scholarly journals Determining Validity of Critical Power Estimated Using a Three-Minute All-Out Test in Hot Environments

2021 ◽  
Vol 18 (17) ◽  
pp. 9193
Author(s):  
Yu-Hsuan Kuo ◽  
Ching-Feng Cheng ◽  
Yu-Chi Kuo
Keyword(s):  
High Temperature ◽  
Oxygen Uptake ◽  
Exercise Performance ◽  
Power Output ◽  
Maximal Oxygen Uptake ◽  
Critical Power ◽  
Physiological Stress ◽  
Exercise Tests ◽  
Test Power ◽  
Hot Environments

The aim of this study was to investigate the effects of heat on the validity of end-test power (EP) derived from a 3-min all-out test (3MT), which is considered as an alternative method for determining the conventional critical power. Twelve male cyclists were required to perform incremental exercise tests (IET) and 3MTs in both high temperature (HT; 35 °C) and thermoneutral temperature (NT; 22 °C) environments. Maximal oxygen uptake (VO2max), and first and second ventilatory thresholds (VT1 and VT2, respectively) against the power output (wVO2max, wVT1, and wVT2) were measured during IETs. EP was recorded during the 3MTs. A significant correlation was observed between wVT2 and EP under NT (r = 0.674, p < 0.05) and under HT (r = 0.672, p < 0.05). However, wVO2max, wVT1, wVT2, and EP were significantly higher in NT than in HT (p < 0.05). In conclusion, although the physiological stress induced by HT might impair exercise performance, the EP derived from 3MT can validly estimate wVT2 under HT conditions.

Effect of aerobic training status on both maximal lactate steady state and critical power

2012 ◽  
Vol 37 (4) ◽  
pp. 736-743 ◽  
Author(s):  
Camila Coelho Greco ◽  
Renato Aparecido Corrêa Caritá ◽  
Jeanne Dekerle ◽  
Benedito Sérgio Denadai
Keyword(s):  
Steady State ◽  
Oxygen Uptake ◽  
Aerobic Fitness ◽  
Maximal Oxygen Uptake ◽  
Aerobic Training ◽  
Critical Power ◽  
Training Status ◽  
Maximal Lactate Steady State ◽  
Incremental Test ◽  
Constant Work Rate

This study aimed at assessing the sensitivity of both maximal lactate steady state (MLSS) and critical power (CP) in populations of different aerobic training status to ascertain whether CP is as sensitive as MLSS to a change in aerobic fitness. Seven untrained subjects (UT) (maximal oxygen uptake = 37.4 ± 6.5 mL·kg–1·min–1) and 7 endurance cyclists (T) (maximal oxygen uptake = 62.4 ± 5.2 mL·kg–1·min–1) performed an incremental test for maximal oxygen uptake estimation and several constant work rate tests for MLSS and CP determination. MLSS, whether expressed in mL·kg–1·min–1 (T: 51.8 ± 5.7 vs. UT: 29.0 ± 6.1) or % maximal oxygen uptake (T: 83.1 ± 6.8 vs. UT: 77.1 ± 4.5), was significantly higher in the T group. CP expressed in mL·kg–1·min–1 (T: 56.8 ± 5.1 vs. UT: 33.1 ± 6.3) was significantly higher in the T group as well but no difference was found when expressed in % maximal oxygen uptake (T: 91.1 ± 4.8 vs. UT: 88.3 ± 3.6). Whether expressed in absolute or relative values, MLSS is sensitive to aerobic training status and a good measure of aerobic endurance. Conversely, the improvement in CP with years of training is proportional to those of maximal oxygen uptake. Thus, CP might be less sensitive than MLSS for depicting an enhancement in aerobic fitness.

