The effect of prior heavy exercise on the parameters of the power-duration curve for cycle ergometry

2009 ◽  
Vol 34 (6) ◽  
pp. 1001-1007 ◽  
Author(s):  
Akira Miura ◽  
Chiaki Shiragiku ◽  
Yuiko Hirotoshi ◽  
Asami Kitano ◽  
Masako Yamaoka Endo ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
High Intensity ◽  
Peak Oxygen Uptake ◽  
Bicycle Ergometer ◽  
Cycle Ergometry ◽  
Work Rate ◽  
Hyperbolic Function ◽  
Heavy Exercise ◽  
Improved Performance ◽  
Lactate Levels

The tolerable duration (t) of high-intensity cycle ergometry is well characterized by a hyperbolic function of power output (P) with an asymptote (termed the critical power (CP)) and a curvature constant (denoted W′). The purpose of this study was to investigate the effect of prior heavy exercise (W-up) that specifically engenders an acidosis on CP and W′. Eight healthy subjects performed 2 sets of 4 high-intensity square-wave exercise bouts on a bicycle ergometer to estimate CP and W′, with (W-up) and without (control) prior exercise, respectively. Exercise intensities of the 4 main bouts were selected in the range of 90% to 135% peak oxygen uptake so as to reach the limit of tolerance between approximately 1.5 and 10 min. The W-up bout was preceded by 6 min cycling at a work rate halfway between the lactate threshold and peak oxygen uptake (mean ± SD of 153.8 ± 29.8 W) starting 12 min before the main bout. Blood lactate levels ([La]b) just before the main exercise bouts in W-up conditions were significantly higher than those of the control (4.7 ± 1.1 and 1.4 ± 0.4 mEq·L–1, respectively; p < 0.05). However, there were no significant differences in end-exercise [La]b. W-up increased significantly the tolerable duration at every work rate compared with the control, which was attributable exclusively to increased CP (176.5 ± 34.3 and 168.7 ± 31.3 W, respectively; p < 0.05), without any significant change in W′ (11.0 ± 3.2 and 11.0 ± 3.1 kJ, respectively). It is concluded that the prior heavy exercise improved performance mainly because of an enhanced aerobic component of exercise energetics, as indicated by a higher CP and lower increment in the [La]b.

Oxygen uptake, acid-base status, and performance with varied inspired oxygen fractions

1980 ◽  
Vol 49 (5) ◽  
pp. 863-868 ◽  
Author(s):  
R. P. Adams ◽  
H. G. Welch
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Bicycle Ergometer ◽  
Carbon Dioxide Tension ◽  
Limiting Factor ◽  
Vo2 Max ◽  
And Performance ◽  
Lactate Levels ◽  
Performance Times ◽  
Inspired Oxygen

Six subjects rode a bicycle ergometer on three occasions breathing 17, 21, or 60% oxygen. In addition to rest and recovery periods, each subject worked for 10 min at 55% of maximal oxygen uptake (VO2 max) and then to exhaustion at approximately 90% VO2 max. Performance time, inspired and expired gas fractions, ventilation, and arterialized venous oxygen tension (PO2), carbon dioxide tension (PCO2), lactate, and pH were measured. VO2, carbon dioxide output, [H+]a, and [HCO3-]a were calculated. Performance times were longer in hyperoxia than in normoxia or hypoxia. However, VO2 was not different at exhaustion in normoxia compared with hypoxia or hyperoxia. During exercise, hypoxia was associated with increased lactate levels and decreased [H+]a, PCO2, and [HCO3-]a. The opposite trends were generally associated with hyperoxia. At exhaustion, [H+]a was not different under any inspired oxygen fraction. These results support the contention that oxygen is not limiting for exercise of this intensity and duration. The results also suggest that [H+] is a possible limiting factor and that the effect of oxygen on performance is perhaps related to control of [H+].

Kinetics of oxygen uptake at the onset of exercise near or above peak oxygen uptake

2000 ◽  
Vol 88 (5) ◽  
pp. 1812-1819 ◽  
Author(s):  
R. L. Hughson ◽  
D. D. O'Leary ◽  
A. C. Betik ◽  
H. Hebestreit
Keyword(s):  
Oxygen Uptake ◽  
Cardiovascular System ◽  
Time Constant ◽  
Exponential Model ◽  
Peak Oxygen Uptake ◽  
Phase 2 ◽  
Heavy Exercise ◽  
The Difference ◽  
Kinetics Of ◽  
Model Phase

