Acute Beetroot Juice Supplementation Does Not Improve Cycling Performance in Normoxia or Moderate Hypoxia

2015 ◽  
Vol 25 (4) ◽  
pp. 359-366 ◽  
Author(s):  
Kristin E. MacLeod ◽  
Sean F. Nugent ◽  
Susan I. Barr ◽  
Michael S. Koehle ◽  
Benjamin C. Sporer ◽  
...  
Keyword(s):  
Steady State ◽  
Power Output ◽  
Time Trial ◽  
Small Sample ◽  
Oxygen Cost ◽  
Beetroot Juice ◽  
Mean Power ◽  
Double Blind ◽  
Moderate Hypoxia ◽  
Mean Power Output

Beetroot juice (BR) has been shown to lower the oxygen cost of exercise in normoxia and may have similar effects in hypoxia. We investigated the effect of BR on steady-state exercise economy and 10-km time trial (TT) performance in normoxia and moderate hypoxia (simulated altitude: ~2500 m). Eleven trained male cyclists (VO2peak ≥ 60 ml·kg-1·min-1) completed four exercise trials. Two hours before exercise, subjects consumed 70 mL BR (~6 mmol nitrate) or placebo (nitrate-depleted BR) in a randomized, double-blind manner. Subjects then completed a 15-min self-selected cycling warm-up, a 15-min steady-state exercise bout at 50% maximum power output, and a 10-km time trial (TT) in either normoxia or hypoxia. Environmental conditions were randomized and single-blind. BR supplementation increased plasma nitrate concentration and fraction of exhaled nitric oxide relative to PL (p < .05 for both comparisons). Economy at 50% power output was similar in hypoxic and normoxic conditions (p > .05), but mean power output was greater in the normoxic TT relative to the hypoxic TT (p < .05). BR did not affect economy, steady-state SpO2, mean power output, or 10-km TT completion time relative to placebo in either normoxia or hypoxia (p > .05 in all comparisons). In conclusion, BR did not lower the oxygen cost of steady-state exercise or improve exercise performance in normoxia or hypoxia in a small sample of well-trained male cyclists.

scholarly journals An Analysis of Variability in Power Output During Indoor and Outdoor Cycling Time Trials

2019 ◽  
Vol 14 (9) ◽  
pp. 1273-1279 ◽  
Author(s):  
Owen Jeffries ◽  
Mark Waldron ◽  
Stephen D. Patterson ◽  
Brook Galna
Keyword(s):  
Power Output ◽  
Time Trial ◽  
Mean Power ◽  
Portable Power ◽  
Output Variability ◽  
Competitive Cyclists ◽  
The Mean ◽  
Mean Power Output ◽  
Testing Protocols ◽  
Indoor And Outdoor

Purpose: Regulation of power output during cycling encompasses the integration of internal and external demands to maximize performance. However, relatively little is known about variation in power output in response to the external demands of outdoor cycling. The authors compared the mean power output and the magnitude of power-output variability and structure during a 20-min time trial performed indoors and outdoors. Methods: Twenty male competitive cyclists ( 60.4 [7.1] mL·kg−1·min−1) performed 2 randomized maximal 20-min time-trial tests: outdoors at a cycle-specific racing circuit and indoors on a laboratory-based electromagnetically braked training ergometer, 7 d apart. Power output was sampled at 1 Hz and collected on the same bike equipped with a portable power meter in both tests. Results: Twenty-minute time-trial performance indoor (280 [44] W) was not different from outdoor (284 [41] W) (P = .256), showing a strong correlation (r = .94; P < .001). Within-persons SD was greater outdoors (69 [21] W) than indoors (33 [10] W) (P < .001). Increased variability was observed across all frequencies in data from outdoor cycling compared with indoors (P < .001) except for the very slowest frequency bin (<0.0033 Hz, P = .930). Conclusions: The findings indicate a greater magnitude of variability in power output during cycling outdoors. This suggests that constraints imposed by the external environment lead to moderate- and high-frequency fluctuations in power output. Therefore, indoor testing protocols should be designed to reflect the external demands of cycling outdoors.

scholarly journals Re-esterified DHA improves ventilatory threshold 2 in competitive amateur cyclists

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Vicente Ávila-Gandía ◽  
Antonio Torregrosa-García ◽  
Antonio J. Luque-Rubia ◽  
María Salud Abellán-Ruiz ◽  
Desirée Victoria-Montesinos ◽  
...  
Keyword(s):  
Power Output ◽  
Ventilatory Threshold ◽  
Heart Rate Recovery ◽  
Recovery Phase ◽  
Lactate Clearance ◽  
Mean Power ◽  
Double Blind ◽  
Cycling Test ◽  
Competitive Cyclists ◽  
Mean Power Output

