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.

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.

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)

Effect of inspired O2 concentration on leg lactate release during incremental exercise

1996 ◽  
Vol 81 (1) ◽  
pp. 246-251 ◽  
Author(s):  
D. R. Knight ◽  
D. C. Poole ◽  
M. C. Hogan ◽  
D. E. Bebout ◽  
P. D. Wagner
Keyword(s):  
Blood Lactate ◽  
Power Output ◽  
Incremental Exercise ◽  
Venous Blood Flow ◽  
Maximal Power ◽  
Maximal Power Output ◽  
Lactate Accumulation ◽  
Lactate Release ◽  
O2 Concentration ◽  
Blood Lactate Accumulation

The normal rate of blood lactate accumulation during exercise is increased by hypoxia and decreased by hyperoxia. It is not known whether these changes are primarily determined by the lactate release in locomotory muscles or other tissues. Eleven men performed cycle exercise at 20, 35, 50, 92, and 100% of maximal power output while breathing 12, 21, and 100% O2. Leg lactate release was calculated at each stage of exercise as the product of femoral venous blood flow (thermodilution method) and femoral arteriovenous difference in blood lactate concentrations. Regression analysis showed that leg lactate release accounted for 90% of the variability in mean arterial lactate concentration at 20-92% maximal power output. This relationship was described by a regression line with a slope of 0.28 +/- 0.02 min/l and a y-intercept of 1.06 +/- 0.38 mmol/l (r2 = 0.90). There was no effect of inspired O2 concentration on this relationship (P > 0.05). We conclude that during continuous incremental exercise to fatigue the effect of inspired O2 concentration on blood lactate accumulation is principally determined by the rate of net lactate release in blood vessels of the locomotory muscles.

Catecholamine and blood lactate responses to incremental rowing and running exercise

1994 ◽  
Vol 76 (3) ◽  
pp. 1144-1149 ◽  
Author(s):  
A. Weltman ◽  
C. M. Wood ◽  
C. J. Womack ◽  
S. E. Davis ◽  
J. L. Blumer ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Blood Lactate ◽  
Venous Catheter ◽  
Incremental Exercise ◽  
Plasma Epinephrine ◽  
O2 Uptake ◽  
Running Exercise ◽  
Rowing Ergometer ◽  
Per Se

Ten collegiate rowers performed discontinuous incremental exercise to their tolerable limit on two occasions: once on a rowing ergometer and once on a treadmill. Ventilation and pulmonary gas exchange were monitored continuously, and blood was sampled from a venous catheter located in the back of the hand or forearm for determination of blood lactate ([La]) and plasma epinephrine ([Epi]) and norepinephrine ([NE]) concentrations. Thresholds for lactate (LT), epinephrine (Epi-T), and norepinephrine (NE-T) were determined for each subject under each condition and defined as breakpoints when plotted as a function of O2 uptake (VO2). For running, LT (3.76 +/- 0.18 l/min) was lower (P < 0.05) than Epi-T (4.35 +/- 0.14 l/min) and NE-T (4.04 +/- 0.19 l/min). For rowing, LT (3.35 +/- 0.16 l/min) was lower (P < 0.05) than Epi-T (3.72 +/- 0.22 l/min) and NE-T (3.70 +/- 0.18 l/min) and was lower (P < 0.05) than LT for running. Within each mode of exercise, Epi-T and NE-T did not differ. Because LT occurred at a significantly lower VO2 than either Epi-T or NE-T, we conclude that catecholamine thresholds, per se, were not the cause of LT. However, for both modes of exercise LT occurred at a plasma [Epi] of approximately 200–250 pg/ml (rowing, 221 +/- 48 pg/ml; running, 245 +/- 45 pg/ml); these concentrations are consistent with the plasma [Epi] reported necessary for eliciting increments in blood [La] during Epi infusion at rest. Plasma [NE] at LT differed significantly between modes (rowing, 820 +/- 127 pg/ml; running, 1,712 +/- 217 pg/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Physiological Responses and Predictors of Performance in a Simulated Competitive Ski Mountaineering Race

