High-Fat Diet versus Habitual Diet Prior to Carbohydrate Loading: Effects on Exercise Metabolism and Cycling Performance

2001 ◽  
Vol 11 (2) ◽  
pp. 209-225 ◽  
Author(s):  
Estelle V. Lambert ◽  
Julia H. Goedecke ◽  
Charl van Zyl ◽  
Kim Murphy ◽  
John A. Hawley ◽  
...  
Keyword(s):  
Muscle Glycogen ◽  
High Fat Diet ◽  
Time Trial ◽  
Cycling Performance ◽  
Peak Oxygen Uptake ◽  
High Fat ◽  
Lactate Oxidation ◽  
Cycling Time Trial ◽  
Habitual Diet ◽  
Loading Effects

We examined the effects of a high-fat diet (HFD-CHO) versus a habitual diet, prior to carbohydrate (CHO)-loading on fuel metabolism and cycling time-trial (TT) performance. Five endurance-trained cyclists participated in two 14-day randomized cross-over trials during which subjects consumed either a HFD (>65% MJ from fat) or their habitual diet (CTL) (30 ± 5% MJ from fat) for 10 day, before ingesting a high-CHO diet (CHO-loading, CHO > 70% MJ) for 3 days. Trials consisted of a 150-min cycle at 70% of peak oxygen uptake (V̇O2peak), followed immediately by a 20-km TT. One hour before each trial, cyclists ingested 400 ml of a 3.44% medium-chain triacylglycerol (MCT) solution, and during the trial, ingested 600 ml/hour of a 10% 14C-glucose + 3.44% MCT solution. The dietary treatments did not alter the subjects’ weight, body fat, or lipid profile. There were also no changes in circulating glucose, lactate, free fatty acid (FFA), and β-hydroxybutyrate concentrations during exercise. However, mean serum glycerol concentrations were significantly higher (p < .01) in the HFD-CHO trial. The HFD-CHO diet increased total fat oxidation and reduced total CHO oxidation but did not alter plasma glucose oxidation during exercise. By contrast, the estimated rates of muscle glycogen and lactate oxidation were lower after the HFD-CHO diet. The HFD-CHO treatment was also associated with improved TT times (29.5 ± 2.9 min vs. 30.9 ± 3.4 min for HFD-CHO and CTL-CHO, p < .05). High-fat feeding for 10 days prior to CHO-loading was associated with an increased reliance on fat, a decreased reliance on muscle glycogen, and improved time trial performance after prolonged exercise.

Effect of fat adaptation and carbohydrate restoration on metabolism and performance during prolonged cycling

2000 ◽  
Vol 89 (6) ◽  
pp. 2413-2421 ◽  
Author(s):  
Louise M. Burke ◽  
Damien J. Angus ◽  
Gregory R. Cox ◽  
Nicola K. Cummings ◽  
Mark A. Febbraio ◽  
...  
Keyword(s):  
Muscle Glycogen ◽  
High Fat Diet ◽  
Performance Testing ◽  
Time Trial ◽  
Random Order ◽  
Cycling Performance ◽  
High Fat ◽  
Glycogen Utilization ◽  
And Performance ◽  
Glycogen Sparing

