Dynamic Responses of O2 Uptake at the Onset and End of Exercise in Trained Subjects

2003 ◽  
Vol 28 (4) ◽  
pp. 630-641 ◽  
Author(s):  
Christophe Cleuziou ◽  
Stéphane Perrey ◽  
Fabio Borrani ◽  
Anne Marie Lecoq ◽  
Robin Candau ◽  
...  
Keyword(s):  
Ventilatory Threshold ◽  
Slow Component ◽  
Exponential Model ◽  
Oxygen Uptake Kinetics ◽  
Dynamic Responses ◽  
Parameter Estimates ◽  
Cycling Exercise ◽  
Trained Subjects ◽  
Key Words Oxygen Uptake ◽  
Double Exponential

Inconsistencies about dynamic asymmetry between the on- and off-transient responses in [Formula: see text] are found in the literature. Therefore the purpose of this study was to examine [Formula: see text]on- and off-transients during moderate- and heavy-intensity cycling exercise in trained subjects. Ten men underwent an initial incremental test for the estimation of ventilatory threshold (VT) and, on different days, two bouts of square-wave exercise at moderate (< VT) and heavy (> VT) intensities. [Formula: see text] kinetics in exercise and recovery were better described by a single exponential model (< VT), or by a double exponential with two time delays (> VT). For moderate exercise, we found a symmetry of [Formula: see text] kinetics between the on- and off-transients (i.e., fundamental component), consistent with a system manifesting linear control dynamics. For heavy exercise, a slow component superimposed on the fundamental phase was expressed in both the exercise and recovery, with similar parameter estimates. But the on-transient values of the time constant were appreciably faster than the associated off-transient, and independent of the work rate imposed (< VT and > VT). Our results do not support a dynamically linear system model of [Formula: see text] during cycling exercise in the heavy-intensity domain. Key words: oxygen uptake kinetics, on- and off-transients, slow component

Dynamic Responses of Oxygen Uptake at the Onset and End of Moderate and Heavy Exercise in Trained Subjects

2004 ◽  
Vol 29 (1) ◽  
pp. 32-44 ◽  
Author(s):  
Christophe Cleuziou ◽  
Stéphane Perrey ◽  
Fabio Borrani ◽  
Anne Marie Lecoq ◽  
Robin Candau ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Ventilatory Threshold ◽  
Slow Component ◽  
Exponential Model ◽  
Dynamic Responses ◽  
Parameter Estimates ◽  
Heavy Exercise ◽  
Cycling Exercise ◽  
Trained Subjects ◽  
Key Words Oxygen Uptake

Inconsistencies about dynamic asymmetry between the on- and off-transient responses in [Formula: see text] are found in the literature. Therefore the purpose of this study was to examine [Formula: see text]on-and off-transients during moderate- and heavy-intensity cycling exercise in trained subjects. Ten men underwent an initial incremental test for the estimation of ventilatory threshold (VT) and, on different days, two bouts of square-wave exercise at moderate (< VT) and heavy (> VT) intensities. [Formula: see text] kinetics in exercise and recovery were better described by a single exponential model (< VT), or by a double exponential with two time delays (> VT). For moderate exercise, we found a symmetry of [Formula: see text] kinetics between the on- and off-transients (i.e., fundamental component), consistent with a system manifesting linear control dynamics. For heavy exercise, a slow component superimposed on the fundamental phase was expressed in both the exercise and recovery, with similar parameter estimates. But the on-transient values of the time constant were appreciably faster than the associated off-transient, and independent of the work rate imposed (< VT and > VT). Our results do not support a dynamically linear system model of [Formula: see text] during cycling exercise in the heavy-intensity domain. Key words: oxygen uptake kinetics, on- and off-transients, slow component

Oxygen uptake kinetics in treadmill running and cycle ergometry: a comparison

2000 ◽  
Vol 89 (3) ◽  
pp. 899-907 ◽  
Author(s):  
Helen Carter ◽  
Andrew M. Jones ◽  
Thomas J. Barstow ◽  
Mark Burnley ◽  
Craig A. Williams ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Slow Component ◽  
Maximal Oxygen Consumption ◽  
Exponential Model ◽  
Oxygen Uptake Kinetics ◽  
Treadmill Running ◽  
Tension Development ◽  
Exercise Transitions ◽  
The Difference ◽  
Power Outputs

