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Gaynor Parfitt - One of the best experts on this subject based on the ideXlab platform.
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a systematic review of methods to predict Maximal Oxygen Uptake from subMaximal open circuit spirometry in healthy adults
Journal of Science and Medicine in Sport, 2015Co-Authors: Harrison Evans, Gaynor Parfitt, Katia Ferrar, Ashleigh E Smith, Roger G EstonAbstract:Abstract Objectives This systematic review aimed to (i) report the accuracy of subMaximal exercise-based predictive equations that incorporate Oxygen Uptake (measured via open circuit spirometry) to predict Maximal Oxygen Uptake ( V ˙ O 2 max ) and (ii) provide a critical reflection of the data to inform health professionals and researchers when selecting a prediction equation. Design Systematic review. Methods A systematic search of MEDLINE, EMBASE (via OvidSP), CINAHL, SPORTDiscus™ (via EBSCO Host) and Scopus databases was undertaken in February 2013. Studies were required to report data on healthy participants aged 18–65y. Following tabulation of extracted data, a narrative synthesis was conducted. Results From a total of 7597 articles screened, 19 studies were included, from which a total of 43 prediction equations were extracted. No significant difference was reported between the measured and predicted V ˙ O 2 max in 28 equations. Pearson's correlation coefficient between the predicted and measured V ˙ O 2 max ranged from r =0.92 to r =0.57. The variables most commonly used in predictive equations were heart rate ( n =19) and rating of perceived exertion ( n =24). Conclusions Overall, subMaximal exercise-based equations using open circuit spirometry to predict V ˙ O 2 max are moderately to highly accurate. The heart rate and rating of perceived exertion methods of predicting V ˙ O 2 max were of similar accuracy. Important factors to consider when selecting a predictive equation include: the level of exertion required; participant medical conditions or medications; the validation population; mode of ergometry; time and resources available for familiarisation trials; and the level of bias of the study from which equations are derived.
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prediction of Maximal Oxygen Uptake in sedentary males from a perceptually regulated sub Maximal graded exercise test
Journal of Sports Sciences, 2008Co-Authors: Roger G Eston, Danielle Lambrick, K E Sheppard, Gaynor ParfittAbstract:The purpose of this study was to assess the validity of predicting the Maximal Oxygen Uptake (VO2(max)) of sedentary men from sub-Maximal VO2 values obtained during a perceptually regulated exercise test. Thirteen healthy, sedentary males aged 29-52 years completed five graded exercise tests on a cycle ergometer. The first and fifth test involved a graded exercise test to determine VO2(max). The two Maximal graded exercise tests were separated by three sub-Maximal graded exercise tests, perceptually regulated at 3-min RPE intensities of 9, 11, 13, 15, and 17 on the Borg ratings of perceived exertion (RPE) scale, in that order. After confirmation that individual linear regression models provided the most appropriate fit to the data, the regression lines for the perceptual ranges 9-17, 9-15, and 11-17 were extrapolated to RPE 20 to predict VO2(max). There were no significant differences between VO2(max) values from the graded exercise tests (mean 43.9 ml x kg(-1) x min(-1), s = 6.3) and predicted VO2(max) values for the perceptual ranges 9-17 (40.7 ml x kg(-1) x min(-1), s = 2.2) and RPE 11-17 (42.5 ml x kg(-1) x min(-1), s = 2.3) across the three trials. The predicted VO2(max) from the perceptual range 9-15 was significantly lower (P < 0.05) (37.7 ml x kg(-1) x min(-1), s = 2.3). The intra-class correlation coefficients between actual and predicted VO2(max) for RPE 9-17 and RPE 11-17 across trials ranged from 0.80 to 0.87. Limits of agreement analysis on actual and predicted VO2 values (bias +/- 1.96 x S(diff)) were 3.4 ml x kg(-1) x min(-1) (+/- 10.7), 2.4 ml x kg(-1) x min(-1) (+/- 9.9), and 3.7 ml x kg(-1) x min(-1) (+/- 12.8) (trials 1, 2, and 3, respectively) of RPE range 9-17. Results suggest that a sub-Maximal, perceptually guided graded exercise test provides acceptable estimates of VO2(max) in young to middle-aged sedentary males.
