scholarly journals The Effect of 1,3-Butanediol on Cycling Time-Trial Performance

2019 ◽  
Vol 29 (5) ◽  
pp. 466-473 ◽  
Author(s):  
David M. Shaw ◽  
Fabrice Merien ◽  
Andrea Braakhuis ◽  
Daniel Plews ◽  
Paul Laursen ◽  
...  
Keyword(s):  
Steady State ◽  
Body Mass ◽  
Repeated Measures ◽  
Average Power ◽  
Gastrointestinal Symptoms ◽  
Time Trial ◽  
Endurance Performance ◽  
Carbon Dioxide Production ◽  
Serum Glucose ◽  
Cycling Time Trial

This study investigated the effect of the racemic β-hydroxybutyrate (βHB) precursor, R,S-1,3-butanediol (BD), on time-trial (TT) performance and tolerability. A repeated-measures, randomized, crossover study was conducted in nine trained male cyclists (age, 26.7 ± 5.2 years; body mass, 69.6 ± 8.4 kg; height, 1.82 ± 0.09 m; body mass index, 21.2 ± 1.5 kg/m2; VO2peak,63.9 ± 2.5 ml·kg−1·min−1; Wmax, 389.3 ± 50.4 W). Participants ingested 0.35 g/kg of BD or placebo 30 min before and 60 min during 85 min of steady-state exercise, which preceded a ∼25- to 35-min TT (i.e., 7 kJ/kg). The ingestion of BD increased blood D-βHB concentration throughout exercise (0.44–0.79 mmol/L) compared with placebo (0.11–0.16 mmol/L; all p < .001), which peaked 1 hr following the TT (1.38 ± 0.35 vs. 0.34 ± 0.24 mmol/L; p < .001). Serum glucose and blood lactate concentrations were not different between trials (all p > .05). BD ingestion increased oxygen consumption and carbon dioxide production after 20 min of steady-state exercise (p = .002 and p = .032, respectively); however, no further effects on cardiorespiratory parameters were observed. Within the BD trial, moderate to severe gastrointestinal symptoms were reported in five participants, and low levels of dizziness, nausea, and euphoria were reported in two participants. However, this had no effect on TT duration (placebo, 28.5 ± 3.6 min; BD, 28.7 ± 3.2 min; p = .62) and average power output (placebo, 290.1 ± 53.7 W; BD, 286.4 ± 45.9 W; p = .50). These results suggest that BD has no benefit for endurance performance.

scholarly journals Caffeine Ingestion Does Not Alter Performance during a 100-km Cycling Time-Trial Performance

2002 ◽  
Vol 12 (4) ◽  
pp. 438-452 ◽  
Author(s):  
Angus M. Hunter ◽  
Allan St ◽  
Clair Gibson ◽  
Malcolm Collins ◽  
Mike Lambert ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Average Power ◽  
Time Trial ◽  
Peripheral Fatigue ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Caffeine Ingestion ◽  
Cycling Time Trial ◽  
Time To Completion ◽  
Cycling Time