The purpose of the present study was to comprehensively examine oxygen consumption (V˙o 2) kinetics during running and cycling through mathematical modeling of the breath-by-breath gas exchange responses to moderate and heavy exercise. After determination of the lactate threshold (LT) and maximal oxygen consumption (V˙o 2 max) in both cycling and running exercise, seven subjects (age 26.6 ± 5.1 yr) completed a series of “square-wave” rest-to-exercise transitions at running speeds and cycling power outputs that corresponded to 80% LT and 25, 50, and 75%Δ (Δ being the difference between LT andV˙o 2 max).V˙o 2 responses were fit with either a two- (<LT) or three-phase ( >LT) exponential model. The parameters of theV˙o 2 kinetic response were similar between exercise modes, except for the V˙o 2 slow component, which was significantly ( P < 0.05) greater for cycling than for running at 50 and 75%Δ (334 ± 183 and 430 ± 159 ml/min vs. 205 ± 84 and 302 ± 154 ml/min, respectively). We speculate that the differences between the modes are related to the higher intramuscular tension development in heavy cycle exercise and the higher eccentric exercise component in running. This may cause a relatively greater recruitment of the less efficient type II muscle fibers in cycling.

Cardiovascular and Oxygen Uptake Kinetics During Sequential Heavy Cycling Exercises

2003 ◽  
Vol 28 (2) ◽  
pp. 283-298 ◽  
Author(s):  
Stéphane Perrey ◽  
Jodie Scott ◽  
Laurent Mourot ◽  
Jean-Denis Rouillon
Keyword(s):  
Cardiac Output ◽  
Oxygen Uptake ◽  
Time Constant ◽  
Impedance Cardiography ◽  
Ventilatory Threshold ◽  
Slow Component ◽  
Oxygen Uptake Kinetics ◽  
Cycle Ergometer ◽  
Fast Component ◽  
Heavy Exercise

The purpose of the present study was to assess the relationship between the rapidity of increased oxygen uptake [Formula: see text] and increased cardiac output (CO) during heavy exercise. Six subjects performed repeated bouts on a cycle ergometer above the ventilatory threshold (∼80% of peak [Formula: see text]) separated by 10-min recovery cycling at 35% peak [Formula: see text]. [Formula: see text] was determined breath-by-breath and CO was determined continuously by impedance cardiography. CO and [Formula: see text] values were significantly higher during the 2-min period preceding the second bout. The overall responses for [Formula: see text] and CO were significantly related and were faster during the second bout. Prior heavy exercise resulted in a significant increase in the amplitude of the fast component of [Formula: see text] with no change in the time constant and a decrease in the slow component. Under these circumstances, the amplitude of the fast component was more sensitive to prior heavy exercise than was the associated time constant. Key words: impedance cardiography, exercise transitions, cardiac output, prior exercise

Is the VO2 slow component in heavy arm-cranking exercise associated with recruitment of type II muscle fibers as assessed by an increase in surface EMG?

2006 ◽  
Vol 31 (4) ◽  
pp. 414-422 ◽  
Author(s):  
Sylvain Bernasconi ◽  
Nicolas Tordi ◽  
Stéphane Perrey ◽  
Bernard Parratte ◽  
Guy Monnier
Keyword(s):  
Ventilatory Threshold ◽  
Biceps Brachii ◽  
Slow Component ◽  
Muscle Fibers ◽  
Exponential Model ◽  
Type Ii ◽  
Triceps Brachii ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Arm Cranking

The recruitment of additional type II muscle fibers is one mechanism often suggested to be responsible for the slow component of oxygen uptake (VO2 SC). We hypothesized that surface electromyogram (EMG) of the biceps brachii, triceps brachii, anterior deltoid, and infraspinatus muscles could be related to the VO2 SC amplitude during arm-cranking exercises above ventilatory threshold (VT). Eight healthy subjects performed transitions from rest to 6-min heavy exercise at a constant power output of approximately 40% between VT and peak VO2. A 2-component exponential model was used to fit the VO2 response. EMG were recorded the last 15 s of each minute to obtain root mean square (RMS) and mean power frequency (MPF). Mean EMG responses for RMS and MPF were calculated by averaging EMG responses of the 4 muscles. The VO2 SC amplitude was of 530 ± 166 mL/min and occurred after 134 ± 31 s of exercise onset. Significant correlations were found for most of the subjects between EMG parameters and the VO2 SC amplitude as determined between the 2nd and the 6th minute. For all muscles, RMS values significantly increased over time during the VO2 SC, whereas MPF decreased significantly. These results suggest a relation between the recruitment of additional type II muscle fibers and the VO2 SC in arm-cranking exercises.