For 5 days, eight well-trained cyclists consumed a random order of a high-carbohydrate (CHO) diet (9.6 g · kg−1 · day−1 CHO, 0.7 g · kg−1 · day−1 fat; HCHO) or an isoenergetic high-fat diet (2.4 g · kg−1 · day−1 CHO, 4 g · kg−1 · day−1 fat; Fat-adapt) while undertaking supervised training. On day 6,subjects ingested high CHO and rested before performance testing on day 7 [2 h cycling at 70% maximal O2consumption (SS) + 7 kJ/kg time trial (TT)]. With Fat-adapt, 5 days of high-fat diet reduced respiratory exchange ratio (RER) during cycling at 70% maximal O2 consumption; this was partially restored by 1 day of high CHO [0.90 ± 0.01 vs. 0.82 ± 0.01 ( P < 0.05) vs. 0.87 ± 0.01 ( P < 0.05), for day 1, day 6, and day 7, respectively]. Corresponding RER values on HCHO trial were [0.91 ± 0.01 vs. 0.88 ± 0.01 ( P < 0.05) vs. 0.93 ± 0.01 ( P < 0.05)]. During SS, estimated fat oxidation increased [94 ± 6 vs. 61 ± 5 g ( P < 0.05)], whereas CHO oxidation decreased [271 ± 16 vs. 342 ± 14 g ( P < 0.05)] for Fat-adapt compared with HCHO. Tracer-derived estimates of plasma glucose uptake revealed no differences between treatments, suggesting muscle glycogen sparing accounted for reduced CHO oxidation. Direct assessment of muscle glycogen utilization showed a similar order of sparing (260 ± 26 vs. 360 ± 43 mmol/kg dry wt; P = 0.06). TT performance was 30.73 ± 1.12 vs. 34.17 ± 2.48 min for Fat-adapt and HCHO ( P = 0.21). These data show significant metabolic adaptations with a brief period of high-fat intake, which persist even after restoration of CHO availability. However, there was no evidence of a clear benefit of fat adaptation to cycling performance.

scholarly journals The Potential to Change Pacing and Performance During 4000-m Cycling Time Trials Using Hyperoxia and Inspired Gas-Content Deception

2019 ◽  
Vol 14 (7) ◽  
pp. 949-957
Author(s):  
Michael J. Davies ◽  
Bradley Clark ◽  
Laura A. Garvican-Lewis ◽  
Marijke Welvaert ◽  
Christopher J. Gore ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Time Trial ◽  
Cycling Performance ◽  
Peak Oxygen Uptake ◽  
Gas Content ◽  
Cycling Time Trial ◽  
Fraction Of Inspired Oxygen ◽  
And Performance ◽  
Inspired Oxygen ◽  
Cycling Time

Purpose: To determine if a series of trials with fraction of inspired oxygen (FiO2) content deception could improve 4000-m cycling time-trial (TT) performance. Methods: A total of 15 trained male cyclists (mean [SD] body mass 74.2 [8.0] kg, peak oxygen uptake 62 [6] mL·kg−1·min−1) completed six 4000-m cycling TTs in a semirandomized order. After a familiarization TT, cyclists were informed in 2 initial trials they were inspiring normoxic air (NORM, FiO2 0.21); however, in 1 trial (deception condition), they inspired hyperoxic air (NORM-DEC, FiO2 0.36). During 2 subsequent TTs, cyclists were informed they were inspiring hyperoxic air (HYPER, FiO2 0.36), but in 1 trial, normoxic air was inspired (HYPER-DEC). In the final TT (NORM-INFORM), the deception was revealed and cyclists were asked to reproduce their best TT performance while inspiring normoxic air. Results: Greater power output and faster performances occurred when cyclists inspired hyperoxic air in both truthful (HYPER) and deceptive (NORM-DEC) trials than NORM (P < .001). However, performance only improved in NORM-INFORM (377 W; 95% confidence interval [CI] 325–429) vs NORM (352 W; 95% CI 299–404; P < .001) when participants (n = 4) completed the trials in the following order: NORM-DEC, NORM, HYPER-DEC, HYPER. Conclusions: Cycling performance improved with acute exposure to hyperoxia. Mechanisms for the improvement were likely physiological; however, improvement in a deception trial suggests an additional placebo effect. Finally, a particular sequence of oxygen deception trials may have built psychophysiological belief in cyclists such that performance improved in a subsequent normoxic trial.

Dietary Antioxidant Supplementation Combined with Quercetin Improves Cycling Time Trial Performance

2006 ◽  
Vol 16 (4) ◽  
pp. 405-419 ◽  
Author(s):  
Holden S-H. MacRae ◽  
Kari M. Mefferd
Keyword(s):  
Peak Power ◽  
Time Trial ◽  
Cycling Performance ◽  
Antioxidant Supplementation ◽  
Double Blind ◽  
Cycling Time Trial ◽  
Dietary Antioxidant ◽  
Power Peak ◽  
Manova Analysis ◽  
Trial Performance