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the validity of predicting Maximal Oxygen Uptake from perceptually regulated graded exercise tests of different durations
European Journal of Applied Physiology, 2006Co-Authors: Roger G Eston, James Faulkner, Elizabeth A Mason, Gaynor ParfittAbstract:The purpose of this study was to assess the validity of predicting Maximal Oxygen Uptake (\(\dot{V}\rm O_2\)max) from sub-Maximal \(\dot{V}\rm O_2\) values elicited during perceptually regulated exercise tests of 2- and 4-min duration. Nineteen physically active men and women (age range 19–23 years) volunteered to participate in two graded exercise tests to volitional exhaustion to measure \(\dot{V}\rm O_2\)max (\(\dot{V}\rm O_2\)maxGXT), at the beginning and end of a 2-week period, and four incremental, perceptually regulated tests to predict \(\dot{V}\rm O_2\)max in the intervening period. Effort production tests comprised 2 × 2-min and 2 × 4-min bouts on a cycle ergometer, perceptually regulated at intensities of 9, 11, 13, 15 and 17 on the Borg 6-20 rating of perceived (RPE) scale, in that order. Individual linear relationships between RPE and \(\dot{V}\rm O_2\) for RPE ranges of 9–17, 11–17 and 9–15 were extrapolated to RPE 20 to predict \(\dot{V}\rm O_2\)max. The prediction of \(\dot{V}\rm O_2\)max was not moderated by gender. Although, \(\dot{V}\rm O_2\)max estimated from RPE 9–17 of trial 1 of the 2-min protocol was significantly lower (P < 0.05) than \(\dot{V}\rm O_2\)maxGXT and \(\dot{V}\rm O_2\)max predicted from the 4-min trials, the \(\dot{V}\rm O_2\)max predicted from trial 2 of the 2-min protocol was a more accurate prediction of \(\dot{V}\rm O_2\)maxGXT across all trials. The intraclass correlation coefficient (R) was also higher between \(\dot{V}\rm O_2\)maxGXT and \(\dot{V}\rm O_2\)max predicted from trial 2 of the 2-min protocol compared to both trials in the 4-min protocol (R = 0.95, 0.88 and 0.79, respectively). Similar results were observed for RPE ranges 9–15 and 11–17. Results suggest that a sub-Maximal, perceptually guided, graded exercise protocol, particularly of a 2-min duration, provides acceptable estimates of Maximal aerobic power, which are not moderated by gender.
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the validity of predicting Maximal Oxygen Uptake from a perceptually regulated graded exercise test
European Journal of Applied Physiology, 2005Co-Authors: Roger G Eston, Kevin L Lamb, Gaynor Parfitt, Nicholas KingAbstract:The purpose of this study was to assess the validity of predicting Maximal Oxygen Uptake _ V O2max from sub-Maximal _ V O2 values elicited during a percep- tually-regulated exercise test. We hypothesised that the strong relationship between the ratings of perceived exertion (RPE) and _ V O2 would enable _ V O2max to be predicted and that this would improve with practice. Ten male volunteers performed a graded exercise test (GXT) to establish _ V O2max followed by three sub-Maximal RPE production protocols on a cycle ergometer, each sepa- rated by a period of 48 h. The perceptually-regulated trials were conducted at intensities of 9, 11, 13, 15 and 17 on the RPE scale, in that order. _ V O2 and HR were measured continuously and recorded at the end of each 4 min stage. Individual's RPE values yielded correla- tions in the range 0.92-0.99 across the three production trials. There were no significant differences between measured _
Roger G Eston - One of the best experts on this subject based on the ideXlab platform.
