scholarly journals Prior exercise impairs subsequent performance in an intensity- and duration-dependent manner

2021 ◽  
Author(s):  
Madison M Fullerton ◽  
Louis Passfield ◽  
Martin J. MacInnis ◽  
Danilo Iannetta ◽  
Juan M Murias
Keyword(s):  
Lactate Threshold ◽  
Peak Power ◽  
Constant Load ◽  
Cycle Ergometer ◽  
Dependent Manner ◽  
Incremental Test ◽  
Subsequent Performance ◽  
Prior Exercise ◽  
Subsequent Time ◽  
Constant Load Exercise

Prior constant-load exercise performed for 30-min at or above maximal lactate steady state (MLSSp) significantly impairs subsequent time-to-task failure (TTF) compared with TTF performed without prior exercise. We tested the hypothesis that TTF would decrease in relation to the intensity and the duration of prior exercise compared to a baseline TTF trial. Eleven individuals (6 men, 5 women, 28 ± 8 yrs) completed the following tests on a cycle ergometer (randomly assigned after MLSSp was determined): i) a ramp-incremental test, ii) a baseline TTF trial performed at 80% of peak power (TTFb), iii) five 30-min constant-PO rides at 5% below lactate threshold (LT-5%), halfway between LT and MLSSp (Delta50), 5% below MLSSp (MLSS-5%), MLSSp, and 5% above MLSSp (MLSS+5%), and iv) 15- and 45-min rides at MLSSp (MLSS15 and MLSS45, respectively). Each condition was immediately followed by a TTF trial at 80% of peak power. Compared to TTFb (330 ± 52s), there was 8.0 ± 24.1, 23.6 ± 20.2, 41.0 ± 14.8, 52.2 ± 18.9, and 75.4 ± 7.4% reduction in TTF following LT-5%, Delta50, MLSS-5%, MLSSp, and MLSS+5%, respectively. Following MLSS15 and MLSS45 there were 29.0 ± 20.1 and 69.4 ± 19.6% reductions in TTF, respectively (P <0.05). It is concluded that TTF is reduced following prior exercise of varying duration at MLSSp and at submaximal intensities below MLSS. Novelty: •Prior constant-PO exercise, performed at intensities below MLSSp, reduces subsequent TTF performance. •Subsequent TTF performance is reduced in a linear fashion following an increase in the duration of constant-PO exercise at MLSSp.

Evaluation of the Monark Wingate Ergometer by Direct Measurement of Resistance and Velocity

2001 ◽  
Vol 26 (6) ◽  
pp. 543-558 ◽  
Author(s):  
Brian R. Macintosh ◽  
Shirley N. Bryan ◽  
Peter Rishaug ◽  
Stephen R. Norris
Keyword(s):  
Peak Power ◽  
Anaerobic Power ◽  
Constant Load ◽  
Cycle Ergometer ◽  
Moment Of Inertia ◽  
Power Moment ◽  
Correct Calculation ◽  
Load Tests ◽  
The Moment ◽  
Direct Measures

The purpose of this study was to assess the accuracy of the new basket-loaded Wingate ergometer introduced by Monark (Model 834E). Velocity was measured directly from the pedal switch while tension was measured with transducers on each end of the brake lacing. Moment of inertia of the flywheel was determined and accounted for in the calculation of power. Constant load tests (39.24 to 98.1 N), were done at pedaling speeds from 80 to 140 r•min−1 (flywheel angular velocity = 30-50 rad•s−1). The load transmitted to the lacing at the front and back of the flywheel was 95.5 ± 0.8% (mean ± SEM) and 6.71 ± 0.8%, respectively, of the load in the basket. Thus, the resultant tension (front minus back) was on average 88.8 ± 0.57% of the applied load. The velocity recorded by the Monark Wingate Ergometer computer program (MWECP) was the same (100.4 ± 1.56%) as that determined from the pedal switch directly. Five male mountain bikers performed a 30-s all-out test. Peak power calculated by MWECP (1181 ± 55W) was always higher (p < .01) than that calculated from direct measures of tension and velocity (1102 ± 66W), when not taking into account the moment of inertia. These experiments suggest that the basket-loaded Monark Wingate ergometer does not provide a correct calculation of power because of incomplete load transmission to the flywheel. Key words: power, anaerobic power, moment of inertia, cycle ergometer

scholarly journals Gluconeogenesis and hepatic glycogenolysis during exercise at the lactate threshold