This study analyzed the effect of caffeine ingestion on performance during a repeated-measures, 100-km, laboratory cycling time trial that included bouts of 1- and 4-km high intensity epochs (HIE). Eight highly trained cyclists participated in 3 separate trials—placebo ingestion before exercise with a placebo carbohydrate solution and placebo tablets during exercise (Pl), or placebo ingestion before exercise with a 7% carbohydrate drink and placebo tablets during exercise (Cho), or caffeine tablet ingestion before and during exercise with 7% carbohydrate (Caf). Placebo (twice) or 6 mg · kg−1 caffeine was ingested 60 min prior to starting 1 of the 3 cycling trials, during which subjects ingested either additional placebos or a caffeine maintenance dose of 0.33 mg · kg−1 every 15 min to trial completion. The 100-km time trial consisted of five 1-km HIE after 10, 32, 52, 72, and 99 km, as well as four 4-km HIE after 20, 40, 60, and 80 km. Subjects were instructed to complete the time trial and all HIE as fast as possible. Plasma (caffeine) was significantly higher during Caf (0.43 ± 0.56 and 1.11 ± 1.78 mM pre vs. post Pl; and 47.32 ± 12.01 and 72.43 ± 29.08 mM pre vs. post Caf). Average power, HIE time to completion, and 100-km time to completion were not different between trials. Mean heart rates during both the 1-km HIE (184.0 ± 9.8 Caf; 177.0 ± 5.8 Pl; 177.4 ± 8.9 Cho) and 4-km HIE (181.7 ± 5.7 Caf; 174.3 ± 7.2 Pl; 175.6 ± 7.6 Cho; p < .05) was higher in Caf than in the other groups. No significant differences were found between groups for either EMG amplitude (IEMG) or mean power frequency spectrum (MPFS). IEMG activity and performance were not different between groups but were both higher in the 1-km HIE, indicating the absence of peripheral fatigue and the presence of a centrally-regulated pacing strategy that is not altered by caffeine ingestion. Caffeine may be without ergogenic benefit during endurance exercise in which the athlete begins exercise with a defined, predetermined goal measured as speed or distance.

scholarly journals Effect of Warm-Up and Sodium Bicarbonate Ingestion on 4-km Cycling Time-Trial Performance

2020 ◽  
pp. 1-7
Author(s):  
William H. Gurton ◽  
Steve H. Faulkner ◽  
Ruth M. James
Keyword(s):  
Sodium Bicarbonate ◽  
Blood Lactate ◽  
Body Mass ◽  
Repeated Measures ◽  
Lactate Concentration ◽  
Time Trial ◽  
Placebo Control ◽  
Warm Up ◽  
Cycling Time Trial ◽  
Cycling Time

Purpose: To examine whether an ecologically valid, intermittent, sprint-based warm-up strategy impacted the ergogenic capacity of individualized sodium bicarbonate (NaHCO3) ingestion on 4-km cycling time-trial (TT) performance. Methods: A total of 8 male cyclists attended 6 laboratory visits for familiarization, determination of time to peak blood bicarbonate, and 4 × 4-km cycling TTs. Experimental beverages were administered doubleblind. Treatments were conducted in a block-randomized, crossover order: intermittent warm-up + NaHCO3 (IWSB), intermittent warm-up + placebo, control warm-up + NaHCO3 (CWSB), and control warm-up + placebo (CWP). The intermittent warm-up comprised exercise corresponding to lactate threshold (5 min at 50%, 2 min at 60%, 2 min at 80%, 1 min at 100%, and 2 min at 50%) and 3 × 10-second maximal sprints. The control warm-up comprised 16.5 minutes cycling at 150 W. Participants ingested 0.3 g·kg body mass−1 NaHCO3 or 0.03 g·kg body mass−1 sodium chloride (placebo) in 5 mL·kg body mass−1 fluid (3:2, water and sugar-free orange squash). Paired t tests were conducted for TT performance. Hematological data (blood bicarbonate and blood lactate) and gastrointestinal discomfort were analyzed using repeated-measures analysis of variance. Results: Performance was faster for CWSB versus IWSB (5.0 [6.1] s; P = .052) and CWP (5.8 [6.0] s; P = .03). Pre-TT bicarbonate concentration was elevated for CWSB versus IWSB (+9.3 mmol·L−1; P < .001) and CWP (+7.1 mmol·L−1; P < .001). Post-TT blood lactate concentration was elevated for CWSB versus CWP (+2.52 mmol·L−1; P = .022). Belching was exacerbated pre-warm-up for IWSB versus intermittent warm-up +placebo (P = .046) and CWP (P = .027). Conclusion: An intermittent, sprint-based warm-up mitigated the ergogenic benefits of NaHCO3 ingestion on 4-km cycling TT performance.