We investigated whether 6 wk of antioxidant supplementation (AS) would enhance 30 km time trial (TT) cycling performance. Eleven elite male cyclists completed a randomized, double-blind, cross-over study to test the effects of twice daily AS containing essential vitamins plus quercetin (FRS), and AS minus quercetin (FRS-Q) versus a baseline TT (B). MANOVA analysis showed that time to complete the 30 km TT was improved by 3.1% on FRS compared to B (P ≤ 0.01), and by 2% over the last 5 km (P ≤ 0.05). Absolute and relative (%HRmax) heart rates and percent VO2max were not different between trials, but average and relative power (% peak power) was higher on FRS (P ≤ 0.01). Rates of carbohydrate and fat oxidation were not different between trials. Thus, FRS supplementation significantly improved high-intensity cycling TT performance through enhancement of power output. Further study is needed to determine the potential mechanism(s) of the antioxidant efficacy.

scholarly journals Effects of fat adaptation and carbohydrate restoration on prolonged endurance exercise

2001 ◽  
Vol 91 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Andrew L. Carey ◽  
Heidi M. Staudacher ◽  
Nicola K. Cummings ◽  
Nigel K. Stepto ◽  
Vasilis Nikolopoulos ◽  
...  
Keyword(s):  
Endurance Exercise ◽  
Power Output ◽  
High Fat Diet ◽  
Respiratory Exchange Ratio ◽  
Time Trial ◽  
Fat Oxidation ◽  
Significant Benefit ◽  
High Fat ◽  
Competitive Athletes ◽  
And Performance

We determined the effect of fat adaptation on metabolism and performance during 5 h of cycling in seven competitive athletes who consumed a standard carbohydrate (CHO) diet for 1 day and then either a high-CHO diet (11 g · kg−1 · day−1 CHO, 1 g · kg−1 · day−1 fat; HCHO) or an isoenergetic high-fat diet (2.6 g · kg−1 · day−1 CHO, 4.6 g · kg−1 · day−1 fat; fat-adapt) for 6 days. On day 8, subjects consumed a high-CHO diet and rested. On day 9, subjects consumed a preexercise meal and then cycled for 4 h at 65% peak O2 uptake, followed by a 1-h time trial (TT). Compared with baseline, 6 days of fat-adapt reduced respiratory exchange ratio (RER) with cycling at 65% peak O2 uptake [0.78 ± 0.01 (SE) vs. 0.85 ± 0.02; P < 0.05]. However, RER was restored by 1 day of high-CHO diet, preexercise meal, and CHO ingestion (0.88 ± 0.01; P < 0.05). RER was higher after HCHO than fat-adapt (0.85 ± 0.01, 0.89 ± 0.01, and 0.93 ± 0.01 for days 2, 8, and 9, respectively; P < 0.05). Fat oxidation during the 4-h ride was greater (171 ± 32 vs. 119 ± 38 g; P < 0.05) and CHO oxidation lower (597 ± 41 vs. 719 ± 46 g; P < 0.05) after fat-adapt. Power output was 11% higher during the TT after fat-adapt than after HCHO (312 ± 15 vs. 279 ± 20 W; P = 0.11). In conclusion, compared with a high-CHO diet, fat oxidation during exercise increased after fat-adapt and remained elevated above baseline even after 1 day of a high-CHO diet and increased CHO availability. However, this study failed to detect a significant benefit of fat adaptation to performance of a 1-h TT undertaken after 4 h of cycling.

The Effect of Higher Than Recommended Protein Feedings Post-Exercise on Recovery Following Downhill Running in Masters Triathletes

2017 ◽  
Vol 27 (1) ◽  
pp. 76-82 ◽  
Author(s):  
Thomas M. Doering ◽  
Peter R. Reaburn ◽  
Nattai R. Borges ◽  
Gregory R. Cox ◽  
David G. Jenkins
Keyword(s):  
Beneficial Effect ◽  
Protein Intake ◽  
Knee Extensor ◽  
Time Trial ◽  
Cycling Performance ◽  
Treatment Change ◽  
Cycling Time Trial ◽  
Beneficial Effects ◽  
Masters Athletes ◽  
Exercise Induced

