Effect of Endurance Training on the &OV0312;O2???Work Rate Relationship in Normoxia and Hypoxia

A two-test protocol (incremental/ramp (IWT) + supramaximal constant-load (CWR)) to affirm max and obviate reliance on secondary criteria has only been validated in highly fit children. In girls (n = 15) and boys (n = 12) with a wide range of VO2max (17–47 ml/kg/min), we hypothesized that this procedure would evince a VO2-WR plateau and unambiguous VO2max even in the presence of expiratory flow limitation (EFL). A plateau in the VO2-work rate relationship occurred in 75% of subjects irrespective of EFL There was a range in RER at max exercise for girls (0.97–1.14; mean 1.06 ± 0.04) and boys (0.98−1.09; mean 1.03 ± 0.03) such that 3/15 girls and 2/12 boys did not achieve the criterion RER. Moreover, in girls with RER > 1.0 it would have been possible to achieve this criterion at 78% VO2max. Boys achieved 92% VO2max at RER = 1.0. This was true also for HRmax where 8/15 girls’ and 6/12 boys’ VO2max would have been rejected based on HRmax being < 90% of age-predicted HRmax. In those who achieved the HRmax criterion, it represented a VO2 of 86% (girls) and 87% (boys) VO2max. We conclude that this two-test protocol confirms VO2max in children across a threefold range of VO2max irrespective of EFL and circumvents reliance on secondary criteria.

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Anaerobic threshold alterations caused by endurance training in middle-aged men

Journal of Applied Physiology ◽

10.1152/jappl.1979.46.6.1039 ◽

1979 ◽

Vol 46 (6) ◽

pp. 1039-1046 ◽

Cited By ~ 255

Author(s):

J. A. Davis ◽

M. H. Frank ◽

B. J. Whipp ◽

K. Wasserman

Keyword(s):

Endurance Training ◽

Anaerobic Threshold ◽

Minute Ventilation ◽

Correlation Coefficients ◽

Cycle Ergometer ◽

Work Rate ◽

Middle Aged ◽

Co2 Output ◽

Before And After ◽

Cycle Endurance

Nine previously sedentary middle-aged males underwent cycle endurance training 45 min/day for 9 wk with an average attendance of 4.1 days/wk. Seven males served as controls. Before and after the training period, the subjects performed three cycle ergometer tests. Work rate was incremented by 15 W/min, to the limit of the subjects' tolerance, in the first two tests; the third test consisted of contant-load cycling at an O2 uptake (VO2) just below the pretraining anaerobic threshold (AT). After training, the AT increased significantly by 44%, expressed as absolute VO2, and by 15%, expressed relative to VO2 max. Significant increases were also noted in VO2max (25%), maximal minute ventilation (19%), and maximal work rate (28%). The test-retest correlation coefficients for the AT (%VO2max) were 0.91, pre- and posttraining. Training did not alter steady-state VO2 during the submaximal exercise test whereas significant decreases occurred in CO2 output, VE, respiratory quotient, and VE/VO2. No changes occurred in the control subjects during this period. These results demonstrate that the AT is profoundly influenced by endurance training in previously sedentary middle-aged males.

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Seasonal Variation of V˙O2max and the V˙O2-Work Rate Relationship in Elite Alpine Skiers

Medicine & Science in Sports & Exercise ◽

10.1249/mss.0b013e3181a8c37a ◽

2009 ◽

Vol 41 (11) ◽

pp. 2084-2089 ◽

Cited By ~ 9

Author(s):

MICAH A. GROSS ◽

FABIO A. BREIL ◽

ANDREA D. LEHMANN ◽

HANS HOPPELER ◽

MICHAEL VOGT

Keyword(s):

Seasonal Variation ◽

Work Rate ◽

Rate Relationship ◽

Alpine Skiers

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Does True Inter-Individual Variability Exist in Individual Responses After Endurance Training?

Inquiry@Queen's Undergraduate Research Conference Proceedings ◽

10.24908/iqurcp.10458 ◽

2018 ◽

Author(s):

Simo Lu

Keyword(s):

Individual Differences ◽

Measurement Error ◽

Endurance Training ◽

Training Group ◽

Individual Variability ◽

Work Rate ◽

Control Group ◽

Random Measurement Error ◽

Random Measurement ◽

The Impact

Introduction: Despite the apparent existence of individual responses, it remains unknown whether the variability observed in peak oxygen consumption (VO2peak) and work rate at onset of blood lactate (OBLAWR) response following exercise training reflects true inter-individual differences. To date, few studies include a non-exercise control group to determine the impact of random/measurement error on the variability associated with VO2peak and OBLAWR responses to endurance training. Therefore, the purpose of this study was to determine whether true individual differences exist in responses to training by assessing whether the variability in VO2peak and OBLAWR responses following training exceeded the variability in a non-training control group. Methods: 16 recreationally active males completed two incremental ramp tests to determine VO2peak and OBLAWR. Participants were assigned into the control group (n = 7) or the training group (n = 9; endurance training: 30 minutes of 65% of work rate at VO2peak, four times per week) in a manner to counterbalance baseline VO2peak measures. Results: VO2peak increased significantly (p < 0.05) (+338 ± 416.2 mL/min/kg) and OBLAWR (+32.1 ± 29.2 W) increased following endurance training. The SD in change scores was greater in the training group for VO2peak and OBLAWR than the parallel control group. Specifically, this resulted in large and moderately-large effect sizes at respective values of 0.6 for VO2peak and 0.5 for OBLAWR. Conclusion: Although these preliminary results may suggest that the variability in VO2peak and OBLAWR responses to endurance training reflect true inter-individual variability beyond random/measurement error, a definitive conclusion can be made upon the completion of the study.