Ischemic preconditioning of the muscle improves maximal exercise performance but not maximal oxygen uptake in humans

2011 ◽  
Vol 111 (2) ◽  
pp. 530-536 ◽  
Author(s):  
Antonio Crisafulli ◽  
Flavio Tangianu ◽  
Filippo Tocco ◽  
Alberto Concu ◽  
Ombretta Mameli ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Ischemic Preconditioning ◽  
Exercise Performance ◽  
Cell Injury ◽  
Maximal Exercise ◽  
Pulmonary Ventilation ◽  
Anaerobic Capacity ◽  
Maximal Heart Rate ◽  
Exercise Tests ◽  
Maximal Power Output

Brief episodes of nonlethal ischemia, commonly known as “ischemic preconditioning” (IP), are protective against cell injury induced by infarction. Moreover, muscle IP has been found capable of improving exercise performance. The aim of the study was the comparison of standard exercise performances carried out in normal conditions with those carried out following IP, achieved by brief muscle ischemia at rest (RIP) and after exercise (EIP). Seventeen physically active, healthy male subjects performed three incremental, randomly assigned maximal exercise tests on a cycle ergometer up to exhaustion. One was the reference (REF) test, whereas the others were performed after the RIP and EIP sessions. Total exercise time (TET), total work (TW), and maximal power output (Wmax), oxygen uptake (VO2max), and pulmonary ventilation (VEmax) were assessed. Furthermore, impedance cardiography was used to measure maximal heart rate (HRmax), stroke volume (SVmax), and cardiac output (COmax). A subgroup of volunteers ( n = 10) performed all-out tests to assess their anaerobic capacity. We found that both RIP and EIP protocols increased in a similar fashion TET, TW, Wmax, VEmax, and HRmax with respect to the REF test. In particular, Wmax increased by ∼4% in both preconditioning procedures. However, preconditioning sessions failed to increase traditionally measured variables such as VO2max, SVmax, COmax, and anaerobic capacity. It was concluded that muscle IP improves performance without any difference between RIP and EIP procedures. The mechanism of this effect could be related to changes in fatigue perception.

scholarly journals Metabolic consequences of β-alanine supplementation during exhaustive supramaximal cycling and 4000-m time-trial performance

2016 ◽  
Vol 41 (8) ◽  
pp. 864-871 ◽  
Author(s):  
Phillip M. Bellinger ◽  
Clare L. Minahan
Keyword(s):  
Oxygen Uptake ◽  
Power Output ◽  
Maximal Oxygen Uptake ◽  
Anaerobic Power ◽  
Anaerobic Capacity ◽  
Time Trial ◽  
Time To Exhaustion ◽  
Cycling Test ◽  
Cycling Time Trial ◽  
Aerobic And Anaerobic

The present study investigated the effects of β-alanine supplementation on the resultant blood acidosis, lactate accumulation, and energy provision during supramaximal-intensity cycling, as well as the aerobic and anaerobic contribution to power output during a 4000-m cycling time trial (TT). Seventeen trained cyclists (maximal oxygen uptake = 4.47 ± 0.55 L·min−1) were administered 6.4 g of β-alanine (n = 9) or placebo (n = 8) daily for 4 weeks. Participants performed a supramaximal cycling test to exhaustion (equivalent to 120% maximal oxygen uptake) before (PreExh) and after (PostExh) the 4-week supplementation period, as well as an additional postsupplementation supramaximal cycling test identical in duration and power output to PreExh (PostMatch). Anaerobic capacity was quantified and blood pH, lactate, and bicarbonate concentrations were measured pre-, immediately post-, and 5 min postexercise. Subjects also performed a 4000-m cycling TT before and after supplementation while the aerobic and anaerobic contributions to power output were quantified. β-Alanine supplementation increased time to exhaustion (+12.8 ± 8.2 s; P = 0.041) and anaerobic capacity (+1.1 ± 0.7 kJ; P = 0.048) in PostExh compared with PreExh. Performance time in the 4000-m TT was reduced following β-alanine supplementation (−6.3 ± 4.6 s; P = 0.034) and the mean anaerobic power output was likely to be greater (+6.2 ± 4.5 W; P = 0.035). β-Alanine supplementation increased time to exhaustion concomitant with an augmented anaerobic capacity during supramaximal intensity cycling, which was also mirrored by a meaningful increase in the anaerobic contribution to power output during a 4000-m cycling TT, resulting in an enhanced overall performance.