2013 ◽  
Vol 114 (3) ◽  
pp. 297-306 ◽  
Author(s):  
Chi-An W. Emhoff ◽  
Laurent A. Messonnier ◽  
Michael A. Horning ◽  
Jill A. Fattor ◽  
Thomas J. Carlson ◽  
...  
Keyword(s):  
Endurance Training ◽  
Exercise Intensity ◽  
Lactate Threshold ◽  
Lactate Concentration ◽  
Glucose Production ◽  
Constant Load ◽  
Metabolic Clearance ◽  
Trained Subjects ◽  
Relative Exercise Intensity ◽  
Constant Load Exercise

Because the maintenance of glycemia is essential during prolonged exercise, we examined the effects of endurance training, exercise intensity, and plasma lactate concentration ([lactate]) on gluconeogenesis (GNG) and hepatic glycogenolysis (GLY) in fasted men exercising at, and just below, the lactate threshold (LT), where GNG precursor lactate availability is high. Twelve healthy men (6 untrained, 6 trained) completed 60 min of constant-load exercise at power outputs corresponding to their individual LT. Trained subjects completed two additional 60-min sessions of constant-load exercise: one at 10% below the LT workload (LT-10%), and the other with a lactate clamp (LT-10%+LC) to match the [lactate] of the LT trial. Flux rates were determined by primed continuous infusion of [6,6-2H2]glucose, [3-13C]lactate, and [13C]bicarbonate tracers during 90 min of rest and 60 min of cycling. Exercise at LT corresponded to 67.6 ± 1.3 and 74.8 ± 1.7% peak O2 consumption in the untrained and trained subjects, respectively ( P < 0.05). Relative exercise intensity was matched between the untrained group at LT and the trained group at LT-10%, and [lactate] during exercise was matched in the LT and LT-10%+LC trials via exogenous lactate infusion. Glucose kinetics (rate of appearance, rate of disposal, and metabolic clearance rate) were augmented with the lactate clamp. GNG was decreased in the trained subjects exercising at LT and LT-10% compared with the untrained subjects, but increasing [lactate] in the LT-10%+LC trial significantly increased GNG (4.4 ± 0.9 mg·kg−1·min−1) compared with its corresponding control (1.7 ± 0.4 mg·kg−1·min−1, P < 0.05). Hepatic GLY was higher in the trained than untrained subjects, but not significantly different across conditions. We conclude that GNG plays an essential role in maintaining total glucose production during exercise in fasted men, regardless of training state. However, endurance training increases the ability to achieve a higher relative exercise intensity and absolute power output at the LT without a significant decrease in GNG. Furthermore, raising systemic precursor substrate availability increases GNG during exercise, but not at rest.

Imagery as a Method of Enhancing Transfer From Trailing to Performance

1990 ◽  
Vol 12 (4) ◽  
pp. 366-375 ◽  
Author(s):  
Geraldine H. Van Gym ◽  
Howard A. Wenger ◽  
Catherine A. Gaul
Keyword(s):  
Peak Power ◽  
Cycle Ergometer ◽  
Power Training ◽  
Subsequent Performance ◽  
Imagery Training ◽  
Cycle Ergometer Test ◽  
Time Interaction ◽  
Significant Difference ◽  
Ergometer Test ◽  
And Control