2021 ◽  
pp. 250-257
Author(s):  
Michael Lasshofer ◽  
John Seifert ◽  
Anna-Maria Wörndle ◽  
Thomas Stöggl
Keyword(s):  
Laboratory Test ◽  
Power Output ◽  
Ventilatory Threshold ◽  
Elite Athletes ◽  
Physiological Responses ◽  
Performance Parameters ◽  
Ramp Test ◽  
The Past ◽  
Treadmill Speed ◽  
And Performance

Competitive ski mountaineering (SKIMO) has achieved great popularity within the past years. However, knowledge about the predictors of performance and physiological response to SKIMO racing is limited. Therefore, 21 male SKIMO athletes split into two performance groups (elite: VO2max 71.2 ± 6.8 ml· min-1· kg-1 vs. sub-elite: 62.5 ± 4.7 ml· min-1· kg-1) were tested and analysed during a vertical SKIMO race simulation (523 m elevation gain) and in a laboratory SKIMO specific ramp test. In both cases, oxygen consumption (VO2), heart rate (HR), blood lactate and cycle characteristics were measured. During the race simulation, the elite athletes were approximately 5 min faster compared with the sub-elite (27:15 ± 1:16 min; 32:31 ± 2:13 min; p < 0.001). VO2 was higher for elite athletes during the race simulation (p = 0.046) and in the laboratory test at ventilatory threshold 2 (p = 0.005) and at maximum VO2 (p = 0.003). Laboratory maximum power output is displayed as treadmill speed and was higher for elite than sub-elite athletes (7.4 ± 0.3 km h-1; 6.6 ± 0.3 km h-1; p < 0.001). Lactate values were higher in the laboratory maximum ramp test than in the race simulation (p < 0.001). Pearson’s correlation coefficient between race time and performance parameters was highest for velocity and VO2 related parameters during the laboratory test (r > 0.6). Elite athletes showed their superiority in the race simulation as well as during the maximum ramp test. While HR analysis revealed a similar strain to both cohorts in both tests, the superiority can be explainable by higher VO2 and power output. To further push the performance of SKIMO athletes, the development of named factors like power output at maximum and ventilatory threshold 2 seems crucial.

Time Spent Near V˙O2max During Different Cycling Self-Paced Interval Training Protocols

2020 ◽  
pp. 1-7
Author(s):  
Cristiano Dall’ Agnol ◽  
Tiago Turnes ◽  
Ricardo Dantas De Lucas
Keyword(s):  
Power Output ◽  
Perceived Exertion ◽  
Recovery Period ◽  
Interval Training ◽  
Exercise Duration ◽  
Rating Of Perceived Exertion ◽  
Recovery Ratio ◽  
Active Recovery ◽  
Mean Power ◽  
Work Recovery

Purpose: Cyclists may increase exercise intensity by prolonging exercise duration and/or shortening the recovery period during self-paced interval training, which could impact the time spent near . Thus, the main objective of this study was to compare the time spent near during 4 different self-paced interval training sessions. Methods: After an incremental test, 11 cyclists (mean [SD]: age = 34.4 [6.2] y; ) performed in a randomized order 4 self-paced interval training sessions characterized by a work–recovery ratio of 4:1 or 2:1. Sessions comprised 4 repetitions of 4 minutes of cycling with 1 minute (4/1) or 2 minutes (4/2) of active recovery or 8 minutes of cycling with 2 minutes (8/2) or 4 minutes (8/4) of active recovery. Time spent at 90% to 94% (), ≥95% (), and 90% to 100% () was analyzed in absolute terms and relative to the total work duration. Power output, heart rate, blood lactate, and rating of perceived exertion were compared. Results: The 8/4 session provided higher absolute and than 8/2 (P = .015 and .029) and 4/1 (P = .002 and .047). The 4/2 protocol elicited higher relative (47.7% [26.9%]) and (23.5% [22.7%]) than 4/1 (P = .015 and .028) and 8/2 (P < .01). Session 4/2 (275 [23] W) elicited greater mean power output (P < .01) than 4/1 (261 [27] W), 8/4 (250 [25] W), and 8/2 (234 [23] W). Conclusions: Self-paced interval training composed of 4-minute and 8-minute work periods efficiently elicit , but protocols with a work–recovery ratio of 2:1 (ie, 4/2 and 8/4) could be prioritized to maximize .

