scholarly journals The Ingestion of 39 or 64 g·hr−1 of Carbohydrate is Equally Effective at Improving Endurance Exercise Performance in Cyclists

2015 ◽  
Vol 25 (3) ◽  
pp. 285-292 ◽  
Author(s):  
Michael L. Newell ◽  
Angus M. Hunter ◽  
Claire Lawrence ◽  
Kevin D. Tipton ◽  
Stuart D. R. Galloway
Keyword(s):  
Power Output ◽  
Statistical Significance ◽  
Time Trial ◽  
Cycling Performance ◽  
Constant Load ◽  
Peak Power Output ◽  
Task Completion ◽  
Intake Rate ◽  
Mean Power ◽  
Pacing Strategy

In an investigator-blind, randomized cross-over design, male cyclists (mean± SD) age 34.0 (± 10.2) years, body mass 74.6 (±7.9) kg, stature 178.3 (±8.0) cm, peak power output (PPO) 393 (±36) W, and VO2max 62 (±9) ml·kg−1min−1 training for more than 6 hr/wk for more than 3y (n = 20) completed four experimental trials. Each trial consisted of a 2-hr constant load ride at 95% of lactate threshold (185 ± 25W) then a work-matched time trial task (~30min at 70% of PPO). Three commercially available carbohydrate (CHO) beverages, plus a control (water), were administered during the 2-hr ride providing 0, 20, 39, or 64g·hr−1 of CHO at a fluid intake rate of 1L·hr−1. Performance was assessed by time to complete the time trial task, mean power output sustained, and pacing strategy used. Mean task completion time (min:sec ± SD) for 39g·hr−1 (34:19.5 ± 03:07.1, p = .006) and 64g·hr−1 (34:11.3 ± 03:08.5 p = .004) of CHO were significantly faster than control (37:01.9 ± 05:35.0). The mean percentage improvement from control was −6.1% (95% CI: −11.3 to −1.0) and −6.5% (95% CI: −11.7 to −1.4) in the 39 and 64g·hr−1 trials respectively. The 20g·hr−1 (35:17.6 ± 04:16.3) treatment did not reach statistical significance compared with control (p = .126) despite a mean improvement of −3.7% (95% CI −8.8−1.5%). No further differences between CHO trials were reported. No interaction between CHO dose and pacing strategy occurred. 39 and 64g·hr−1 of CHO were similarly effective at improving endurance cycling performance compared with a 0g·hr−1 control in our trained cyclists.

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.

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.

Combined Glucose Ingestion and Mouth Rinsing Improves Sprint Cycling Performance

2014 ◽  
Vol 24 (6) ◽  
pp. 605-612 ◽  
Author(s):  
Edwin Chong ◽  
Kym J. Guelfi ◽  
Paul A. Fournier
Keyword(s):  
Blood Glucose ◽  
Power Output ◽  
Cycling Performance ◽  
Cycle Ergometer ◽  
Peak Power Output ◽  
Mean Power ◽  
Glucose Ingestion ◽  
Sprint Cycling ◽  
Double Blinded ◽  
Mouth Rinsing

This study investigated whether combined ingestion and mouth rinsing with a carbohydrate solution could improve maximal sprint cycling performance. Twelve competitive male cyclists ingested 100 ml of one of the following solutions 20 min before exercise in a randomized double-blinded counterbalanced order (a) 10% glucose solution, (b) 0.05% aspartame solution, (c) 9.0% maltodextrin solution, or (d) water as a control. Fifteen min after ingestion, repeated mouth rinsing was carried out with 11 × 15 ml bolus doses of the same solution at 30-s intervals. Each participant then performed a 45-s maximal sprint effort on a cycle ergometer. Peak power output was significantly higher in response to the glucose trial (1188 ± 166 W) compared with the water (1036 ± 177 W), aspartame (1088 ± 128 W) and maltodextrin (1024 ± 202W) trials by 14.7 ± 10.6, 9.2 ± 4.6 and 16.0 ± 6.0% respectively (p < .05). Mean power output during the sprint was significantly higher in the glucose trial compared with maltodextrin (p < .05) and also tended to be higher than the water trial (p = .075). Glucose and maltodextrin resulted in a similar increase in blood glucose, and the responses of blood lactate and pH to sprinting did not differ significantly between treatments (p > .05). These findings suggest that combining the ingestion of glucose with glucose mouth rinsing improves maximal sprint performance. This ergogenic effect is unlikely to be related to changes in blood glucose, sweetness, or energy sensing mechanisms in the gastrointestinal tract.

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.