Cycling Time Trial Performance May Be Impaired by Whey Protein and L-Alanine Intake During Prolonged Exercise

2014 ◽  
Vol 24 (5) ◽  
pp. 507-515 ◽  
Author(s):  
Adam B. Schroer ◽  
Michael J. Saunders ◽  
Daniel A. Baur ◽  
Christopher J. Womack ◽  
Nicholas D. Luden
Keyword(s):  
Time Trial ◽  
Endurance Performance ◽  
Constant Load ◽  
Protein Amino Acid ◽  
Cycling Time Trial ◽  
Glucose Levels ◽  
Load Cycling ◽  
Additional Protein ◽  
Response To Exercise ◽  
The Impact

Previous studies reported that adding protein (PRO) to carbohydrate (CHO) solutions enhances endurance performance. The ergogenic effect may be a function of additional protein/amino acid calories, but this has not been examined. In addition, although supplemental L-alanine (ALA) is readily oxidized during exercise, the subsequent impact on metabolism and prolonged endurance performance is unknown. The purpose of this investigation was to independently gauge the impact of whey PRO hydrolysate and ALA supplementation on performance and various physiological parameters. Eight cyclists (age: 22.3 ± 5.6 yr, weight: 70.0 ± 8.0 kg, VO2max: 59.4 ± 4.9 ml·kg−1·min−1) performed 120 min of constant-load cycling (55% of peak power) followed by a 30-km time trial (TT) under placebo (PLA), PRO, and ALA conditions. Magnitude-based qualitative inferences were applied to evaluate treatment differences and data are presented as percent difference between treatments ± 90% confidence limit. Both ALA (–2.1 ± 2.7%) and PRO intake (–2.1 ± 2.2%) possibly harmed performance compared with PLA. Of interest, heart rate was possibly lower with ALA than PLA at 20– (–2.7 ± 3.4%) and 120-min (–1.7 ± 2.9%) of constant-load cycling and the serum interleukin-6 (IL-6) response to 120 min of cycling was likely attenuated with PRO compared with PLA (PLA, 6.6 ± 3.7 fold vs. PRO, 2.9 ± 1.8 fold). In addition, blood glucose levels were lower with PRO than PLA at 20– (–8.8 ± 2.3%; very likely) and 120-min (–4.9 ± 4.6%; likely) of constant-load cycling. Although ALA intake appears to lower HR and PRO ingestion dampens the IL-6 response to exercise, the ingestion of PRO (without CHO) or ALA does not enhance, and may actually impair, performance following prolonged cycling.

scholarly journals The Effects of Inhaled Terbutaline on 3-km Running Time-Trial Performance

2019 ◽  
Vol 14 (6) ◽  
pp. 822-828 ◽  
Author(s):  
John Molphy ◽  
John W. Dickinson ◽  
Neil J. Chester ◽  
Mike Loosemore ◽  
Gregory Whyte
Keyword(s):  
Repeated Measures ◽  
Time Trial ◽  
Endurance Performance ◽  
Forced Expiratory Volume ◽  
Concentration Data ◽  
Running Performance ◽  
Running Time ◽  
Time Trial Performance ◽  
Repeated Measures Design ◽  
Trial Performance