Following exercise-induced muscle damage (EIMD), masters athletes take longer to recover than younger athletes. The purpose of this study was to determine the effect of higher than recommended postexercise protein feedings on the recovery of knee extensor peak isometric torque (PIT), perceptions of recovery, and cycling time trial (TT) performance following EIMD in masters triathletes. Eight masters triathletes (52 ± 2 y, V̇O2max, 51.8 ± 4.2 ml•kg-1•min-1) completed two trials separated by seven days in a randomized, doubleblind, crossover study. Trials consisted of morning PIT testing and a 30-min downhill run followed by an eight-hour recovery. During recovery, a moderate (MPI; 0.3 g•kg-1•bolus-1) or high (0.6 g•kg-1•bolus-1) protein intake (HPI) was consumed in three bolus feedings at two hour intervals commencing immediately postexercise. PIT testing and a 7 kJ•kg-1 cycling TT were completed postintervention. Perceptions of recovery were assessed pre- and postexercise. The HPI did not significantly improve recovery compared with MPI (p > .05). However, comparison of within-treatment change shows the HPI provided a moderate beneficial effect (d = 0.66), attenuating the loss of afternoon PIT (-3.6%, d = 0.09) compared with the MPI (-8.6%, d = 0.24). The HPI provided a large beneficial effect (d = 0.83), reducing perceived fatigue over the eight-hour recovery (d = 1.25) compared with the MPI (d = 0.22). Despite these effects, cycling performance was unchanged (HPI = 2395 ± 297 s vs. MPI = 2369 ± 278 s; d = 0.09). In conclusion, doubling the recommended postexercise protein intake did not significantly improve recovery in masters athletes; however, HPI provided moderate to large beneficial effects on recovery that may be meaningful following EIMD.

Influence of 2-Weeks Ingestion of High Chlorogenic Acid Coffee on Mood State, Performance, and Postexercise Inflammation and Oxidative Stress: A Randomized, Placebo-Controlled Trial

2018 ◽  
Vol 28 (1) ◽  
pp. 55-65 ◽  
Author(s):  
David C. Nieman ◽  
Courtney L. Goodman ◽  
Christopher R. Capps ◽  
Zack L. Shue ◽  
Robert Arnot
Keyword(s):  
Oxidative Stress ◽  
Chlorogenic Acid ◽  
Mood State ◽  
Controlled Trial ◽  
Time Trial ◽  
Cycling Performance ◽  
Cycling Time Trial ◽  
Reducing Ability ◽  
And Oxidative Stress ◽  
Cycling Time

This study measured the influence of 2-weeks ingestion of high chlorogenic acid (CQA) coffee on postexercise inflammation and oxidative stress, with secondary outcomes including performance and mood state. Cyclists (N = 15) were randomized to CQA coffee or placebo (300 ml/day) for 2 weeks, participated in a 50-km cycling time trial, and then crossed over to the opposite condition with a 2-week washout period. Blood samples were collected pre- and postsupplementation, and immediately postexercise. CQA coffee was prepared using the Turkish method with 30 g lightly roasted, highly ground Hambela coffee beans in 300 ml boiling water, and provided 1,066 mg CQA and 474 mg caffeine versus 187 mg CQA and 33 mg caffeine for placebo. Plasma caffeine was higher with CQA coffee versus placebo after 2-weeks (3.3-fold) and postexercise (21.0-fold) (interaction effect, p < .001). Higher ferric reducing ability of plasma (FRAP) levels were measured after exercise with CQA coffee versus placebo (p = .01). No differences between CQA coffee and placebo were found for postexercise increases in plasma IL-6 (p = .74) and hydroxyoctadecadienoic acids (9 + 13 HODEs) (p = .99). Total mood disturbance (TMD) scores were lower with CQA coffee versus placebo (p = .04). 50-km cycling time performance and power did not differ between trials, with heart rate and ventilation higher with CQA coffee, especially after 30 min. In summary, despite more favorable TMD scores with CQA coffee, these data do not support the chronic use of coffee highly concentrated with chlorogenic acids and caffeine in mitigating postexercise inflammation or oxidative stress or improving 50-km cycling performance.