Design and Evaluation of a Modified Underwater Cycle Ergometer

1996 ◽  
Vol 21 (2) ◽  
pp. 134-148 ◽  
Author(s):  
An A. Chen ◽  
Glen P. Kenny ◽  
Chad E. Johnston ◽  
Gordon G. Giesbrecht
Keyword(s):  
Power Output ◽  
Maximal Exercise ◽  
Exercise Duration ◽  
Cycle Ergometer ◽  
Gear Ratio ◽  
Upright Position ◽  
Exercise Tests ◽  
Maximal Power Output ◽  
Power Outputs ◽  
Key Words Core Temperature

An underwater cycle ergometer was designed consisting of an aluminum cycle frame in water connected with a 1:1 gear ratio to a mechanically braked standard cycle ergometer supported above the water. Three progressive maximal exercise tests were performed (n = 10): (a) the underwater ergometer in water (UEW), (b) underwater ergometer in air (UEA), and (c) a standard cycle ergometer in air (SEA). At submaximal power outputs, oxygen consumption [Formula: see text] and heart rate (HR) were generally lower in the SEA condition (p <.05), indicating that exercise in the upright position was more efficient. Exercise in water (UEW) resulted in lower total exercise duration, maximal HR, and maximal Tes than in air conditions. The upright position (SEA) resulted in greater total exercise duration and maximal power output than the semirecumbent positions. Because of positional differences between the standard and underwater ergometers, air-water comparisons should be made by using the underwater ergometer in water and on land. Key words: core temperature, esophageal temperature, skin temperature, exercise, resistance, work, power output, heat balance, heat loss, heat production, thermoregulation

scholarly journals Curvilinear VO2:Power Output Relationship in a Ramp Test in Professional Cyclists: Possible Association with Blood Hemoglobin Concentration.

2002 ◽  
Vol 52 (1) ◽  
pp. 95-103 ◽  
Author(s):  
Alejandro Lucía ◽  
Jesús Hoyos ◽  
Alfredo Santalla ◽  
Margarita Pérez ◽  
José L. Chicharro
Keyword(s):  
Power Output ◽  
Hemoglobin Concentration ◽  
Ramp Test ◽  
Blood Hemoglobin ◽  
Blood Hemoglobin Concentration

Effect of duration of exercise on excess postexercise O2 consumption

1987 ◽  
Vol 62 (2) ◽  
pp. 485-490 ◽  
Author(s):  
R. Bahr ◽  
I. Ingnes ◽  
O. Vaage ◽  
O. M. Sejersted ◽  
E. A. Newsholme
Keyword(s):  
Rectal Temperature ◽  
Time Course ◽  
Control Experiment ◽  
Respiratory Exchange Ratio ◽  
Exercise Duration ◽  
Cycle Ergometer ◽  
O2 Consumption ◽  
Work Intensity ◽  
O2 Uptake ◽  
Male Subjects

This study was undertaken to determine the effect of exercise duration on the time course and magnitude of excess postexercise O2 consumption (EPOC). Six healthy male subjects exercised on separate days for 80, 40, and 20 min at 70% of maximal O2 consumption on a cycle ergometer. A control experiment without exercise was performed. O2 uptake, respiratory exchange ratio (R), and rectal temperature were monitored while the subjects rested in bed 24 h postexercise. An increase in O2 uptake lasting 12 h was observed for all exercise durations, but no increase was seen after 24 h. The magnitude of 12-h EPOC was proportional to exercise duration and equaled 14.4 +/- 1.2, 6.8 +/- 1.7, and 5.1 +/- 1.2% after 80, 40, and 20 min of exercise, respectively. On the average, 12-h EPOC equaled 15.2 +/- 2.0% of total exercise O2 consumption (EOC). There was no difference in EPOC:EOC for different exercise durations. A linear decrease with exercise duration was observed in R between 2 and 24 h postexercise. No change was observed in recovery rectal temperature. It is concluded that EPOC increases linearly with exercise duration at a work intensity of 70% of maximal O2 consumption.

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