Terbutaline is a prohibited drug except for athletes with a therapeutic use exemption certificate; terbutaline’s effects on endurance performance are relatively unknown. Purpose: To investigate the effects of 2 therapeutic (2 and 4 mg) inhaled doses of terbutaline on 3-km running time-trial performance. Methods: A total of 8 men (age 24.3 [2.4] y; weight 77.6 [8] kg; and height 179.5 [4.3] cm) and 8 women (age 22.4 [3] y; weight 58.6 [6] kg; and height 163 [9.2] cm) free from respiratory disease and illness provided written informed consent. Participants completed 3-km running time trials on a nonmotorized treadmill on 3 separate occasions following placebo and 2- and 4-mg inhaled terbutaline in a single-blind, repeated-measures design. Urine samples (15 min postexercise) were analyzed for terbutaline concentration. Data were analyzed using 1-way repeated-measures analysis of variance, and significance was set at P < .05 for all analyses. Results: No differences were observed for completion times (1103 [201] s, 1106 [195] s, 1098 [165] s; P = .913) for the placebo or 2- and 4-mg inhaled trials, respectively. Lactate values were higher (P = .02) after 4 mg terbutaline (10.7 [2.3] mmol·L−1) vs placebo (8.9 [1.8] mmol·L−1). Values of forced expiratory volume in the first second of expiration (FEV1) were greater after inhalation of 2 mg (5.08 [0.2]; P = .01) and 4 mg terbutaline (5.07 [0.2]; P = .02) compared with placebo (4.83 [0.5] L) postinhalation. Urinary terbutaline concentrations were mean 306 (288) ng·mL−1 and 435 (410) ng·mL−1 (P = .2) and peak 956 ng·mL−1 and 1244 ng·mL−1 after 2 and 4 mg inhaled terbutaline, respectively. No differences were observed between the male and female participants. Conclusions: Therapeutic dosing of terbutaline does not lead to an improvement in 3-km running performance despite significantly increased FEV1. The findings suggest that athletes using inhaled terbutaline at high therapeutic doses to treat asthma will not gain an ergogenic advantage during 3-km running performance.

Cycling Time Trial Performance 4 Hours After Glycogen-Lowering Exercise Is Similarly Enhanced by Recovery Nondairy Chocolate Beverages Versus Chocolate Milk

2016 ◽  
Vol 26 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Adam U. Upshaw ◽  
Tiffany S. Wong ◽  
Arash Bandegan ◽  
Peter W.R. Lemon
Keyword(s):  
Repeated Measures ◽  
Time Trial ◽  
Chocolate Milk ◽  
Double Blind ◽  
Time Trial Performance ◽  
Cycling Time Trial ◽  
Repeated Measures Design ◽  
Dairy Milk ◽  
Cycling Time ◽  
Trial Performance

Postexercise chocolate milk ingestion has been shown to enhance both glycogen resynthesis and subsequent exercise performance. To assess whether nondairy chocolate beverage ingestion post–glycogen-lowering exercise can enhance 20-km cycling time trial performance 4 hr later, eight healthy trained male cyclists (21.8 ± 2.3y, VO2max = 61.2 ± 1.4 ml·kg-1·min-1; M ± SD) completed a series of intense cycling intervals designed to lower muscle glycogen (Jentjens & Jeukendrup, 2003) followed by 4 hr of recovery and a subsequent 20-km cycling time trial. During the first 2 hr of recovery, participants ingested chocolate dairy milk (DAIRYCHOC), chocolate soy beverage (SOYCHOC), chocolate hemp beverage (HEMPCHOC), low-fat dairy milk (MILK), or a low-energy artificially sweetened, flavored beverage (PLACEBO) at 30-min intervals in a double-blind, counterbalanced repeated-measures design. All drinks, except the PLACEBO (247 kJ) were isoenergetic (2,107 kJ), and all chocolate-flavored drinks provided 1-g CHO·kg body mass-1·h-1. Fluid intake across treatments was equalized (2,262 ± 148 ml) by ingesting appropriate quantities of water based on drink intake. The CHO:PRO ratio was 4:1, 1.5:1, 4:1, and 6:1 for DAIRYCHOC, MILK, SOYCHOC, and HEMPCHOC, respectively. One-way analysis of variance with repeated measures showed time trial performance (DAIRYCHOC = 34.58 ± 2.5 min, SOYCHOC = 34.83 ± 2.2 min, HEMPCHOC = 34.88 ± 1.1 min, MILK = 34.47 ± 1.7 min) was enhanced similarly vs PLACEBO (37.85 ± 2.1) for all treatments (p = .019) These data suggest that postexercise macronutrient and total energy intake are more important for same-day 20-km cycling time trial performance after glycogen-lowering exercise than protein type or protein-to-carbohydrate ratio.