Abstract Background Fish oils were studied as ergogenic aids in a number of mixed physical trial designs showing promising results. However, the heterogeneous purity of the studied supplements, combined with the variety of physical tests employed call for more studies to confirm these findings, ideally with standardised supplements. Our aim was to test a supplement highly concentrated in DHA (DHA:EPA ratio equal to approximately 8:1) on a maximal cycling test to elucidate performance improvements mainly due to DHA. Methods A double-blind, placebo controlled, randomised balanced, parallel design, in competitive amateur cyclists was employed. They were all male, older than 18 years old, with training routine of 2 to 4 sessions per week lasting at least one hour each. A ramp cycling test to exhaustion with a subsequent 5 min recovery phase was employed before and after treatment to analyse aerobic metabolism and lactate clearance after the bout. After 30 days of supplementation with 975 mg of re-esterified DHA, the thirty-eight cyclist who completed the study were finally included for statistical analysis. Results Mean power output at ventilatory threshold 2 (VT2) improved after DHA supplementation both as absolute (△DHA versus △PLA: 6.33–26.54 Watts; CI 95%) and relative (p=0.006) values, paralleled with higher oxygen consumption at VT2 both for absolute (DHA 2729.4 ±304.5, 3045.9 ±335.0; PLA 2792.3 ±339.5, 2845.5 ±357.1; ml·min−1 baseline versus post p=0.025) and relative values (DHA 36.6 ±5.0, 41.2 ±5.4; PLA 37.2 ±5.7, 38.1 ±5.2; ml·kg−1·min−1 baseline versus post p=0.024). Heart rate recovery rate improved during the recovery phase in the DHA group compared to PLA (p=0.005). Conclusion DHA is capable of improving mean power output at the ventilatory threshold 2 (anaerobic ventilatory threshold) in amateur competitive cyclists. It is unclear if these findings are the result of the specific DHA supplement blend or another factor.

scholarly journals Single and Combined Effects of Beetroot Crystals and Sodium Bicarbonate on 4-km Cycling Time Trial Performance

2017 ◽  
Vol 27 (3) ◽  
pp. 271-278 ◽  
Author(s):  
Marcus J. Callahan ◽  
Evelyn B. Parr ◽  
John A. Hawley ◽  
Louise M. Burke
Keyword(s):  
Sodium Bicarbonate ◽  
Latin Square ◽  
Time Trial ◽  
Cycle Ergometer ◽  
Combined Effects ◽  
Beetroot Juice ◽  
Mean Power ◽  
Cycling Time Trial ◽  
Plasma Nitrite ◽  
Mean Power Output

When ingested alone, beetroot juice and sodium bicarbonate are ergogenic for high-intensity exercise performance. This study sought to determine the independent and combined effects of these supplements. Eight endurance trained (VO2max 65 mL·kg·min-1) male cyclists completed four × 4-km time trials (TT) in a doubleblind Latin square design supplementing with beetroot crystals (BC) for 3 days (15 g·day-1 + 15 g 1 h before TT, containing 300 mg nitrate per 15 g), bicarbonate (Bi 0.3 g·kg-1 body mass [BM] in 5 doses every 15 min from 2.5 h before TT); BC+Bi or placebo (PLA). Subjects completed TTs on a Velotron cycle ergometer under standardized laboratory conditions. Plasma nitrite concentrations were significantly elevated only in the BC+Bi trial before the TT (1520 ± 786 nmol·L-1) compared with baseline (665 ± 535 nmol·L-1, p = .02) and the Bi and PLA conditions (Bi: 593 ± 203 nmol·L-1, p < .01; PLA: 543 ± 369 nmol·L-1, p < .01). Plasma nitrite concentrations were not elevated in the BC trial before the TT (1102 ± 218 nmol·L-1) compared with baseline (975 ± 607 nmol·L-1, p > .05). Blood bicarbonate concentrations were increased in the BC+Bi and Bi trials before the TT (BC+Bi: 30.9 ± 2.8 mmol·L-1; Bi: 31.7 ± 1.1 mmol·L-1). There were no differences in mean power output (386–394 W) or the time taken to complete the TT (335.8–338.1 s) between any conditions. Under the conditions of this study, supplementation was not ergogenic for 4-km TT performance.