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subMaximal perceptually regulated exercise testing predicts Maximal Oxygen Uptake a meta analysis study
Sports Medicine, 2016Co-Authors: Jeremy Coquart, Montassar Tabben, Abdulaziz Farooq, Claire Tourny, Roger G EstonAbstract:Recently, several authors have proposed the use of a subMaximal ‘perceptually regulated exercise test’ (PRET) to predict Maximal Oxygen Uptake ( $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ ). The PRET involves asking the individual to self-regulate a series of short bouts of exercise corresponding to pre-set ratings of perceived exertion (RPE). The individual linear relationship between RPE and Oxygen Uptake (RPE: $$ \dot{V}{\text{O}}_{2} $$ ) is then extrapolated to the $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ , which corresponds to the theoretical Maximal RPE (RPE20). Studies suggest that prediction accuracy from this method may be better improved during a second PRET. Similarly, some authors have recommended an extrapolation to RPE19 rather than RPE20. The purpose of the meta-analysis was to examine the validity of the method of predicting $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ from the RPE: $$ \dot{V}{\text{O}}_{2} $$ during a PRET, and to determine the level of agreement and accuracy of predicting $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ from an initial PRET and retest using RPE19 and RPE20. From a systematic search of the literature, 512 research articles were identified. The eligible manuscripts were those which used the relationship between the RPE≤15 and $$ \dot{V}{\text{O}}_{2} $$ , and used only the Borg’s RPE scale. Ten studies (n = 274 individuals) were included. For each study, actual and predicted $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ from four subgroup outcomes (RPE19 in the initial test, RPE19 in the retest, RPE20 in the initial test, RPE20 in the retest) were identified, and then compared. The magnitude of the difference regardless of subgroup outcomes was examined to determine if it is better to predict $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ from extrapolation to RPE19 or RPE20. The magnitude of differences was examined for the best PRET (test vs retest). The results revealed that $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ may be predicted from RPE: $$ \dot{V}{\text{O}}_{2} $$ during PRET in different populations and in various PRET modalities, regardless of the subgroup outcomes. To obtain greater accuracy of predictions, extrapolation to RPE20 during a retest may be recommended. The included studies reported poor selection bias and data collection methods. The $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ may be predicted from RPE: $$ \dot{V}{\text{O}}_{2} $$ during PRET, especially when $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$ is extrapolated to RPE20 during a second PRET.
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a systematic review of methods to predict Maximal Oxygen Uptake from subMaximal open circuit spirometry in healthy adults
Journal of Science and Medicine in Sport, 2015Co-Authors: Harrison Evans, Gaynor Parfitt, Katia Ferrar, Ashleigh E Smith, Roger G EstonAbstract:Abstract Objectives This systematic review aimed to (i) report the accuracy of subMaximal exercise-based predictive equations that incorporate Oxygen Uptake (measured via open circuit spirometry) to predict Maximal Oxygen Uptake ( V ˙ O 2 max ) and (ii) provide a critical reflection of the data to inform health professionals and researchers when selecting a prediction equation. Design Systematic review. Methods A systematic search of MEDLINE, EMBASE (via OvidSP), CINAHL, SPORTDiscus™ (via EBSCO Host) and Scopus databases was undertaken in February 2013. Studies were required to report data on healthy participants aged 18–65y. Following tabulation of extracted data, a narrative synthesis was conducted. Results From a total of 7597 articles screened, 19 studies were included, from which a total of 43 prediction equations were extracted. No significant difference was reported between the measured and predicted V ˙ O 2 max in 28 equations. Pearson's correlation coefficient between the predicted and measured V ˙ O 2 max ranged from r =0.92 to r =0.57. The variables most commonly used in predictive equations were heart rate ( n =19) and rating of perceived exertion ( n =24). Conclusions Overall, subMaximal exercise-based equations using open circuit spirometry to predict V ˙ O 2 max are moderately to highly accurate. The heart rate and rating of perceived exertion methods of predicting V ˙ O 2 max were of similar accuracy. Important factors to consider when selecting a predictive equation include: the level of exertion required; participant medical conditions or medications; the validation population; mode of ergometry; time and resources available for familiarisation trials; and the level of bias of the study from which equations are derived.