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Lack of functional effects of neuromuscular electrical stimulation on skeletal muscle oxidative metabolism in healthy humans

Journal of Applied Physiology ◽

10.1152/japplphysiol.01627.2011 ◽

2012 ◽

Vol 113 (7) ◽

pp. 1101-1109 ◽

Cited By ~ 11

Author(s):

Simone Porcelli ◽

Mauro Marzorati ◽

Lorenzo Pugliese ◽

Saverio Adamo ◽

Julien Gondin ◽

...

Keyword(s):

Skeletal Muscle ◽

Electrical Stimulation ◽

Oxidative Metabolism ◽

Near Infrared ◽

Neuromuscular Electrical Stimulation ◽

Work Rate ◽

Functional Evaluation ◽

Rate Relationship

A recent study has demonstrated that neuromuscular electrical stimulation (NMES) determines, in vitro, a fast-to-slow shift in the metabolic profile of muscle fibers. The aim of the present study was to evaluate if, in the same subjects, these changes would translate, in vivo, into an enhanced skeletal muscle oxidative metabolism. Seven young men were tested (cycle ergometer) during incremental exercises up to voluntary exhaustion and moderate and heavy constant-load exercises (CLE). Measurements were carried out before and after an 8-wk training program by isometric bilateral NMES (quadriceps muscles), which induced an ∼25% increase in maximal isometric force. Breath-by-breath pulmonary O2 uptake (V̇o2) and vastus lateralis oxygenation indexes (by near-infrared spectroscopy) were determined. Skeletal muscle fractional O2 extraction was estimated by near-infrared spectroscopy on the basis of changes in concentration of deoxygenated hemoglobin + myoglobin. Values obtained at exhaustion were considered “peak” values. The following functional evaluation variables were unaffected by NMES: peak V̇o2; gas exchange threshold; the V̇o2 vs. work rate relationship (O2 cost of cycling); changes in concentration of deoxygenated hemoglobin + myoglobin vs. work rate relationship (related to the matching between O2 delivery and V̇o2); peak fractional O2 extraction; V̇o2 kinetics (during moderate and heavy CLE) and the amplitude of its slow component (during heavy CLE). Thus NMES did not affect several variables of functional evaluation of skeletal muscle oxidative metabolism. Muscle hypertrophy induced by NMES could impair peripheral O2 diffusion, possibly counterbalancing, in vivo, the fast-to-slow phenotypic changes that were observed in vitro, in a previous work, in the same subjects of the present study.

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The Oxygen Uptake Plateau—A Critical Review of the Frequently Misunderstood Phenomenon

Sports Medicine ◽

10.1007/s40279-021-01471-4 ◽

2021 ◽

Author(s):

Max Niemeyer ◽

Raphael Knaier ◽

Ralph Beneke

Keyword(s):

Oxygen Uptake ◽

Anaerobic Capacity ◽

Preliminary Evidence ◽

Work Rate ◽

Exercise Tests ◽

Physiological Factors ◽

Cycling Exercise ◽

Rate Relationship ◽

Sampling Intervals ◽

Severe Exercise

AbstractA flattening of the oxygen uptake–work rate relationship at severe exercise indicates the achievement of maximum oxygen uptake $$\left({\text{VO}}_{2\max } \right)$$ VO 2 max . Unfortunately, a distinct plateau $$\left( {{{\text{VO}}}_{2} {\text{pl}}} \right)$$ VO 2 pl at $${{\text{VO}}}_{2\max }$$ VO 2 max is not found in all participants. The aim of this investigation was to critically review the influence of research methods and physiological factors on the $${{\text{VO}}}_{2} {\text{pl}}$$ VO 2 pl incidence. It is shown that many studies used inappropriate definitions or methodical approaches to check for the occurrence of a $${{\text{VO}}}_{2} {\text{pl}}$$ VO 2 pl . In contrast to the widespread assumptions it is unclear whether there is higher $${{\text{VO}}}_{2} {\text{pl}}$$ VO 2 pl incidence in (uphill) running compared to cycling exercise or in discontinuous compared to continuous incremental exercise tests. Furthermore, most studies that evaluated the validity of supramaximal verification phases, reported verification bout durations, which are too short to ensure that $${{\text{VO}}}_{2\max }$$ VO 2 max have been achieved by all participants. As a result, there is little evidence for a higher $${{\text{VO}}}_{2} {\text{pl}}$$ VO 2 pl incidence and a corresponding advantage for the diagnoses of $${{\text{VO}}}_{2\max }$$ VO 2 max when incremental tests are supplemented by supramaximal verification bouts. Preliminary evidence suggests that the occurrence of a $${{\text{VO}}}_{2} {\text{pl}}$$ VO 2 pl in continuous incremental tests is determined by physiological factors like anaerobic capacity, $${{\text{VO}}}_{2}$$ VO 2 -kinetics and accumulation of metabolites in the submaximal intensity domain. Subsequent studies should take more attention to the use of valid $${{\text{VO}}}_{2} {\text{pl}}$$ VO 2 pl definitions, which require a cut-off at ~ 50% of the submaximal $${{\text{VO}}}_{2}$$ VO 2 increase and rather large sampling intervals. Furthermore, if verification bouts are used to verify the achievement of $${{\text{VO}}}_{{2{\text{peak}}}}$$ VO 2 peak /$${{\text{VO}}}_{2\max }$$ VO 2 max , it should be ensured that they can be sustained for sufficient durations.

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