An Isocaloric Glucose-Fructose Beverage’s Effect on Simulated 100-km Cycling Performance Compared With a Glucose-Only Beverage

2010 ◽  
Vol 20 (2) ◽  
pp. 122-131 ◽  
Author(s):  
Darren Triplett ◽  
J. Andrew Doyle ◽  
Jeffrey C. Rupp ◽  
Dan Benardot
Keyword(s):  
Time Trial ◽  
Endurance Performance ◽  
Cycling Performance ◽  
Peak Oxygen Uptake ◽  
Cycle Ergometer ◽  
Oxidation Rates ◽  
Familiarization Trial ◽  
Competitive Cyclists ◽  
Experimental Trials ◽  
Time Point

A number of recent research studies have demonstrated that providing glucose and fructose together in a beverage consumed during exercise results in significantly higher oxidation rates of exogenous carbohydrate (CHO) than consuming glucose alone. However, there is insufficient evidence to determine whether the increased exogenous CHO oxidation improves endurance performance. The purpose of this study was to determine whether consuming a beverage containing glucose and fructose (GF) would result in improved cycling performance compared with an isocaloric glucose-only beverage (G). Nine male competitive cyclists (32.6 ± 5.8 years, peak oxygen uptake 61.5 ± 7.9 ml · kg-1 · min-1) completed a familiarization trial and then 2 simulated 100-km cycling time trials on an electronically braked Lode cycle ergometer separated by 5–7 d. During the randomly ordered experimental trials, participants received 36 g of CHO of either G or GF in 250 ml of water every 15 min. All 9 participants completed the 100-km time trial significantly faster when they received the GF beverage than with G (204.0 ± 23.7 vs. 220.6 ± 36.6 min; p = .023). There was no difference at any time point between trials for blood glucose or for blood lactate. Total CHO oxidation increased significantly from rest during exercise but was not statistically significant between the GF and G trials, although there was a trend for CHO oxidation to be higher with GF in the latter stages of the time trial. Consumption of a CHO beverage containing glucose and fructose results in improved 100-km cycling performance compared with an isocaloric glucose-only beverage.

Effect of Repeated Sodium Phosphate Loading on Cycling Time-Trial Performance and VO2peak

2013 ◽  
Vol 23 (2) ◽  
pp. 187-194 ◽  
Author(s):  
Cameron P. Brewer ◽  
Brian Dawson ◽  
Karen E. Wallman ◽  
Kym J. Guelfi
Keyword(s):  
Sodium Phosphate ◽  
Time Trial ◽  
Peak Oxygen Uptake ◽  
Fat Free Mass ◽  
Mean Power ◽  
Time Trial Performance ◽  
Cycling Time Trial ◽  
Placebo Phase ◽  
Cycling Time ◽  
Trial Performance

Research into supplementation with sodium phosphate has not investigated the effects of a repeated supplementation phase. Therefore, this study examined the potential additive effects of repeated sodium phosphate (SP) supplementation on cycling time-trial performance and peak oxygen uptake (VO2peak). Trained male cyclists (N = 9, M ± SD VO2peak = 65.2 ± 4.8 ml · kg−1 · min−1) completed baseline 1,000-kJ time-trial and VO2peak tests separated by 48 hr, then ingested either 50 mg · kg fat-free mass−1 · d−1 of tribasic SP or a combined glucose and NaCl placebo for 6 d before performing these tests again. A 14-d washout period separated the end of one loading phase and the start of the next, with 2 SP and 1 placebo phase completed in a counterbalanced order. Although time-trial performance (55.3–56.5 min) was shorter in SP1 and SP2 (~60–70 s), effect sizes and smallest-worthwhile-change values did not differ in comparison with baseline and placebo. However, mean power output was greater than placebo during time-trial performance at the 250-kJ and 500-kJ time points (p < .05) after the second SP phase. Furthermore, mean VO2peak values (p < .01) were greater after the SP1 (3.5–4.3%), with further improvements (p < .01) found in SP2 (7.1–7.7%), compared with baseline and placebo. In summary, repeated SP supplementation, ingested either 15 or 35 d after initial loading, can have an additive effect on VO2peak and possibly time-trial performance.