This study investigated the effect of engaging in imagery in conjunction with nonspecific training on the transfer of the training to performance. Forty subjects were pretested on a Wingate cycle ergometer test for peak power and a 40-m sprint. Subjects were assigned to one of four groups: imagery training (IT), power training (PT), imagery and power training (DPT), and control (C). Following a 6-week training period, all subjects were retested. Although a MANOVA revealed no significant difference between groups on any variable, the groups-by-time interaction was significant. Therefore an analysis of difference scores on both tests was performed. This analysis revealed that although both the IPT and the PT group significantly improved in peak power, only the IPT group improved significantly on the sprint. The results indicate that imagery coupled with nonspecific training contributes to the enhancement of subsequent performance significantly better than does nonspecific training alone.

Sodium Bicarbonate Ingestion Does Not Attenuate the VO2 Slow Component during Constant-Load Exercise

1998 ◽  
Vol 8 (1) ◽  
pp. 60-69 ◽  
Author(s):  
Kristen L. Heck ◽  
Jeffrey A. Potteiger ◽  
Karen L. Nau ◽  
Jan M. Schroeder
Keyword(s):  
Sodium Bicarbonate ◽  
Lactate Threshold ◽  
Slow Component ◽  
Lactate Concentration ◽  
Constant Load ◽  
Bicarbonate Concentration ◽  
Physically Active ◽  
Significant Difference ◽  
Expired Gas ◽  
Constant Load Exercise

We examined the effects of sodium bicarbonate ingestion on the VO2 slow component during constant-load exercise. Twelve physically active males performed two 30-min cycling trials at an intensity above the lactate threshold. Subjects ingested either sodium bicarbonate (BIC) or placebo (PLC) in a randomized. counterbalanced order. Arterialized capillary blood samples were analyzed for pH, bicarbonate concentration ([HCO3−), and lactate concentration ([La]). Expired gas samples were analyzed for oxygen consumption (VO2). The VO2 slow component was defined as the change in VO2 from Minutes 3 and 4 to Minutes 28 and 29. Values for pH and [HCO3−] were significantly higher for BIC compared to PLC. There was no significant difference in [La] between conditions. For both conditions there was a significant time effect for VO2 during exercise: however, no significant difference was observed between BIC and PLC. While extracellular acid-base measures were altered during the BIC trial, sodium bicarbonate ingestion did not attenuate the VO2 slow component during constant-load exercise.

scholarly journals Quantification and Verification of Cardiorespiratory Fitness in Adults with Prehypertension

Sports ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
Dharini M. Bhammar ◽  
Lung-Chang Chien
Keyword(s):  
Cardiorespiratory Fitness ◽  
Statistical Difference ◽  
Constant Load ◽  
Cycle Ergometer ◽  
Work Rate ◽  
Test Results ◽  
Incremental Test ◽  
Incremental Exercise Test ◽  
Increased Risk ◽  
Verification Test

Background: Low cardiorespiratory fitness is associated with increased risk of hypertension and atherosclerosis in adults with prehypertension. The purpose of this study was to quantify cardiorespiratory fitness and to examine the utility of supramaximal constant-load verification testing for validating maximal oxygen uptake (VO2max) attainment in adults with prehypertension. Methods: Eleven adults (four women) with prehypertension (22.5 ± 2.9 y; body mass index (BMI): 24.6 ± 3.2 kg·m2) underwent an incremental exercise test followed 15 min later by a verification test at 105% of maximal work rate on a cycle ergometer. Results: There was no statistical difference in VO2 between the incremental (2.23 ± 0.54 L·min−1) and verification tests (2.28 ± 0.54 L·min−1; p = 0.180). Only three out of eleven participants had a higher VO2 during the verification when compared with the incremental test. If the verification test had not been conducted, one participant would have been incorrectly classified as having low cardiorespiratory fitness based on incremental test results alone. Conclusions: Verification testing validates the attainment of VO2max and can potentially reduce the over-diagnosis of functional impairment (i.e., deconditioning) in adults with prehypertension.