scholarly journals Gastrointestinal Symptoms Related to Potato Ingestion During Cycling in Trained Athletes (P23-012-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Susannah Scaroni ◽  
Amadeo Salvador ◽  
Colleen McKenna ◽  
Rafael Alamilla ◽  
Isabel Martinez ◽  
...  
Keyword(s):  
Perceived Exertion ◽  
Mixed Model ◽  
Gastrointestinal Symptoms ◽  
Time Trial ◽  
Endurance Performance ◽  
Rating Of Perceived Exertion ◽  
Random Factor ◽  
Mixed Model Analysis ◽  
Gi Symptoms ◽  
Significant Difference

Abstract Objectives Carbohydrate (CHO) ingestion is an established nutritional strategy to improve endurance performance, yet currently available products may contribute to gastrointestinal (GI) distress. Potatoes have a high-glycemic index, indicating that their CHO content is readily available. We aimed to compare the effects of ingesting potato purée (POT), commercial CHO gel (GEL), or a control (water, CTL) during cycling on GI Symptoms and affective indices in trained athletes. Methods In a randomized crossover study, twelve trained cyclists (9 M and 3F; 30.5 ± 8.7y; 70.6 ± 7.6 kg; 1.70 ± 7 cm; 60.7 ± 8.9 mL/kg/min) completed a 2 h cycling challenge (60–85%VO2max) followed by a 6 kJ/kg time trial. Cyclists were randomly assigned to consume POT, GEL, or CTL during the challenge. Rating of perceived exertion (RPE), GI symptoms, and affective responses (Feeling Scale −5/+5) were collected throughout the challenge via visual analog scales. Differences between treatments were assessed by mixed model analysis of variance using time and condition as a fixed factor and subject as a random factor. All data represent mean ± standard deviation. Results RPE was not different between POT, GEL, or CTL condition at the end of the cycling challenge (POT: 17 ± 1; GEL: 17 ± 1, CTL: 18 ± 1, P > 0.05). Higher GI symptoms (P < 0.01) were observed at the end of the challenge during POT condition (15 ± 3%) when compared to GEL (8 ± 3%) and CTL (7 ± 3%), with no significant difference in these symptoms prior to this time. FS response significantly increased (P = 0.04) during POT trial (2 ± 2) compared to GEL (0 ± 0.2) and CTL (0 ± 2) conditions at end of the challenge. Conclusions While POT ingestion resulted in greater GI distressed compared to CHO gel, cyclists perceived the exertion to be similar and even reported feeling more pleasant after POT ingestion in endurance exercise. Funding Sources Alliance for Potato Research and Education.

Effect of different protocols of caffeine intake on metabolism and endurance performance

2002 ◽  
Vol 93 (3) ◽  
pp. 990-999 ◽  
Author(s):  
Gregory R. Cox ◽  
Ben Desbrow ◽  
Paul G. Montgomery ◽  
Megan E. Anderson ◽  
Clinton R. Bruce ◽  
...  
Keyword(s):  
Steady State ◽  
Confidence Interval ◽  
Time Trial ◽  
Endurance Performance ◽  
Caffeine Intake ◽  
Sports Drink ◽  
Competitive Athletes

