycling exercise on an isokinetic ergometer. In the first series of experiments the duration of PE at a power output equivalent to 98% maximum O2 uptake (VO2max) was varied between 0.5 and 6 min before measurement of maximal STPO. As PE duration increased subsequent STPO fell to approximately 70% of control values after 3–6 min. In series ii the effect of varying the intensity of PE of fixed 6-min duration was studied in five subjects. After PE less than 60% VO2max there was an increase of 12% in STPO, but after greater than 60% VO2max there was a progressive fall in STPO as PE intensity increased, indicating a reduction of approximately 35% at 100% VO2max compared with control values. In series iii we examined the effect on STPO of allowing a recovery period after a fixed intensity (mean = 87% VO2max) of 6 min PE before measurement of STPO. This indicated a rapid recovery of dynamic function with a half time of approximately 32 s, which is similar to the kinetics of PC resynthesis and taken with the other findings suggests the dominant role that PC exerts on the STPO under these conditions.

Model-based characterisation of hydraulic, kinetic and influent properties of an industrial WWTP

1998 ◽  
Vol 37 (12) ◽  
pp. 317-326 ◽  
Author(s):  
F. Coen ◽  
B. Petersen ◽  
P. A. Vanrolleghem ◽  
B. Vanderhaegen ◽  
M. Henze
Keyword(s):  
Industrial Wastewater ◽  
Treatment Plant ◽  
Tracer Test ◽  
Model Structure ◽  
Short Term ◽  
Loading Rates ◽  
Model Based ◽  
In Series ◽  
On Line ◽  
Kinetics Of

This paper illustrates the modelling of a full-scale industrial wastewater treatment plant. First, the hydraulics of the plant were characterised by a model-based interpretation of the results of a tracer test. The plant consists of three parallel reactors. The hydraulics of each reactor could be modelled by two tanks in series with non-equal volume. These results were confirmed by calculation of the single pass residence time distribution. Also it was found that the influent flow and the recycle flow were not distributed equally to the three reactors, resulting in different loading rates. Secondly, off-line respirometric experiments were performed to characterise the influent and to determine the sludge kinetics. The same model structure could be applied to describe the influent characteristics and the biokinetics over a period of 1 year. It was found that all wastewaters could be fractionated into three fractions and that one of the fractions was acetate-like. Concentrations of the fractions changed significantly over the year. From on-line respirometric experiments the diurnal dynamics of the influent characteristics and the kinetics of the sludge were assessed. Analysis of the respirograms showed that the wastewater composition and kinetics of the sludge did not change significantly over a short-term period of 40 hours.

Positive effect of specific low-frequency electrical stimulation during short-term recovery on subsequent high-intensity exercise

2014 ◽  
Vol 39 (2) ◽  
pp. 202-210 ◽  
Author(s):  
François Bieuzen ◽  
Rachel Borne ◽  
Jean-François Toussaint ◽  
Christophe Hausswirth
Keyword(s):  
Electrical Stimulation ◽  
Beneficial Effect ◽  
Blood Lactate ◽  
Saturation Index ◽  
Recovery Period ◽  
Low Frequency ◽  
Short Term ◽  
Kinetics Of ◽  
Calf Muscles ◽  
Recovery Methods

The objective of this study was to test how low-frequency electrical stimulation (LFES; Veinoplus Sport (AdRem Technology, Paris, France)) of the calf muscles affects recovery indices compared with 2 other commonly used recovery methods (active, ACT; passive, PAS). The tests used assessed predominantly anaerobic performance after short-term (15 min) recovery, and the kinetics of blood markers. Fourteen highly trained female handball players completed 2 Yo-Yo Intermittent Recovery tests (level 2; YYIR2) separated by a 15-min recovery period. During recovery, 1 of 3 recovery methods (ACT, LFES or PAS) was randomly selected. Performance (i.e., distance run) was measured at the end of each YYIR2 test. Blood lactate, pH, bicarbonate concentrations, heart rate, respiratory gas exchange and tissue saturation index for the lateral gastrocnemius were recorded. LFES showed a very likely beneficial effect on performance during the second YYIR2 relative to PAS and a possible beneficial effect relative to ACT (distance Pre vs. Post; LFES: –1.8%; ACT: –7.6%; PAS: –15.9%). Compared with PAS recovery, LFES and ACT recovery clearly showed a faster return to baseline for blood lactate, pH and bicarbonate concentrations during the recovery period. LFES of the calf muscles and, to a lesser extent, ACT recovery appear to effectively improve short-term recovery between 2 bouts of exhausting exercises. These methods could be of benefit if applied during half-time, for sports involving successive rounds, or where only a limited recovery period is available.