N-acetylcysteine alters substrate metabolism during high-intensity cycle exercise in well-trained humans

2013 ◽  
Vol 38 (12) ◽  
pp. 1217-1227 ◽  
Author(s):  
Adam J. Trewin ◽  
Aaron C. Petersen ◽  
Francois Billaut ◽  
Leon R. McQuade ◽  
Bernie V. McInerney ◽  
...  
Keyword(s):  
Power Output ◽  
High Intensity ◽  
Repeated Measures ◽  
Vastus Lateralis ◽  
Venous Blood ◽  
Time Trial ◽  
Peak Power Output ◽  
Mean Power ◽  
Double Blind ◽  
Substrate Metabolism

We investigated the effects of N-acetylcysteine (NAC) on metabolism during fixed work rate high-intensity interval exercise (HIIE) and self-paced 10-min time-trial (TT10) performance. Nine well-trained male cyclists (V̇O2peak, 69.4 ± 5.8 mL·kg−1·min−1; peak power output (PPO), 385 ± 43 W; mean ± SD) participated in a double-blind, repeated-measures, randomised crossover trial. Two trials (NAC supplementation and placebo) were performed 7 days apart consisting of 6 × 5 min HIIE bouts at 82% PPO (316 ± 40 W) separated by 1 min at 100 W, and then after 2 min of recovery at 100 W, TT10 was performed. Expired gases, venous blood, and electromyographic (EMG) data were collected. NAC did not influence blood glutathione but decreased lipid peroxidation compared with the placebo (P < 0.05). Fat oxidation was elevated with NAC compared with the placebo during HIIE bouts 5 and 6 (9.9 ± 8.9 vs. 3.9 ± 4.8 μmol·kg−1·min−1; P < 0.05), as was blood glucose throughout HIIE (4.3 ± 0.6 vs. 3.8 ± 0.6 mmol·L−1; P < 0.05). Blood lactate was lower with NAC after TT10 (3.3 ± 1.3 vs. 4.2 ± 1.3 mmol·L−1; P < 0.05). Median EMG frequency of the vastus lateralis was lower with NAC during HIIE (79 ± 10 vs. 85 ± 10 Hz; P < 0.05), but not TT10 (82 ± 11 Hz). Finally, NAC decreased mean power output 4.9% ± 6.6% (effect size = –0.3 ± 0.4, mean ± 90% CI) during TT10 (305 ± 57 W vs. 319 ± 45 W). These data suggest that NAC alters substrate metabolism and muscle fibre type recruitment during HIIE, which is detrimental to time-trial performance.

Physiological Profile of an Uphill Time Trial in Elite Cyclists

2018 ◽  
Vol 13 (3) ◽  
pp. 268-273 ◽  
Author(s):  
Ana B. Peinado ◽  
Nuria Romero-Parra ◽  
Miguel A. Rojo-Tirado ◽  
Rocío Cupeiro ◽  
Javier Butragueño ◽  
...  
Keyword(s):  
Power Output ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Time Trial ◽  
Cycling Performance ◽  
Mean Power ◽  
Road Cycling ◽  
And Performance ◽  
Mean Power Output ◽  
Elite Cyclists

Context: While a number of studies have researched road-cycling performance, few have attempted to investigate the physiological response in field conditions. Purpose: To describe the physiological and performance profile of an uphill time trial (TT) frequently used in cycling competitions. Methods: Fourteen elite road cyclists (mean ± SD age 25 ± 6 y, height 174 ± 4.2 cm, body mass 64.4 ± 6.1 kg, fat mass 7.48% ± 2.82%) performed a graded exercise test to exhaustion to determine maximal parameters. They then completed a field-based uphill TT in a 9.2-km first-category mountain pass with a 7.1% slope. Oxygen uptake (VO2), power output, heart rate (HR), lactate concentration, and perceived-exertion variables were measured throughout the field-based test. Results: During the uphill TT, mean power output and velocity were 302 ± 7 W (4.2 ± 0.1 W/kg) and 18.7 ± 1.6 km/h, respectively. Mean VO2 and HR were 61.6 ± 2.0 mL · kg−1 · min−1 and 178 ± 2 beats/min, respectively. Values were significantly affected by the 1st, 2nd, 6th, and final kilometers (P < .05). Lactate concentration and perceived exertion were 10.87 ± 1.12 mmol/L and 19.1 ± 0.1, respectively, at the end of the test, being significantly different from baseline measures. Conclusion: The studied uphill TT is performed at 90% of maximum HR and VO2 and 70% of maximum power output. To the authors’ knowledge, this is the first study assessing cardiorespiratory parameters combined with measures of performance, perceived exertion, and biochemical variables during a field-based uphill TT in elite cyclists.

scholarly journals The Influence of Elliptical Chainrings on 10 km Cycling Time Trial Performance