Competitive athletes completed two studies of 2-h steady-state (SS) cycling at 70% peak O2uptake followed by 7 kJ/kg time trial (TT) with carbohydrate (CHO) intake before (2 g/kg) and during (6% CHO drink) exercise. In Study A, 12 subjects received either 6 mg/kg caffeine 1 h preexercise (Precaf), 6 × 1 mg/kg caffeine every 20 min throughout SS (Durcaf), 2 × 5 ml/kg Coca-Cola between 100 and 120 min SS and during TT (Coke), or placebo. Improvements in TT were as follows: Precaf, 3.4% (0.2–6.5%, 95% confidence interval); Durcaf, 3.1% (−0.1–6.5%); and Coke, 3.1% (−0.2–6.2%). In Study B, eight subjects received 3 × 5 ml/kg of different cola drinks during the last 40 min of SS and TT: decaffeinated, 6% CHO (control); caffeinated, 6% CHO; decaffeinated, 11% CHO; and caffeinated, 11% CHO (Coke). Coke enhanced TT by 3.3% (0.8–5.9%), with all trials showing 2.2% TT enhancement (0.5–3.8%; P < 0.05) due to caffeine. Overall, 1) 6 mg/kg caffeine enhanced TT performance independent of timing of intake and 2) replacing sports drink with Coca-Cola during the latter stages of exercise was equally effective in enhancing endurance performance, primarily due to low intake of caffeine (∼1.5 mg/kg).

Improved Cycling Time-Trial Performance after Ingestion of a Caffeine Energy Drink

2009 ◽  
Vol 19 (1) ◽  
pp. 61-78 ◽  
Author(s):  
John L. Ivy ◽  
Lynne Kammer ◽  
Zhenping Ding ◽  
Bei Wang ◽  
Jeffrey R. Bernard ◽  
...  
Keyword(s):  
Perceived Exertion ◽  
Time Trial ◽  
Endurance Performance ◽  
Energy Drink ◽  
Rating Of Perceived Exertion ◽  
Double Blind ◽  
Time Trial Performance ◽  
Cycling Time Trial ◽  
Cycling Time ◽  
Trial Performance

Context:Not all athletic competitions lend themselves to supplementation during the actual event, underscoring the importance of preexercise supplementation to extend endurance and improve exercise performance. Energy drinks are composed of ingredients that have been found to increase endurance and improve physical performance.Purpose:The purpose of the study was to investigate the effects of a commercially available energy drink, ingested before exercise, on endurance performance.Methods:The study was a double-blind, randomized, crossover design. After a 12-hr fast, 6 male and 6 female trained cyclists (mean age 27.3 ± 1.7 yr, mass 68.9 ± 3.2 kg, and VO2 54.9 ± 2.3 ml · kg–1 · min–1) consumed 500 ml of either flavored placebo or Red Bull Energy Drink (ED; 2.0 g taurine, 1.2 g glucuronolactone, 160 mg caffeine, 54 g carbohydrate, 40 mg niacin, 10 mg pantothenic acid, 10 mg vitamin B6, and 10 μg vitamin B12) 40 min before a simulated cycling time trial. Performance was measured as time to complete a standardized amount of work equal to 1 hr of cycling at 70% Wmax.Results:Performance improved with ED compared with placebo (3,690 ± 64 s vs. 3,874 ± 93 s, p < .01), but there was no difference in rating of perceived exertion between treatments. β-Endorphin levels increased during exercise, with the increase for ED approaching significance over placebo (p = .10). Substrate utilization, as measured by open-circuit spirometry, did not differ between treatments.Conclusion:These results demonstrate that consuming a commercially available ED before exercise can improve endurance performance and that this improvement might be in part the result of increased effort without a concomitant increase in perceived exertion.

scholarly journals Caffeine but not acetaminophen increases 4-km cycling time-trial performance

2019 ◽  
Author(s):  
Fabiano Tomazini ◽  
Ana Carla S. Mariano ◽  
Victor A. Andrade-Souza ◽  
Viviane C. Sebben ◽  
Carlos A. B. de Maria ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Body Mass ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Time Trial ◽  
Rating Of Perceived Exertion ◽  
Plasma Lactate ◽  
Double Blind ◽  
Cycling Time Trial ◽  
Cycling Time