We tested the hypothesis that kinetics of O2 uptake (V˙o 2) measured in the transition to exercise near or above peakV˙o 2(V˙o 2 peak) would be slower than those for subventilatory threshold exercise. Eight healthy young men exercised at ∼57, ∼96, and ∼125%V˙o 2 peak. Data were fit by a two- or three-component exponential model and with a semilogarithmic transformation that tested the difference between required V˙o 2 and measuredV˙o 2. With the exponential model, phase 2 kinetics appeared to be faster at 125% V˙o 2 peak[time constant (τ2) = 16.3 ± 8.8 (SE) s] than at 57%V˙o 2 peak(τ2 = 29.4 ± 4.0 s) but were not different from that at 96%V˙o 2 peakexercise (τ2 = 22.1 ± 2.1 s).V˙o 2 at the completion of phase 2 was 77 and 80%V˙o 2 peak in tests predicted to require 96 and 125%V˙o 2 peak. WhenV˙o 2 kinetics were calculated with the semilogarithmic model, the estimated τ2 at 96%V˙o 2 peak (49.7 ± 5.1 s) and 125%V˙o 2 peak (40.2 ± 5.1 s) were slower than with the exponential model. These results are consistent with our hypothesis and with a model in which the cardiovascular system is compromised during very heavy exercise.

Influence of exercise intensity on pulmonary oxygen uptake kinetics at the onset of exercise and recovery in male adolescents

2008 ◽  
Vol 33 (1) ◽  
pp. 107-117 ◽  
Author(s):  
Nicola Lai ◽  
Melita M. Nasca ◽  
Marco A. Silva ◽  
Fatima T. Silva ◽  
Brian J. Whipp ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Slow Component ◽  
Work Rate ◽  
Moderate Intensity ◽  
Heavy Exercise ◽  
Pulmonary Oxygen Uptake ◽  
Square Wave ◽  
Male Adolescents ◽  
Double Exponential ◽  
Single Exponential

The dynamics of the pulmonary oxygen uptake (VO2) responses to square-wave changes in work rate can provide insight into bioenergetic processes sustaining and limiting exercise performance. The dynamic responses at the onset of exercise and during recovery have been investigated systematically and are well characterized at all intensities in adults; however, they have not been investigated completely in adolescents. We investigated whether adolescents display a slow component in their VO2 on- and off-kinetic responses to heavy- and very heavy-intensity exercise, as demonstrated in adults. Healthy African American male adolescents (n = 9, 14–17 years old) performed square-wave transitions on a cycle ergometer (from and to a baseline work rate of 20 W) to work rates of moderate (M), heavy (H), and very heavy (VH) intensity. In all subjects, the VO2 on-kinetics were best described with a single exponential at moderate intensity (τ1, on = 36 ± 11 s) and a double exponential at heavy (τ1, on = 29 ± 9 s; τ2, on = 197 ± 92 s) and very heavy (τ1, on = 36 ± 9 s; τ2, on = 302 ± 14 s) intensities. In contrast, the VO2 off-kinetics were best described with a single exponential at moderate (τ1, off = 48 ± 9 s) and heavy (τ1, off = 53 ± 7 s) intensities and a double exponential at very heavy (τ1, off = 51 ± 3 s; τ2, off = 471 ± 54 s) intensity. In summary, adolescents consistently displayed a slow component during heavy exercise (on- but not off- transition) and very heavy exercise (on- and off-transitions). Although the overall response dynamics in adolescents were similar to those previously observed in adults, their specific characterizations were different, particularly the lack of symmetry between the on- and off-responses.

Acute effects of an arginine-based supplement on neuromuscular, ventilatory, and metabolic fatigue thresholds during cycle ergometry

2015 ◽  
Vol 40 (4) ◽  
pp. 379-385 ◽  
Author(s):  
Roksana B. Zak ◽  
Clayton L. Camic ◽  
Ethan C. Hill ◽  
Molly M. Monaghan ◽  
Attila J. Kovacs ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Ventilatory Threshold ◽  
Grape Seed ◽  
Peak Oxygen Uptake ◽  
Cycle Ergometer ◽  
Cycle Ergometry ◽  
Fatigue Threshold ◽  
Incremental Test ◽  
Paired Samples ◽  
Mean Differences