2010 ◽  
Vol 5 (4) ◽  
pp. 459-468 ◽  
Author(s):  
Jeremiah J. Peiffer ◽  
Chris R. Abbiss
Keyword(s):  
Heart Rate ◽  
Power Output ◽  
Time Trial ◽  
Total Power ◽  
Mean Power ◽  
Actual Performance ◽  
Cycling Time Trial ◽  
And Performance ◽  
Mean Power Output ◽  
Cycling Time

The use of elliptical chainrings (also called chainwheels or sprockets) has gained considerable interest in the amateur and professional cycling community. Nevertheless, we are unaware of any scientific studies that have examined the performance benefits of using elliptical chainrings during an actual performance trial. Therefore, this study examined the influence of elliptical chainring use on physiological and performance parameters during a 10 km cycling time trial. Nine male cyclists completed, in a counterbalanced order, three 10 km cycling time trials using either a standard chainring or an elliptical chainring at two distinct settings. An attempt was made to blind the cyclists to the type of chainring used until the completion of the study. During the 10 km time trial, power output and heart rate were recorded at a frequency of 1 Hz and RPE was measured at 3, 6, and 8.5 km. Total power output was not different (P = .40) between the circular (340 ± 30 W) or either elliptical chainring condition (342 ± 29 W and 341 ± 31 W). Similarly, no differences (P = .73) in 2 km mean power output were observed between conditions. Further, no differences in RPE were observed between conditions measured at 3, 6, and 8.5 km. Heart rate was significantly greater (P = .02) using the less aggressive elliptical setting (174 ± 10 bpm) compared with the circular setting (171 ± 9 bpm). Elliptical chainrings do not appear to provide a performance benefit over traditional circular chainrings during a mid-distance time trial.

scholarly journals Acute Beetroot Juice Supplementation Attenuates Morning-Associated Decrements in Supramaximal Exercise Performance in Trained Sprinters

2021 ◽  
Vol 18 (2) ◽  
pp. 412
Author(s):  
Amanda M. Dumar ◽  
Anna F. Huntington ◽  
Rebecca R. Rogers ◽  
Thomas J. Kopec ◽  
Tyler D. Williams ◽  
...  
Keyword(s):  
Power Output ◽  
Perceived Exertion ◽  
National Collegiate Athletic Association ◽  
Anaerobic Capacity ◽  
Total Work ◽  
Beetroot Juice ◽  
Mean Power ◽  
Diurnal Fluctuations ◽  
Double Blinded ◽  
Mean Power Output

Diurnal fluctuations in power output have been well established with power loss typically occurring in morning (AM) times. Beetroot juice (BRJ) is a source of dietary nitrate that possess ergogenic properties, but it is unknown if ingestion can mitigate performance decrements in the morning. The purpose of this study was to examine the effects of acute BRJ supplementation on diurnal fluctuations in anaerobic performance in trained sprinters. Male Division 1 National Collegiate Athletic Association (NCAA) sprinters (n = 10) participated. In a double-blinded crossover study design, participants completed three counterbalanced exercise trials under different conditions: Morning–placebo (8:00 HR, AM-PL), Morning–BRJ (8:00 HR, AM-BRJ), and Afternoon–no supplement (15:00 HR, PM). For each trial, participants completed 3 × 15 s Wingate anaerobic tests separated by 2 min of rest. Each trial was separated by a 72 h washout period. Mean power output (p = 0.043), anaerobic capacity (p = 0.023), and total work (p = 0.026) were significantly lower with the AM-PL condition compared to PM. However, BRJ supplementation prevented AM losses of mean power output (p = 0.994), anaerobic capacity (p = 0.941), and total work (p = 0.933) in the AM-BRJ compared to the PM condition. Rate of perceived exertion was not significantly different between any conditions (p = 0.516). Heart rate was significantly lower during the AM-BRJ condition compared to AM-PL (p = 0.030) and PM (p < 0.001). Findings suggest anaerobic capacity suffers during AM versus PM times in trained sprinters, but BRJ ingestion abolishes AM-associated decrements in performance.

scholarly journals Influence of Trehalose Mouth Rinse on Anaerobic and Aerobic Exercise Performance

2020 ◽  
Vol 15 (11) ◽  
pp. 1934578X2096959
Author(s):  
Yoshio Suzuki ◽  
Kotaro Sato ◽  
Norie Arai ◽  
Shin Endo
Keyword(s):  
Exercise Performance ◽  
Power Output ◽  
Peak Power ◽  
Mouth Rinse ◽  
Distance Runners ◽  
Mean Power ◽  
Double Blind ◽  
Endurance Tests ◽  
Mean Power Output ◽  
Second Peak