AbstractAcetaminophen has been combined with caffeine for therapeutic purpose, but the effect of co-ingestion of acetaminophen and caffeine on exercise performance has not been investigated. The aim of this study was to determine the effect of isolated and combined ingestion of caffeine and acetaminophen on performance during a 4-km cycling time-trial. In a double-blind, crossover design, eleven men, accustomed to cycling recreationally, completed a 4-km cycling time-trial one hour after the ingestion of cellulose (PLA), acetaminophen (20 mg·kg−1body mass, ACT), caffeine (5 mg·kg−1body mass, CAF) or combined acetaminophen and caffeine (20 and 5 mg·kg−1body mass, respectively, ACTCAF). The perception of pain and rating of perceived exertion were recorded every 1-km, and electromyography and oxygen uptake were continually recorded and averaged each 1-km. Plasma lactate concentration was measured before and immediately after the trial. The time and mean power during the 4-km cycling time-trial was significantly improved (P< 0.05) in CAF (407.9 ± 24.5 s, 241.4 ± 16.1 W) compared to PLA (416.1 ± 34.1 s, 234.1 ± 19.2 W) and ACT (416.2 ± 26.6 s, 235.8 ± 19.7 W). However, there was no difference between ACTCAF (411.6 ± 27.7 s, 238.7 ± 18.7 W) and the other conditions (P> 0.05). The perception of pain, rating of perceived exertion, electromyography, oxygen uptake, and plasma lactate were similar across the conditions (P> 0.05). In conclusion, caffeine but not acetaminophen increases power output ultimately increasing performance during a 4-km cycling time-trial.

No Improvement in Endurance Performance after a Single Dose of Beetroot Juice

2012 ◽  
Vol 22 (6) ◽  
pp. 470-478 ◽  
Author(s):  
Naomi M. Cermak ◽  
Peter Res ◽  
Rudi Stinkens ◽  
Jon O. Lundberg ◽  
Martin J. Gibala ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Time Trial ◽  
Endurance Performance ◽  
Beetroot Juice ◽  
Double Blind ◽  
Single Bolus ◽  
Time Trial Performance ◽  
Subsequent Time ◽  
The Impact ◽  
Trial Performance

Introduction:Dietary nitrate supplementation has received much attention in the literature due to its proposed ergogenic properties. Recently, the ingestion of a single bolus of nitrate-rich beetroot juice (500 ml, ~6.2 mmol NO3−) was reported to improve subsequent time-trial performance. However, this large volume of ingested beetroot juice does not represent a realistic dietary strategy for athletes to follow in a practical, performancebased setting. Therefore, we investigated the impact of ingesting a single bolus of concentrated nitrate-rich beetroot juice (140 ml, ~8.7 mmol NO3−) on subsequent 1-hr time-trial performance in well-trained cyclists.Methods:Using a double-blind, repeated-measures crossover design (1-wk washout period), 20 trained male cyclists (26 ± 1 yr, VO2peak 60 ± 1 ml · kg−1 · min−1, Wmax 398 ± 7.7 W) ingested 140 ml of concentrated beetroot juice (8.7 mmol NO3−; BEET) or a placebo (nitrate-depleted beetroot juice; PLAC) with breakfast 2.5 hr before an ~1-hr cycling time trial (1,073 ± 21 kJ). Resting blood samples were collected every 30 min after BEET or PLAC ingestion and immediately after the time trial.Results:Plasma nitrite concentration was higher in BEET than PLAC before the onset of the time trial (532 ± 32 vs. 271 ± 13 nM, respectively; p < .001), but subsequent time-trial performance (65.5 ± 1.1 vs. 65 ± 1.1 s), power output (275 ± 7 vs. 278 ± 7 W), and heart rate (170 ± 2 vs. 170 ± 2 beats/min) did not differ between BEET and PLAC treatments (all p > .05).Conclusion:Ingestion of a single bolus of concentrated (140 ml) beetroot juice (8.7 mmol NO3−) does not improve subsequent 1-hr time-trial performance in well-trained cyclists.

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