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prediction of Maximal Oxygen Uptake in sedentary males from a perceptually regulated sub Maximal graded exercise test
Journal of Sports Sciences, 2008Co-Authors: Roger G Eston, Danielle Lambrick, K E Sheppard, Gaynor ParfittAbstract:The purpose of this study was to assess the validity of predicting the Maximal Oxygen Uptake (VO2(max)) of sedentary men from sub-Maximal VO2 values obtained during a perceptually regulated exercise test. Thirteen healthy, sedentary males aged 29-52 years completed five graded exercise tests on a cycle ergometer. The first and fifth test involved a graded exercise test to determine VO2(max). The two Maximal graded exercise tests were separated by three sub-Maximal graded exercise tests, perceptually regulated at 3-min RPE intensities of 9, 11, 13, 15, and 17 on the Borg ratings of perceived exertion (RPE) scale, in that order. After confirmation that individual linear regression models provided the most appropriate fit to the data, the regression lines for the perceptual ranges 9-17, 9-15, and 11-17 were extrapolated to RPE 20 to predict VO2(max). There were no significant differences between VO2(max) values from the graded exercise tests (mean 43.9 ml x kg(-1) x min(-1), s = 6.3) and predicted VO2(max) values for the perceptual ranges 9-17 (40.7 ml x kg(-1) x min(-1), s = 2.2) and RPE 11-17 (42.5 ml x kg(-1) x min(-1), s = 2.3) across the three trials. The predicted VO2(max) from the perceptual range 9-15 was significantly lower (P < 0.05) (37.7 ml x kg(-1) x min(-1), s = 2.3). The intra-class correlation coefficients between actual and predicted VO2(max) for RPE 9-17 and RPE 11-17 across trials ranged from 0.80 to 0.87. Limits of agreement analysis on actual and predicted VO2 values (bias +/- 1.96 x S(diff)) were 3.4 ml x kg(-1) x min(-1) (+/- 10.7), 2.4 ml x kg(-1) x min(-1) (+/- 9.9), and 3.7 ml x kg(-1) x min(-1) (+/- 12.8) (trials 1, 2, and 3, respectively) of RPE range 9-17. Results suggest that a sub-Maximal, perceptually guided graded exercise test provides acceptable estimates of VO2(max) in young to middle-aged sedentary males.
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the validity of predicting Maximal Oxygen Uptake from perceptually regulated graded exercise tests of different durations
European Journal of Applied Physiology, 2006Co-Authors: Roger G Eston, James Faulkner, Elizabeth A Mason, Gaynor ParfittAbstract:The purpose of this study was to assess the validity of predicting Maximal Oxygen Uptake (\(\dot{V}\rm O_2\)max) from sub-Maximal \(\dot{V}\rm O_2\) values elicited during perceptually regulated exercise tests of 2- and 4-min duration. Nineteen physically active men and women (age range 19–23 years) volunteered to participate in two graded exercise tests to volitional exhaustion to measure \(\dot{V}\rm O_2\)max (\(\dot{V}\rm O_2\)maxGXT), at the beginning and end of a 2-week period, and four incremental, perceptually regulated tests to predict \(\dot{V}\rm O_2\)max in the intervening period. Effort production tests comprised 2 × 2-min and 2 × 4-min bouts on a cycle ergometer, perceptually regulated at intensities of 9, 11, 13, 15 and 17 on the Borg 6-20 rating of perceived (RPE) scale, in that order. Individual linear relationships between RPE and \(\dot{V}\rm O_2\) for RPE ranges of 9–17, 11–17 and 9–15 were extrapolated to RPE 20 to predict \(\dot{V}\rm O_2\)max. The prediction of \(\dot{V}\rm O_2\)max was not moderated by gender. Although, \(\dot{V}\rm O_2\)max estimated from RPE 9–17 of trial 1 of the 2-min protocol was significantly lower (P < 0.05) than \(\dot{V}\rm O_2\)maxGXT and \(\dot{V}\rm O_2\)max predicted from the 4-min trials, the \(\dot{V}\rm O_2\)max predicted from trial 2 of the 2-min protocol was a more accurate prediction of \(\dot{V}\rm O_2\)maxGXT across all trials. The intraclass correlation coefficient (R) was also higher between \(\dot{V}\rm O_2\)maxGXT and \(\dot{V}\rm O_2\)max predicted from trial 2 of the 2-min protocol compared to both trials in the 4-min protocol (R = 0.95, 0.88 and 0.79, respectively). Similar results were observed for RPE ranges 9–15 and 11–17. Results suggest that a sub-Maximal, perceptually guided, graded exercise protocol, particularly of a 2-min duration, provides acceptable estimates of Maximal aerobic power, which are not moderated by gender.