Trehalose is a disaccharide consisting of 2 glucose units linked in an alpha 1,1-glycosidic bond. Pre-exercise trehalose ingestion enhances exercise performance within 30 minutes. Enhanced performance was hypothesized to be due to a mouth rinse effect. A 3-arm double-blind crossover trial was conducted to test this hypothesis. Ten healthy male collegiate distance runners rinsed their mouths with either trehalose (6% w/v) or maltose (6% w/v) or acesulfame potassium (0.04 mg/mL) for 5 seconds and then performed an exercise assessment composed of 6-second peak power and endurance tests. Trehalose induced the highest mean power output ( P < .01) in peak power tests. In the endurance test, trehalose consistently showed higher mean power output than maltose. The 3 test drinks displayed indistinguishable sweetness and were expected to activate receptors for sweetness (T1R2-T1R3) with the same intensity. Trehalose activates taste receptors T1R1-T1R3, T1R3-T1R3 homodimer, and T1R2-T1R3, whereas sucrose activates only T1R2-T1R3. Therefore, a difference in mouth rinse effect might be due to a specific receptor in the oral cavity that recognizes differences between trehalose and maltose.

No Improvement of Repeated-Sprint Performance With Dietary Nitrate

2014 ◽  
Vol 9 (5) ◽  
pp. 845-850 ◽  
Author(s):  
Kristy Martin ◽  
Disa Smee ◽  
Kevin G. Thompson ◽  
Ben Rattray
Keyword(s):  
Power Output ◽  
High Intensity ◽  
Cycle Ergometer ◽  
Sprint Performance ◽  
Mean Power ◽  
Double Blind ◽  
Dietary Nitrate ◽  
Repeated Sprint ◽  
Nitrate Supplementation ◽  
Mean Power Output

Purpose:Nitrate supplementation improves endurance exercise and single bouts of high-intensity activity, but its effect on repeated sprints is unclear. This study is the first to investigate the effects of acute dietary nitrate supplementation during a high-intensity intermittent-sprint test to exhaustion.Methods:Team-sport athletes (9 male, age 22.3 ± 2.1 y, VO2max 57.4 ± 8.5 mL · kg−1 · min−1; 7 female, age 20.7 ± 1.3 y, VO2max 47.2 ± 8.5 mL · kg−1 · min−1) were assigned to a double-blind, randomized, crossover design. Participants consumed 70 mL of concentrated beetroot juice containing a minimum of 0.3 g of nitrate (NT) or 70 mL of placebo (PL) 2 h before a repeated-sprint protocol involving repeated 8-s sprints with 30-s recovery on a cycle ergometer to exhaustion.Results:Fewer sprints (NT = 13 ± 5 vs PL = 15 ± 6, P = .005, d = 0.41) and less total work (NT = 49.2 ± 24.2 kJ vs PL = 57.8 ± 34.0 kJ, P = .027, d = 0.3) were completed in NT relative to PL. However there was no difference in overall mean power output or the mean power output for each individual 8-s sprint.Conclusions:These findings suggest that dietary nitrate is not beneficial for improving repeated-sprint performance, at least when such sprints are near-maximal and frequent in nature. The lack of an effect of nitrate at near-maximal oxygen uptake supports the suggestion that at greater exercise intensities nitrate does not have an ergogenic effect.

scholarly journals Validity of PowerTap P1 Pedals during Laboratory-Based Cycling Time Trial Performance

Sports ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 92 ◽  
Author(s):  
Chris Whittle ◽  
Neal Smith ◽  
Simon Jobson
Keyword(s):  
Power Output ◽  
Time Trial ◽  
Mean Power ◽  
Cycling Time Trial ◽  
Valid Measurement ◽  
Measuring Devices ◽  
Mean Power Output ◽  
Maximum Minimum ◽  
Cycling Time ◽  
Trial Performance

The use of mobile power measuring devices has become widespread within cycling, with a number of manufacturers now offering power measuring pedals. This study aimed to investigate the validity of PowerTap P1 pedals by comparing them with the previously validated Wattbike ergometer. Ten trained cyclists performed three simulated 10-mile (16-km) time trials on a Wattbike, while using PowerTap P1 pedals. There were no statistically significant differences (p > 0.05) between PowerTap P1 pedals and a Wattbike for maximum, minimum, and mean power output, or for maximum, minimum, and mean cadence. There were good to excellent levels of agreement between the PowerTap P1 pedals and Wattbike (ICC > 0.8) for all measured variables except minimum cadence (ICC = 0.619). This suggests that PowerTap P1 pedals provide a valid measurement of power output.

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