Is Acute Static Stretching Able to Reduce the Time to Exhaustion at Power Output Corresponding to Maximal Oxygen Uptake?

2010 ◽  
Vol 24 (6) ◽  
pp. 1650-1656 ◽  
Author(s):  
Felipe A Samogin Lopes ◽  
Elton M Menegon ◽  
Emerson Franchini ◽  
Valmor Tricoli ◽  
Rômulo C de M. Bertuzzi
Keyword(s):  
Oxygen Uptake ◽  
Power Output ◽  
Maximal Oxygen Uptake ◽  
Time To Exhaustion ◽  
Static Stretching

The validity of predicting maximal oxygen uptake from perceptually regulated graded exercise tests of different durations

2006 ◽  
Vol 97 (5) ◽  
pp. 535-541 ◽  
Author(s):  
Roger G. Eston ◽  
James A. Faulkner ◽  
Elizabeth A. Mason ◽  
Gaynor Parfitt
Keyword(s):  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Exercise Tests ◽  
Graded Exercise

scholarly journals Effects of macro- and micronutrients on exercise-induced hepcidin response in highly trained endurance athletes

2017 ◽  
Vol 42 (10) ◽  
pp. 1036-1043 ◽  
Author(s):  
Dylan T. Dahlquist ◽  
Trent Stellingwerff ◽  
Brad P. Dieter ◽  
Donald C. McKenzie ◽  
Michael S. Koehle
Keyword(s):  
Oxygen Uptake ◽  
Power Output ◽  
Maximal Oxygen Uptake ◽  
Athletic Performance ◽  
Iron Absorption ◽  
Regulatory Protein ◽  
Endurance Athletes ◽  
Warm Up ◽  
Macro And Micronutrients ◽  
Exercise Induced

Iron deficiency has ergolytic effects on athletic performance. Exercise-induced inflammation impedes iron absorption in the digestive tract by upregulating the expression of the iron regulatory protein, hepcidin. Limited research indicates the potential of specific macro- and micronutrients on blunting exercise-induced hepcidin. Therefore, we investigated the effects of postexercise supplementation with protein and carbohydrate (CHO) and vitamins D3 and K2 on the postexercise hepcidin response. Ten highly trained male cyclists (age: 26.9 ± 6.4 years; maximal oxygen uptake: 67.4 ± 4.4 mL·kg–1·min–1 completed 4 cycling sessions in a randomized, placebo-controlled, single-blinded, triple-crossover study. Experimental days consisted of an 8-min warm-up at 50% power output at maximal oxygen uptake, followed by 8 × 3-min intervals at 85% power output at maximal oxygen uptake with 1.5 min at 60% power output at maximal oxygen uptake between each interval. Blood samples were collected pre- and postexercise, and at 3 h postexercise. Three different drinks consisting of CHO (75 g) and protein (25 g) with (VPRO) or without (PRO) vitamins D3 (5000 IU) and K2 (1000 μg), or a zero-calorie control drink (PLA) were consumed immediately after the postexercise blood sample. Results showed that the postexercise drinks had no significant (p ≥ 0.05) effect on any biomarker measured. There was a significant (p < 0.05) increase in hepcidin and interleukin-6 following intense cycling intervals in the participants. Hepcidin increased significantly (p < 0.05) from baseline (nmol·L–1: 9.94 ± 8.93, 14.18 ± 14.90, 10.44 ± 14.62) to 3 h postexercise (nmol·L–1: 22.27 ± 13.41, 25.44 ± 11.91, 22.57 ± 15.57) in VPRO, PRO, and PLA, respectively. Contrary to our hypothesis, the drink compositions used did not blunt the postexercise hepcidin response in highly trained athletes.

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