Effect of a Reduced-CHO Diet on the Rate of Perceived Exertion Curve During an Incremental Test

2014 ◽  
Vol 24 (5) ◽  
pp. 532-542 ◽  
Author(s):  
Guilherme Assuncao Ferreira ◽  
Raul Osiecki ◽  
Adriano Eduardo Lima-Silva ◽  
Michel Cardoso de Angelis-Pereira ◽  
Fernando Roberto De-Oliveira
Keyword(s):  
Power Output ◽  
Lactate Threshold ◽  
Perceived Exertion ◽  
Control Diet ◽  
Cycle Ergometer ◽  
Incremental Test ◽  
Physically Active ◽  
Rate Of Perceived Exertion ◽  
Short Period ◽  
Proportional Increase

The objective of this study was to evaluate the effect of a reduced-carbohydrate (reduced-CHO) diet on the rate of perceived exertion (RPE) curve during an incremental test. Nine physically active men performed a progressive incremental test on a cycle ergometer (25 W·2 min−1) after 72 hr on either a control diet (60% CHO) or a reduced-CHO diet (30% CHO). Lactate and RPE thresholds were identified using the Dmax method (DmaxLa and DmaxRPE, respectively). Power output, heart rate and RPE scores in DmaxLa and DmaxRPE were similar between the diets and were not different from each other, regardless of the diet. Lactate values were consistently higher (p < .05) in the control diet compared with the reduced-CHO diet during power output after the lactate breakpoint; however, they were not accompanied by a proportional increase in RPE scores. These results suggest that DmaxRPE and DmaxLa are not dissociated after a short-period reduced-CHO diet, whereas the lactate values after the lactate threshold are reduced with a reduced-CHO diet, although they are not accompanied by alterations in RPE.

scholarly journals The VO2-on Kinetics in Constant Load Exercise Sub-Anaerobic Threshold Reflects Endothelial Function and Dysfunction in Muscle Microcirculation

2015 ◽  
pp. 807-819
Author(s):  
D. MAIONE ◽  
A. F. G. CICERO ◽  
S. BACCHELLI ◽  
E. R. COSENTINO ◽  
D. DEGLI ESPOSTI ◽  
...  
Keyword(s):  
Endothelial Dysfunction ◽  
Endothelial Function ◽  
Anaerobic Threshold ◽  
Nyha Class ◽  
Constant Load ◽  
Cycle Ergometer ◽  
Phase 3 ◽  
Heart Patients ◽  
Highly Sensitive ◽  
Constant Load Exercise

To propose a test to evaluate endothelial function, based on VO2 on-transition kinetics in sub-anaerobic threshold (AT) constant load exercise, we tested healthy subjects and patients with ischemic-hypertensive cardiopathy by two cardiopulmonary tests on a cycle ergometer endowed with an electric motor to overcome initial inertia: a pre-test and, after at least 24 h, one 6 min constant load exercise at 90 % AT. We measured net phase 3 VO2-on kinetics and, by phase 2 time constant (τ), valued endothelial dysfunction. We found shorter τ in repeated tests, shorter time between first and second test, by persisting endothelium-dependent arteriolar vasodilatation and/or several other mechanisms. Reducing load to 80 % and 90 % AT did not produce significant changes in τ of healthy volunteers, while in heart patients an AT load of 70 %, compared to 80 % AT, shortened τ (=4.38±1.65 s, p=0.013). In heart patients, no correlation was found between NYHA class, ejection fraction (EF), and the two variables derived from incremental cycle cardio-pulmonary exercise, as well as between EF and τ; while NYHA class groups were well correlated with τ duration (r=0.92, p=0.0001). Doxazosin and tadalafil also significantly reduced τ. In conclusion, the O2 consumption kinetics during the on-transition of constant load exercise below the anaerobic threshold are highly sensitive to endothelial function in muscular microcirculation, and constitute a marker for the evaluation of endothelial dysfunction.