scholarly journals Evaluating the suitability of supra-POpeak verification trials after ramp-incremental exercise to confirm the attainment of maximum O2 uptake

2020 ◽  
Vol 319 (3) ◽  
pp. R315-R322
Author(s):  
Danilo Iannetta ◽  
Rafael de Almeida Azevedo ◽  
Christina P. Ingram ◽  
Daniel A. Keir ◽  
Juan M. Murias
Keyword(s):  
Power Output ◽  
Exercise Duration ◽  
Incremental Exercise ◽  
O2 Uptake ◽  
Ramp Test ◽  
In Series ◽  
Test Exercise

During exhaustive ramp-incremental cycling tests, the incidence of O2 uptake (V̇o2) plateaus is low. To verify the attainment of maximum V̇o2 (V̇o2max), it is recommended that a trial at a power output (PO) corresponding to 110% of the ramp-derived peak (POpeak) is performed. It remains unclear whether verification trials set at this PO can be tolerated for long enough to allow attainment of V̇o2max. Eleven recreationally trained individuals performed five ramp tests of varying slope (5, 10, 15, 25, and 30 W/min), each followed, in series, by two verification trials: the first at 110% POpeak of the 25 W/min ramp and the second at 110% POpeak attained in the preceding ramp test. Exercise duration of the first verification trial was on average 81 ± 15 s (CV = 9 ± 3%) versus 162 ± 32, 121 ± 24, 103 ± 15, and 73 ± 10 s for the second verification trials at 110% of POpeak of the 5, 10, 15, and 30 W/min ramp tests, respectively ( P < 0.05). Compared with the highest V̇o2 recorded during ramp tests, V̇o2 from the subsequent verification trials was not different for the 5, 10, and 15 W/min ramp tests ( P > 0.05) but was lower for the 25 and 30 W/min ramp tests ( P < 0.05). Verification trials at 110% POpeak of rapidly incrementing ramp tests (i.e., 25 W/min) were not sustained for long enough to allow the attainment of V̇o2max. With commonly used rapidly incrementing ramp tests engendering exhaustion within 8–12 min, verification trials less than POpeak should be preferred as they can be sustained sufficiently long to allow the attainment of V̇o2max.

scholarly journals Control of AMPA receptor activity by the extracellular loops of auxiliary proteins

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Irene Riva ◽  
Clarissa Eibl ◽  
Rudolf Volkmer ◽  
Anna L Carbone ◽  
Andrew JR Plested
Keyword(s):  
Ampa Receptor ◽  
Ampa Receptors ◽  
De Novo ◽  
Dominant Role ◽  
Mammalian Brain ◽  
Binding Assays ◽  
Receptor Kinetics ◽  
Receptor Complexes ◽  
Extracellular Loops ◽  
Kinetics Of

At synapses throughout the mammalian brain, AMPA receptors form complexes with auxiliary proteins, including TARPs. However, how TARPs modulate AMPA receptor gating remains poorly understood. We built structural models of TARP-AMPA receptor complexes for TARPs γ2 and γ8, combining recent structural studies and de novo structure predictions. These models, combined with peptide binding assays, provide evidence for multiple interactions between GluA2 and variable extracellular loops of TARPs. Substitutions and deletions of these loops had surprisingly rich effects on the kinetics of glutamate-activated currents, without any effect on assembly. Critically, by altering the two interacting loops of γ2 and γ8, we could entirely remove all allosteric modulation of GluA2, without affecting formation of AMPA receptor-TARP complexes. Likewise, substitutions in the linker domains of GluA2 completely removed any effect of γ2 on receptor kinetics, indicating a dominant role for this previously overlooked site proximal to the AMPA receptor channel gate.