Reliability of Physiological Attributes and Their Association With Stochastic Cycling Performance

2014 ◽  
Vol 9 (2) ◽  
pp. 309-315 ◽  
Author(s):  
Gregory T. Levin ◽  
Paul B. Laursen ◽  
Chris R. Abbiss
Keyword(s):  
Power Output ◽  
Ventilatory Threshold ◽  
Intraclass Correlation ◽  
Time Trial ◽  
Cycling Performance ◽  
Peak Power Output ◽  
Cycling Time Trial ◽  
Physiological Variables ◽  
Physiological Attributes ◽  
And Performance

Purpose:To assess the reliability of a 5-min-stage graded exercise test (GXT) and determine the association between physiological attributes and performance over stochastic cycling trials of varying distance.Methods:Twenty-eight well-trained male cyclists performed 2 GXTs and either a 30-km (n = 17) or a 100-km stochastic cycling time trial (n = 9). Stochastic cycling trials included periods of high-intensity efforts for durations of 250 m, 1 km, or 4 km depending on the test being performing.Results:Maximal physiological attributes were found to be extremely reliable (maximal oxygen uptake [VO2max]: coefficient of variation [CV] 3.0%, intraclass correlation coefficient [ICC] .911; peak power output [PPO]: CV 3.0%, ICC .913), but a greater variability was found in ventilatory thresholds and economy. All physiological variables measured during the GXT, except economy at 200 W, were correlated with 30-km cycling performance. Power output during the 250-m and 1-km efforts of the 30-km trial were correlated with VO2max, PPO, and the power output at the second ventilatory threshold (r = .58–.82). PPO was the only physiological attributed measured during the GXT to be correlated with performance during the 100-km cycling trial (r = .64).Conclusions:Many physiological variables from a reliable GXT were associated with performance over shorter (30-km) but not longer (100-km) stochastic cycling trials.

scholarly journals Sex-Specific Effects of Respiratory Muscle Endurance Training on Cycling Time Trial Performance in Normoxia and Hypoxia

2021 ◽  
Vol 12 ◽  
Author(s):  
Julie Chambault ◽  
Grégorine Grand ◽  
Bengt Kayser
Keyword(s):  
Heart Rate ◽  
Endurance Training ◽  
Respiratory System ◽  
Respiratory Muscle ◽  
Time Trial ◽  
Cycling Performance ◽  
Muscle Endurance ◽  
Cycling Time Trial ◽  
Respiratory Muscle Endurance ◽  
Cycling Time

Objectives: We tested the hypotheses that respiratory muscle endurance training (RMET) improves endurance cycling performance differently in women and men and more so in hypoxia than in normoxia.Design: A prospective pre–post cross-over study with two testing conditions.Methods: Healthy and active women (seven, 24 ± 4 years, mean ± standard deviation [SD]) and men (seven, 27 ± 5 years) performed incremental cycling to determine maximum oxygen consumption (VO2peak) and power output (Wpeak) and on different days two 10-km cycling time trials (TTs) in normoxia and normobaric hypoxia (FiO2, 0.135, ~3,500 m equivalent), in a balanced randomized order. Next they performed supervised RMET in normoxia (4 weeks, 5 days/week, 30 min/day eucapnic hyperpnea at ~60% predicted maximum voluntary ventilation) followed by identical post-tests. During TTs, heart rate, ear oximetry reading, and Wpeak were recorded.Results: The VO2peak and Wpeak values were unchanged after RMET. The TT was improved by 7 ± 6% (p &lt; 0.001) in normoxia and 16 ± 6% (p &lt; 0.001) in hypoxia. The difference between normoxic and hypoxic TT was smaller after RMET as compared with that before RMET (14% vs. 21%, respectively, p &lt; 0.001). All effects were greater in women (p &lt; 0.001). The RMET did not change the heart rate or ear oximetry reading during TTs.Conclusion: We found a greater effect of RMET on cycling TT performance in women than in men, an effect more pronounced in hypoxia. These findings are congruent with the contention of a more pronounced performance-limiting role of the respiratory system during endurance exercise in hypoxia compared with normoxia and more so in women whose respiratory system is undersized compared with that of men.

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