A Novel Approach for Lactate Threshold Assessment Based on Rating of Perceived Exertion

2013 ◽  
Vol 8 (3) ◽  
pp. 263-270 ◽  
Author(s):  
Nicolas Fabre ◽  
Laurent Mourot ◽  
Livio Zerbini ◽  
Barbara Pellegrini ◽  
Lorenzo Bortolan ◽  
...  
Keyword(s):  
Lactate Threshold ◽  
Perceived Exertion ◽  
Ventilatory Threshold ◽  
Lactate Concentration ◽  
Cycle Ergometer ◽  
Rating Of Perceived Exertion ◽  
Strongly Correlated ◽  
Incremental Test ◽  
Distance Method ◽  
Novel Approach

This study tested the hypothesis that the DMAX (for maximal distance) method could be applied to ratings of perceived exertion (RPE), to propose a novel method for individual detection of the lactate threshold (LT) using RPE alone during an incremental test to exhaustion. Twenty-one participants performed an incremental test on a cycle ergometer. At the end of each stage, lactate concentration was measured and the participants estimated RPE using the Borg CR100 scale. The intensity corresponding to the fixed lactate values of 2 or 4 mmol · L−1(2mM and 4mM), the ventilatory threshold (VT), the respiratory-compensation point (RCP), and the instant of equality of pulmonary gas exchange (RER=1.00) were determined. Lactate (DMAX La) and RPE (DMAX RPE) thresholds were determined using the DMAX method. Oxygen uptake (VO2), heart rate, and power output measured at DMAX RPE and at DMAX La were not statistically different. Bland-Altman plots showed small bias and good agreements when DMAX RPE was compared with the DMAX La and RER=1.00 methods (bias = −0.05% and −2% of VO2max, respectively). Conversely, VO2 from the DMAX RPE method was lower than VO2 at 4 mM and at RCP and was higher than VO2 at 2 mM and at VT. VO2 at DMAX RPE was strongly correlated with VO2 at DMAX La (r = .97), at RER=1.00 (r = .97), at 2 mM (r = .85), at 4 mM (r = .93), at VT (r = .95), and at RCP (r = .95). The combination of the DMAX method with the RPE responses permitted precise and individualized estimates of LT using the DMAX method.

scholarly journals Durée de la récupération et puissance maximale anaérobie au cours de la journée

2003 ◽  
Vol 28 (2) ◽  
pp. 213-224 ◽  
Author(s):  
Guy Falgairette ◽  
François Billaut ◽  
Sophiane Ramdani
Keyword(s):  
Peak Power ◽  
Biological Rhythms ◽  
Cycle Ergometer ◽  
Time Of Day ◽  
Total Work ◽  
Half Time ◽  
Instantaneous Power ◽  
Recovery Processes ◽  
Logarithmic Relationship ◽  
Short Time

Effects of recovery duration (2-3 s, 15 s, 30 s, 1 min, and 2 min) and time of day (9 a.m., 2 p.m., and 6 p.m.) on sprint performance were studied in 9 subjects using a cycle ergometer. The peak power (Ppeak) and the total work performed (W) were determined from changes in instantaneous power, taking into account the inertia of the flywheel. A decrease in Ppeak and W was observed after 15 s and 2-3 s recovery (p < 0.001). A logarithmic relationship (y = 3.92 ln x + 81.5; r = 0.82; n = 9) was found between Ppeak (%Ppeak of the first sprint) and the duration of the recovery (half-time = 14.3 s; SD = 7.6). Data indicated that there was no significant effect of time of day on Ppeak and W, regardless of the duration of recovery. The recovery processes occurred in a very short time and did not seem to be affected by biological rhythms. Key words: performance, diurnal variation, fatigue, ergometry, inertia

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