Recovery ability of common carp (Cyprinus carpio) after a short-term exposure to terbuthylazine

2013 ◽  
Vol 16 (1) ◽  
pp. 17-23 ◽  
Author(s):  
I. Mikulikova ◽  
H. Modra ◽  
J. Blahova ◽  
K. Kruzikova´ ◽  
P. Marsalek ◽  
...  
Keyword(s):  
Cyprinus Carpio ◽  
Histopathological Examination ◽  
Recovery Period ◽  
Plasma Concentrations ◽  
Hepatosomatic Index ◽  
Short Term ◽  
Plasma Albumin ◽  
Short Term Exposure ◽  
High Regeneration ◽  
Biomarkers Of Oxidative Stress

Abstract Effects of a high terbuthylazine concentration (3.3 mg/l) on Cyprinus carpio were studied using a commercial herbicide formulation Click 500 SC (terbuthylazine 500 g/l). The fish were exposed to the pesticide for 24 h and allowed to recover for 6 days. Biometric parameters, plasma biochemical parameters and biomarkers of oxidative stress as well as histopathological changes in selected tissues were assessed on day 1 and 7. After a 24-h exposure, there were significant alterations found in the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) as well as in the plasma concentrations of glucose, natrium, chlorides, calcium and phosphorus. Hepatosomatic index, plasma albumin and lactate reflected the treatment with a delay. Ion levels and ALT were found to be restored after a 6-day recovery period, which was too short for AST activity and glucose to diminish to the control levels. The histopathological examination revealed disorders in the gills of the exposed fish, however, the changes were not detected after a 6-day recovery period. The study shows high regeneration potential of the fish.

Measurements of metabolic rate in rats: a comparison of techniques

1988 ◽  
Vol 65 (2) ◽  
pp. 964-970 ◽  
Author(s):  
T. I. Musch ◽  
A. Bruno ◽  
G. E. Bradford ◽  
A. Vayonis ◽  
R. L. Moore
Keyword(s):  
Metabolic Rate ◽  
Maximal Exercise ◽  
Ambient Air ◽  
Open Circuit ◽  
Submaximal Exercise ◽  
Co2 Production ◽  
Arterial Blood ◽  
In Series ◽  
Series Of Experiments ◽  
Four Levels

Two different open-circuit techniques of measuring metabolic rate were examined in rats at rest and during exercise. With one technique ambient air was drawn through a tightly fitting mask that was secured to the rat's head, whereas with the other technique the rat was placed into and ambient air was drawn through a Plexiglas box. Two series of experiments were performed. In series I, two groups were studied that consisted of rats that had received myocardial infarctions produced by coronary arterial ligations and rats that had received sham operations. In this series of experiments O2 uptake (VO2) and CO2 production (VCO2) were measured at rest, during four levels of submaximal exercise, and during maximal treadmill exercise in the same group of rats by use of both techniques in random order. VO2, VCO2, and the calculated respiratory exchange ratio (R) were similar at rest, during the highest level of submaximal exercise (20% grade, 37 m/min), and during maximal exercise; however, VO2 and VCO2 were significantly lower with the metabolic box technique compared with the mask technique during the three lowest work loads (5% grade, 19 m/min; 10% grade, 24 m/min; and 15% grade, 31 m/min). These differences appeared to be associated with a change in gait produced when the mask was worn. In series II, the arterial blood gas and acid-base responses to both submaximal and maximal exercise were measured using both techniques in a group of instrumented rats that had a catheter placed into the right carotid artery.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals A comparison of the short-term kinetics of zinc metabolism in women during fasting and following a breakfast meal