Are Oxygen Uptake Kinetics Modified When Using a Respiratory Snorkel?

2010 ◽  
Vol 5 (3) ◽  
pp. 292-300 ◽  
Author(s):  
Joana F. Reis ◽  
Gregoire P. Millet ◽  
Davide Malatesta ◽  
Belle Roels ◽  
Fabio Borrani ◽  
...  
Keyword(s):  
Slow Component ◽  
Oxygen Uptake Kinetics ◽  
Primary Phase ◽  
Kinetics Parameters ◽  
Power Cycle ◽  
Double Exponential ◽  
Valid Instrument ◽  
Component Amplitude ◽  
Double Exponential Function

Purpose:The aim of this study was to compare VO2 kinetics during constant power cycle exercise measured using a conventional facemask (CM) or a respiratory snorkel (RS) designed for breath-by-breath analysis in swimming.Methods:VO2 kinetics parameters—obtained using CM or RS, in randomized counterbalanced order—were compared in 10 trained triathletes performing two submaximal heavy-intensity cycling square-wave transitions. These VO2 kinetics parameters (ie, time delay: td1, td2; time constant: τ1, τ2; amplitude: A1, A2, for the primary phase and slow component, respectively) were modeled using a double exponential function. In the case of the RS data, this model incorporated an individually determined snorkel delay (ISD).Results:Only td1 (8.9 ± 3.0 vs 13.8 ± 1.8 s, P < .01) differed between CM and RS, whereas all other parameters were not different (τ1 = 24.7 ± 7.6 vs 21.1 ± 6.3 s; A1 = 39.4 ± 5.3 vs 36.8 ± 5.1 mL·min−1·kg−1; td = 107.5 ± 87.4 vs 183.5 ± 75.9 s; A2' (relevant slow component amplitude) = 2.6 ± 2.4 vs 3.1 ± 2.6 mL·min−1·kg−1 for CM and RS, respectively).Conclusions:Although there can be a small mixture of breaths allowed by the volume of the snorkel in the transition to exercise, this does not appear to significantly influence the results. Therefore, given the use of an ISD, the RS is a valid instrument for the determination of VO2 kinetics within submaximal exercise.

Similar level of impairment in exercise performance and oxygen uptake kinetics in middle-aged men and women with type 2 diabetes

2012 ◽  
Vol 303 (1) ◽  
pp. R70-R76 ◽  
Author(s):  
Eamonn O'Connor ◽  
Catherine Kiely ◽  
Donal O'Shea ◽  
Simon Green ◽  
Mikel Egaña
Keyword(s):  
Type 2 Diabetes ◽  
Oxygen Uptake ◽  
Ventilatory Threshold ◽  
Constant Load ◽  
Peak Oxygen Uptake ◽  
Oxygen Uptake Kinetics ◽  
Dynamic Responses ◽  
Middle Aged ◽  
Men And Women

The present study tested the hypothesis that the magnitude of the type 2 diabetes-induced impairments in peak oxygen uptake (V̇o2) and V̇o2 kinetics would be greater in females than males in middle-aged participants. Thirty-two individuals with type 2 diabetes (16 male, 16 female), and 32 age- and body mass index (BMI)-matched healthy individuals (16 male, 16 female) were recruited. Initially, the ventilatory threshold (VT) and peak V̇o2 were determined. On a separate day, subjects completed four 6-min bouts of constant-load cycling at 80% VT for the determination of V̇o2 kinetics using standard procedures. Cardiac output (CO) (inert gas rebreathing) was recorded at rest, 30, and 240 s during two additional bouts. Peak V̇o2 (ml·kg−1·min−1) was significantly reduced in men and women with type 2 diabetes compared with their respective nondiabetic counterparts (men, 27.8 ± 4.4 vs. 31.1 ± 6.2 ml·kg−1·min−1; women, 19.4 ± 4.1 vs. 21.4 ± 2.9 ml·kg−1·min−1). The time constant (s) of phase 2 (τ2) and mean response time (s) of the V̇o2 response (MRT) were slowed in women with type 2 diabetes compared with healthy women (τ2, 43.3 ± 9.8 vs. 33.6 ± 10.0 s; MRT, 51.7 ± 9.4 vs. 43.5 ± 11.4s) and in men with type 2 diabetes compared with nondiabetic men (τ2, 43.8 ± 12.0 vs. 35.3 ± 9.5 s; MRT, 57.6 ± 8.3 vs. 47.3 ± 9.3 s). The magnitude of these impairments was not different between males and females. The steady-state CO responses or the dynamic responses of CO were not affected by type 2 diabetes among men or women. The results suggest that the type 2 diabetes-induced impairments in peak V̇o2 and V̇o2 kinetics are not affected by sex in middle aged participants.