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the validity of predicting Maximal Oxygen Uptake from a perceptually regulated graded exercise test
European Journal of Applied Physiology, 2005Co-Authors: Roger G Eston, Kevin L Lamb, Gaynor Parfitt, Nicholas KingAbstract:The purpose of this study was to assess the validity of predicting Maximal Oxygen Uptake _ V O2max from sub-Maximal _ V O2 values elicited during a percep- tually-regulated exercise test. We hypothesised that the strong relationship between the ratings of perceived exertion (RPE) and _ V O2 would enable _ V O2max to be predicted and that this would improve with practice. Ten male volunteers performed a graded exercise test (GXT) to establish _ V O2max followed by three sub-Maximal RPE production protocols on a cycle ergometer, each sepa- rated by a period of 48 h. The perceptually-regulated trials were conducted at intensities of 9, 11, 13, 15 and 17 on the RPE scale, in that order. _ V O2 and HR were measured continuously and recorded at the end of each 4 min stage. Individual's RPE values yielded correla- tions in the range 0.92-0.99 across the three production trials. There were no significant differences between measured _
Marek Zatoń - One of the best experts on this subject based on the ideXlab platform.
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predicting changes in Maximal Oxygen Uptake in response to polarized training sprint interval training high intensity interval training and endurance training in mountain bike cyclists
Journal of Strength and Conditioning Research, 2020Co-Authors: Rafał Hebisz, Paulina Hebisz, Kamil Michalik, Natalia Danek, Marek ZatońAbstract:Hebisz, R, Hebisz, P, Danek, N, Michalik, K, and Zaton, M. Predicting changes in Maximal Oxygen Uptake in response to polarized training (sprint interval training, high-intensity interval training, and endurance training) in mountain bike cyclists. J Strength Cond Res XX(X): 000-000, 2020-The aim of this study was to determine the predictors of change in Maximal Oxygen Uptake (ΔV[Combining Dot Above]O2max) in response to a polarized training program. Twenty well-trained mountain bike cyclists completed an 8-week intervention of sprint interval training (SIT) (8-16 30-second Maximal sprints), high-intensity interval training (4-6 bouts at 85-95% Maximal aerobic power), and endurance training (2-3 hours cycling at 70-80% power at the ventilatory threshold). An incremental exercise test was performed to determine preintervention and postintervention Maximal Oxygen Uptake (V[Combining Dot Above]O2max) and Maximal pulmonary ventilation (VEmax) normalized to lean body mass (LBM). The frequency and time domain of heart rate variability (HRV) was also determined during recovery after moderate warm-up in the first and last SIT. Training status was quantified as the total distance cycled in the previous year. V[Combining Dot Above]O2max, VEmax, and the root mean square of the successive differences of normal-to-normal time interval between heartbeats (RMSSD), which is the time domain of HRV all increased significantly. Multiple significant correlations were observed between ΔV[Combining Dot Above]O2max and training status and baseline measures of VEmax·LBM, RMSSD, and V[Combining Dot Above]O2max·LBM and a regression equation was developed (r = 0.87, r = 0.76; p = 0.0001). The change in V[Combining Dot Above]O2max in response to polarized training can be predicted with high accuracy based on several measurable variables.
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Peak Oxygen Uptake in a sprint interval testing protocol vs. Maximal Oxygen Uptake in an incremental testing protocol and their relationship with cross-country mountain biking performance.
Applied physiology nutrition and metabolism = Physiologie appliquee nutrition et metabolisme, 2016Co-Authors: Rafał Hebisz, Paulina Hebisz, Marek Zatoń, Kamil MichalikAbstract:In the literature, the exercise capacity of cyclists is typically assessed using incremental and endurance exercise tests. The aim of the present study was to confirm whether peak Oxygen Uptake (VO2peak) attained in a sprint interval testing protocol correlates with cycling performance, and whether it corresponds to Maximal Oxygen Uptake (VO2max) determined by an incremental testing protocol. A sample of 28 trained mountain bike cyclists executed 3 performance tests: (i) incremental testing protocol (ITP) in which the participant cycled to volitional exhaustion, (ii) sprint interval testing protocol (SITP) composed of four 30 s Maximal intensity cycling bouts interspersed with 90 s recovery periods, (iii) competition in a simulated mountain biking race. Oxygen Uptake, pulmonary ventilation, work, and power output were measured during the ITP and SITP with postexercise blood lactate and hydrogen ion concentrations collected. Race times were recorded. No significant inter-individual differences were observed in regards to any of the ITP-associated variables. However, 9 individuals presented significantly increased Oxygen Uptake, pulmonary ventilation, and work output in the SITP compared with the remaining cyclists. In addition, in this group of 9 cyclists, Oxygen Uptake in SITP was significantly higher than in ITP. After the simulated race, this group of 9 cyclists achieved significantly better competition times (99.5 ± 5.2 min) than the other cyclists (110.5 ± 6.7 min). We conclude that mountain bike cyclists who demonstrate higher peak Oxygen Uptake in a sprint interval testing protocol than Maximal Oxygen Uptake attained in an incremental testing protocol demonstrate superior competitive performance.