1998 ◽  
Vol 80 (4) ◽  
pp. 363-370 ◽  
Author(s):  
Nicola M. Lowe ◽  
Leslie R. Woodhouse ◽  
Janet C. King
Keyword(s):  
Energy Content ◽  
Compartment Model ◽  
Zinc Metabolism ◽  
Short Term ◽  
Compartment System ◽  
Breakfast Meal ◽  
Physiological Importance ◽  
Two Compartment Model ◽  
Zn Concentration ◽  
Kinetics Of

The physiological importance and mechanism of the postprandial fall in plasma Zn concentration is not well understood. In order to gain further information on this apparent redistribution of plasma Zn, a stable isotope, 70Zn, was used to study the effect of a breakfast meal on plasma Zn kinetics. Nine women participated in two trials, a fasting trial and a breakfast-meal trial; five of the women participated in a third trial in which the energy content of the breakfast meal was doubled. At each trial, 0.1mg of 70Zn was infused intravenously, and the plasma disappearance of the isotope was analysed using a two-compartment model of Zn kinetics. Plasma Zn concentration fell significantly following the two trials in which the subjects were given meals, reaching low points that were 13 and 19 %, respectively, below concentrations at comparable times during the fasting trial. Kinetic analysis revealed that after the doubled breakfast meal there was a significant fall (P < 0.007) in the size of the most rapidly turning over Zn pool (pool (a)) from 2.90 (se 0.13)mg in the fasting state to 2.47 (se 0.14) mg postprandially. The fractional turnover rate of pool (a) to other extravascular Zn pools, i.e. outside the two-compartment system, was also significantly elevated after the doubled breakfast meal (P < 0.05). These results suggest that the decline in plasma Zn concentration following a meal is due to a redistribution of Zn from the plasma to other more slowly turning over extravascular pools that may be involved in the assimilation and metabolism of fuels following food intake.

Right and left ventricular O2 uptake during hemodilution and beta-adrenergic stimulation

1993 ◽  
Vol 265 (5) ◽  
pp. H1769-H1777 ◽  
Author(s):  
G. J. Crystal ◽  
S. J. Kim ◽  
M. R. Salem
Keyword(s):  
Blood Flow ◽  
Blood Cells ◽  
Left Ventricular ◽  
Adrenergic Stimulation ◽  
O2 Uptake ◽  
Isovolemic Hemodilution ◽  
Content Difference ◽  
O2 Extraction ◽  
In Series ◽  
O2 Delivery

Myocardial O2 uptake (MVO2) and related variables were compared in right and left ventricles (RV and LV, respectively) during isovolemic hemodilution (HD) alone and combined with isoproterenol (Iso) infusion in 13 isoflurane-anesthetized open-chest dogs. Measurements of myocardial blood flow (MBF) obtained with radioactive microspheres were used to calculate MVO2. Lactate extraction (Lacext) was determined. The study consisted of two experimental series: 1) graded HD (dextran) to hematocrit (Hct) of 10% and 2) Iso (0.1 microgram.kg-1.min-1 iv) during moderate HD (Hct = 18 +/- 1%). In series 1, arteriovenous O2 content difference in both ventricles decreased in parallel with reduced arterial O2 content caused by HD, i.e., percent O2 extraction was constant; MVO2 was maintained by proportional increases in MBF. In series 2, Iso during moderate HD raised MVO2 (RV, +156%; LV, +80%). Higher MVO2 was satisfied by combination of increased MBF and O2 extraction in RV and by increased MBF alone in LV. Lacext remained consistent with adequate myocardial O2 delivery throughout study. Conclusions were that 1) both RV and LV tolerated extreme HD (Hct = 10%) because blood flow reserves were sufficient to fully compensate for reduced arterial O2 content; 2) significant cardiac reserve was evident during HD, which could be recruited Iso; and 3) because increase in MVO2 in RV caused by Iso in presence of HD was partially satisfied by increased O2 extraction, the absence of augmented O2 extraction during HD alone was not due to impaired release of O2 from diluted red blood cells.(ABSTRACT TRUNCATED AT 250 WORDS)

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