scholarly journals VO2Kinetics and Metabolic Contributions Whilst Swimming at 95, 100, and 105% of the Velocity atVO2 max

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ana C. Sousa ◽  
João P. Vilas-Boas ◽  
Ricardo J. Fernandes
Keyword(s):  
Slow Component ◽  
Exponential Model ◽  
Metabolic Profiles ◽  
Energy Contribution ◽  
Square Wave ◽  
Double Exponential ◽  
Incremental Protocol ◽  
Double Exponential Model ◽  
And Diffusion ◽  
Energy Components

A bioenergetical analysis of swimming at intensities near competitive distances is inexistent. It was aimed to compare the transientVO2kinetics responses and metabolic contributions whilst swimming at different velocities aroundVO2max⁡. 12 trained male swimmers performed (i) an incremental protocol to determine the velocity atVO2max⁡(vVO2max⁡) and (ii) three square wave exercises from rest to 95, 100, and 105% ofvVO2max⁡.VO2was directly measured using a telemetric portable gas analyser and its kinetics analysed through a double-exponential model. Metabolic contributions were assessed through the sum of three energy components. No differences were observed in the fast component response (τ1—15, 18, and 16 s,A1—36, 34, and 37 mL·kg-1·min⁡-1, and Gain—32, 29, and 30 mL·min⁡-1at 95, 100, and 105% of thevVO2max⁡, resp.) but A2 was higher in 95 and 100% compared to 105% intensity (480.76 ± 247.01, 452.18 ± 217.04, and 147.04 ± 60.40 mL·min⁡-1, resp.). The aerobic energy contribution increased with the time sustained (83 ± 5, 74 ± 6, and 59 ± 7% for 95, 100, and 105%, resp.). The adjustment of the cardiovascular and/or pulmonary systems that determineO2delivery and diffusion to the exercising muscles did not change with changing intensity, with the exception ofVO2slow component kinetics metabolic profiles.

Linear and nonlinear characteristics of oxygen uptake kinetics during heavy exercise

1991 ◽  
Vol 71 (6) ◽  
pp. 2099-2106 ◽  
Author(s):  
T. J. Barstow ◽  
P. A. Mole
Keyword(s):  
Oxygen Uptake ◽  
Slow Component ◽  
Oxygen Uptake Kinetics ◽  
Work Rate ◽  
Phase 2 ◽  
Maximal Aerobic Capacity ◽  
Nonlinear Characteristics ◽  
Exponential Regression ◽  
Double Exponential ◽  
Mean Time

We assessed the linearity of oxygen uptake (VO2) kinetics for several work intensities in four trained cyclists. VO2 was measured breath by breath during transitions from 33 W (baseline) to work rates requiring 38, 54, 85, and 100% of maximal aerobic capacity (VO2max). Each subject repeated each work rate four times over 8 test days. In every case, three phases (phases 1, 2, and 3) of the VO2 response could be identified. VO2 during phase 2 was fit by one of two models: model 1, a double exponential where both terms begin together close to the start of phase 2, and model 2, a double exponential where each of the exponential terms begins independently with separate time delays. VO2 rose linearly for the two lower work rates (slope 11 ml.min-1 W-1) but increased to a greater asymptote for the two heavier work rates. In all four subjects, for the two lighter work rates the double-exponential regression reduced to a single value for the time constant (average across subjects 16.1 +/- 7.7 s), indicating a truly monoexponential response. In addition, one of the responses to the heaviest work rate was monoexponential. For the remaining seven biexponential responses to the two heaviest work rates, model 2 produced a significantly better fit to the responses (P less than 0.05), with a mean time delay for the slow component of 105 +/- 46 s.(ABSTRACT TRUNCATED AT 250 WORDS)

Sign in / Sign up

Export Citation Format

Share Document