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concomitant application of sprint and high intensity interval training on Maximal Oxygen Uptake and work output in well trained cyclists
European Journal of Applied Physiology, 2016Co-Authors: Paulina Hebisz, Rafał Hebisz, Marek Zatoń, Bartosz Ochmann, Natalia MielnikAbstract:Purpose In this study, we compared the effects of two different training modalities on Maximal Oxygen Uptake and work output.
J P Koralsztein - One of the best experts on this subject based on the ideXlab platform.
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intermittent runs at the velocity associated with Maximal Oxygen Uptake enables subjects to remain at Maximal Oxygen Uptake for a longer time than intense but subMaximal runs
European Journal of Applied Physiology, 2000Co-Authors: Veronique Billat, Jean Slawinski, V Bocquet, A Demarle, Laurent Lafitte, Patrick Chassaing, J P KoralszteinAbstract:Interval training consisting of brief high intensity repetitive runs (30 s) alternating with periods of complete rest (30 s) has been reported to be efficient in improving Maximal Oxygen Uptake (VO2max) and to be tolerated well even by untrained persons. However, these studies have not investigated the effects of the time spent at VO2max which could be an indicator of the benefit of training. It has been reported that periods of continuous running at a velocity intermediate between that of the lactate threshold (vLT) and that associated with VO2max (vVO2max) can allow subjects to reach VO2max due to an additional slow component of Oxygen Uptake. Therefore, the purpose of this study was to compare the times spent at VO2max during an interval training programme and during continuous strenuous runs. Eight long-distance runners took part in three Maximal tests on a synthetic track (400 m) whilst breathing through a portable, telemetric metabolic analyser: they comprised firstly, an incremental test which determined vLT, VO2max [59.8 (SD 5.4) ml.min-1; kg-1], vVO2max [18.5 (SD 1.2) km.h-1], secondly, an interval training protocol consisting of alternately running at 100% and at 50% of vVO2max (30 s each); and thirdly, a continuous high intensity run at vLT + 50% of the difference between vLT and vVO2max [i.e. v delta 50: 16.9 (SD 1.00) km.h-1 and 91.3 (SD 1.6)% vVO2max]. The first and third tests were performed in random order and at 2-day intervals. In each case the subjects warmed-up for 15 min at 50% of vVO2max. The results showed that in more than half of the cases the v delta 50 run allowed the subjects to reach VO2max, but the time spent specifically at VO2max was much less than that during the alternating low/high intensity exercise protocol [2 min 42 s (SD 3 min 09 s) for v delta 50 run vs 7 min 51 s (SD 6 min 38 s) in 19 (SD 5) interval runs]. The blood lactate responses were less pronounced in the interval runs than for the v delta 50 runs, but not significantly so [6.8 (SD 2.2) mmol.l-1 vs 7.5 (SD 2.1) mmol.l-1]. These results do not allow us to speculate as to the chronic effects of these two types of training at VO2max.