The purpose of the present study was to examine the effects of an acute dose of an arginine-based supplement on the physical working capacity at the fatigue threshold (PWCFT), lactate threshold (LT), ventilatory threshold (VT), and peak oxygen uptake during incremental cycle ergometry. This study used a double-blinded, placebo-controlled, within-subjects crossover design. Nineteen untrained men (mean age ± SD = 22.0 ± 1.7 years) were randomly assigned to ingest either the supplement (3.0 g of arginine, 300 mg of grape seed extract, and 300 mg of polyethylene glycol) or placebo (microcrystalline cellulose) and performed an incremental test on a cycle ergometer for determination of PWCFT, LT, VT, and peak oxygen uptake. Following a 1-week period, the subjects returned to the laboratory and ingested the opposite substance (either supplement or placebo) prior to completing another incremental test to be reassessed for PWCFT, LT, VT, and peak oxygen uptake. The paired-samples t tests indicated there were significant (P < 0.05) mean differences between the arginine and placebo conditions for the PWCFT (192 ± 42 vs. 168 ± 53 W, respectively) and VT (2546 ± 313 vs. 2452 ± 342 mL·min−1), but not the LT (135 ± 26 vs. 138 ± 22 W), absolute peak oxygen uptake (3663 ± 445 vs. 3645 ± 438 mL·min−1), or relative peak oxygen uptake (46.5 ± 6.0 vs. 46.2 ± 5.0 mL·kg−1·min−1). These findings suggested that the arginine-based supplement may be used on an acute basis for delaying the onset of neuromuscular fatigue (i.e., PWCFT) and improving the VT in untrained individuals.

scholarly journals Peak oxygen uptake reference values for cycle ergometry for the healthy Dutch population: data from the LowLands Fitness Registry

2019 ◽  
Vol 5 (2) ◽  
pp. 00056-2018 ◽  
Author(s):  
Caspar Frederik Mylius ◽  
Wilhelmus Petrus Krijnen ◽  
Cornelis Peter van der Schans ◽  
Tim Takken
Keyword(s):  
Oxygen Uptake ◽  
Regression Model ◽  
Reference Values ◽  
Cross Validation ◽  
Peak Oxygen Uptake ◽  
Cycle Ergometry ◽  
Additive Models ◽  
Dutch Population ◽  
Age Related ◽  
Best Fitting

Peak oxygen uptake (V′O2peak) is recognised as the best expression of aerobic fitness. Therefore, it is essential that V′O2peak reference values are accurate for interpreting a cardiopulmonary exercise test (CPET). These values are country specific and influenced by underlying biological ageing processes. They are normally stratified per paediatric and adult population, resulting in a discontinuity at the transition point between prediction equations. There are currently no age-related reference values available for the lifespan of individuals in the Dutch population. The aim of this study is to determine the best-fitting regression model for V′O2peak in the healthy Dutch paediatric and adult populations in relation to age.In this retrospective study, CPET cycle ergometry results of 4477 subjects without reported somatic diseases were included (907 females, age 7.9–65.0 years). Generalised additive models were employed to determine the best-fitting regression model. Cross-validation was performed against an independent dataset consisting of 3518 subjects (170 females, age 6.8–59.0 years).An additive model was the best fitting with the largest predictive accuracy in both the primary (adjusted R2=0.57, standard error of the estimate (see)=556.50 mL·min−1) and cross-validation (adjusted R2=0.57, see=473.15 mL·min−1) dataset.This study provides a robust additive regression model for V′O2peak in the Dutch population.

Vascular and metabolic response to cycle exercise in sedentary humans: effect of age

2003 ◽  
Vol 284 (4) ◽  
pp. H1251-H1259 ◽  
Author(s):  
J. G. Poole ◽  
L. Lawrenson ◽  
J. Kim ◽  
C. Brown ◽  
R. S. Richardson
Keyword(s):  
Metabolic Response ◽  
Cycle Ergometry ◽  
Work Rate ◽  
Heavy Exercise ◽  
Cycle Exercise ◽  
Arterial Blood ◽  
Young Subjects ◽  
Effect Of Age ◽  
Maximal Effort ◽  
Sedentary Subjects

We measured leg blood flow (LBF), drew arterial-venous (A-V) blood samples, and calculated muscle O2 consumption (V˙o 2) during incremental cycle ergometry exercise [15, 30, and 99 W and maximal effort (maximal work rate, WRmax)] in nine sedentary young (20 ± 1 yr) and nine sedentary old (70 ± 2 yr) males. LBF was preserved in the old subjects at 15 and 30 W. However, at 99 W and at WRmax, leg vascular conductance was attenuated because of a reduced LBF (young: 4.1 ± 0.2 l/min and old: 3.1 ± 0.3 l/min) and an elevated mean arterial blood pressure (young: 112 ± 3 mmHg and old: 132 ± 3 mmHg) in the old subjects. Leg A-V O2 difference changed little with increasing WR in the old group but was elevated compared with the young subjects. Muscle maximal V˙o 2 and cycle WRmax were significantly lower in the old subjects (young: 0.8 ± 0.05 l/min and 193 ± 7 W; old: 0.5 ± 0.03 l/min and 117 ± 10 W). The submaximally unchanged and maximally reduced cardiac output associated with aging coupled with its potential maldistiribution are candidates for the limited LBF during moderate to heavy exercise in older sedentary subjects.

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