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intermittent runs at the velocity associated with Maximal Oxygen Uptake enables subjects to remain at Maximal Oxygen Uptake for a longer time than intense but subMaximal runs
European Journal of Applied Physiology, 2000Co-Authors: Veronique Billat, Jean Slawinski, V Bocquet, A Demarle, Laurent Lafitte, Patrick Chassaing, J P KoralszteinAbstract:Interval training consisting of brief high intensity repetitive runs (30 s) alternating with periods of complete rest (30 s) has been reported to be efficient in improving Maximal Oxygen Uptake (V˙O2max) and to be tolerated well even by untrained persons. However, these studies have not investigated the effects of the time spent at V˙O2max which could be an indicator of the benefit of training. It has been reported that periods of continuous running at a velocity intermediate between that of the lactate threshold (vLT) and that associated with V˙O2max (v V˙ O2max ) can allow subjects to reach V˙O2max due to an additional slow component of Oxygen Uptake. Therefore, the purpose of this study was to compare the times spent at V˙O2max during an interval training programme and during continuous strenuous runs. Eight long-distance runners took part in three Maximal tests on a synthetic track (400 m) whilst breathing through a portable, telemetric metabolic analyser: they comprised firstly, an incremental test which determined vLT, V˙O2max [59.8 (SD 5.4) ml · min−1 · kg−1], v V˙ O2max [18.5 (SD 1.2) km · h−1], secondly, an interval training protocol consisting of alternately running at 100% and at 50% of v V˙ O2max (30 s each); and thirdly, a continuous high intensity run at vLT + 50% of the difference between vLT and v V˙ O2max [i.e. vΔ50: 16.9 (SD 1.00) km · h−1 and 91.3 (SD 1.6)% v V˙ O2max ]. The first and third tests were performed in random order and at 2-day intervals. In each case the subjects warmed-up for 15 min at 50% of v V˙ O2max . The results showed that in more than half of the cases the vΔ50 run allowed the subjects to reach V˙O2max, but the time spent specifically at V˙O2max was much less than that during the alternating low/high intensity exercise protocol [2 min 42 s (SD 3 min 09 s) for vΔ50 run vs 7 min 51 s (SD 6 min 38 s) in 19 (SD 5) interval runs]. The blood lactate responses were less pronounced in the interval runs than for the vΔ50 runs, but not significantly so [6.8 (SD 2.2) mmol · l−1 vs 7.5 (SD 2.1) mmol · l−1]. These results do not allow us to speculate as to the chronic effects of these two types of training at V˙O2max.
Jose A L Calbet - One of the best experts on this subject based on the ideXlab platform.
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contribution of Oxygen extraction fraction to Maximal Oxygen Uptake in healthy young men
Acta Physiologica, 2020Co-Authors: Oyvind Skattebo, Jose A L Calbet, Carlo Capelli, Jostein HallenAbstract:We analysed the importance of systemic and peripheral arteriovenous O2 difference ( a-v¯O2 difference and a-vf O2 difference, respectively) and O2 extraction fraction for Maximal Oxygen Uptake ( V˙O2max ). Fick law of diffusion and the Piiper and Scheid model were applied to investigate whether diffusion versus perfusion limitations vary with V˙O2max . Articles (n = 17) publishing individual data (n = 154) on V˙O2max , Maximal cardiac output ( Q˙max ; indicator-dilution or the Fick method), a-v¯O2 difference (catheters or the Fick equation) and systemic O2 extraction fraction were identified. For the peripheral responses, group-mean data (articles: n = 27; subjects: n = 234) on leg blood flow (LBF; thermodilution), a-vf O2 difference and O2 extraction fraction (arterial and femoral venous catheters) were obtained. Q˙max and two-LBF increased linearly by 4.9-6.0 L · min-1 per 1 L · min-1 increase in V˙O2max (R2 = .73 and R2 = .67, respectively; both P < .001). The a-v¯O2 difference increased from 118-168 mL · L-1 from a V˙O2max of 2-4.5 L · min-1 followed by a reduction (second-order polynomial: R2 = .27). After accounting for a hypoxemia-induced decrease in arterial O2 content with increasing V˙O2max (R2 = .17; P < .001), systemic O2 extraction fraction increased up to ~90% ( V˙O2max : 4.5 L · min-1 ) with no further change (exponential decay model: R2 = .42). Likewise, leg O2 extraction fraction increased with V˙O2max to approach a Maximal value of ~90-95% (R2 = .83). Muscle O2 diffusing capacity and the equilibration index Y increased linearly with V˙O2max (R2 = .77 and R2 = .31, respectively; both P < .01), reflecting decreasing O2 diffusional limitations and accentuating O2 delivery limitations. In conclusion, although O2 delivery is the main limiting factor to V˙O2max , enhanced O2 extraction fraction (≥90%) contributes to the remarkably high V˙O2max in endurance-trained individuals.
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determinants of Maximal Oxygen Uptake in severe acute hypoxia
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2003Co-Authors: Jose A L Calbet, Robert Boushel, Goran Radegran, Hans Sondergaard, Peter D Wagner, Bengt SaltinAbstract:To unravel the mechanisms by which Maximal Oxygen Uptake (V˙o 2 max) is reduced with severe acute hypoxia in humans, nine Danish lowlanders performed incremental cycle ergometer exercise to exhaust...