The Effects of Medium-Chain Triacylglycerol and Carbohydrate Ingestion on Ultra-Endurance Exercise Performance

2005 ◽  
Vol 15 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Julia H. Goedecke ◽  
Virginia R. Clark ◽  
Timothy D. Noakes ◽  
Estelle V. Lambert
Keyword(s):  
Time Trial ◽  
Cycling Performance ◽  
Constant Load ◽  
Peak Power Output ◽  
Carbohydrate Ingestion ◽  
Medium Chain ◽  
Substrate Metabolism ◽  
Endurance Cycling ◽  
Gi Symptoms ◽  
Ultra Endurance

The aims of the study were to determine if medium-chain triacylglycerol (MCT), ingested in combination with carbohydrate (CHO), would alter substrate metabolism and improve simulated competitive ultra-endurance cycling performance. Eight endurance-trained cyclists took part in this randomized, single-blind crossover study. On two separate occasions, subjects cycled for 270 min at 50% of peak power output, interspersed with four 75 kJ sprints at 60 min intervals, followed immediately by a 200 kJ time-trial. One hour prior to the exercise trials, subjects ingested either 75 g of CHO or 32 g of MCT, and then ingested 200 mL of a 10% CHO (wt/vol) solution or a 4.3% MCT + 10% CHO (wt/vol) solution every 20 min during the CHO and MCT trials, respectively. During the constant-load phases of the 270 min exercise trial, VO2, RER, and heart rate were measured at 30 min intervals and gastrointestinal (GI) symptoms were recorded. There was no difference in VO2 or RER between the MCT and CHO trials (P = 0.40). Hourly sprint (P = 0.03 for trial x time interaction) and time-trial times (14:30 ± 0.58 vs. 12:36 ± 1:6, respectively, P < 0.001) were slower in the MCT than the CHO trial. Half the subjects experienced GI symptoms with MCT ingestion. In conclusion, MCTs ingested prior to exercise and co-ingested with CHO during exercise did not alter substrate metabolism and significantly compromised sprint performance during prolonged ultra-endurance cycling exercise.

Predicting Cycling Performance in Trained to Elite Male and Female Cyclists

2014 ◽  
Vol 9 (4) ◽  
pp. 610-614 ◽  
Author(s):  
Robert P. Lamberts
Keyword(s):  
Power Output ◽  
High Performance ◽  
Perceived Exertion ◽  
Maximal Oxygen Consumption ◽  
Average Power ◽  
Time Trial ◽  
Cycling Performance ◽  
Gas Analysis ◽  
Peak Power Output ◽  
Male And Female

In high-performance cycling, it is important to maintain a healthy balance between training load and recovery. Recently a new submaximal cycle test, known as the Lamberts and Lambert Submaximal Cycle Test (LSCT), has been shown to be able to accurately predict cycling performance in 15 well-trained cyclists. The aim of this study was to determine the predictive value of the LSCT in 102 trained to elite cyclists (82 men and 20 women). All cyclists performed an LSCT test followed by a peak-power-output (PPO) test, which included respiratory-gas analysis for the determination of maximal oxygen consumption (VO2max). They then performed the LSCT test followed by a 40-km time trial (TT) 72 h later. Average power output during the 3 stages of the LSCT increased from 31%, 60%, and 79% of PPO, while the ratings of perceived exertion increased from 8 to 13 to 16. Very good relationships were found between actual and LSCT-predicted PPO (r = .98, 95%CI: .97–.98, P < .0001), VO2max (r = .96, 95%CI: .97–.99, P < .0001) and 40-km-TT time (r = .98, 95%CI: .94–.97, P < .0001). No gender differences were found when predicting cycling performance from the LSCT (P = .95). The findings of this study show that the LSCT is able to accurately predict cycling performance in trained to elite male and female cyclists and potentially can be used to prescribe and fine-tune training prescription in cycling.

scholarly journals Ingesting a Bitter Solution: The Sweet Touch to Increasing Short-Term Cycling Performance

2019 ◽  
Vol 14 (6) ◽  
pp. 727-732
Author(s):  
Naroa Etxebarria ◽  
Megan L. Ross ◽  
Brad Clark ◽  
Louise M. Burke
Keyword(s):  
Power Output ◽  
Time Trial ◽  
Cycling Performance ◽  
Sporting Events ◽  
Mean Power ◽  
Cycling Time Trial ◽  
Sweet Solution ◽  
Overall Performance ◽  
Mean Power Output ◽  
Ergometer Test

Purpose: The authors investigated the potential benefit of ingesting 2 mM of quinine (bitter tastant) on a 3000-m cycling time-trial (TT) performance. Methods: Nine well-trained male cyclists (maximal aerobic power: 386 [38] W) performed a maximal incremental cycling ergometer test, three 3000-m familiarization TTs, and four 3000-m intervention TTs (∼4 min) on consecutive days. The 4 interventions were (1) 25 mL of placebo, (2) a 25-mL sweet solution, and (3) and (4) repeat 25 mL of 2-mM quinine solutions (Bitter1 and Bitter2), 30 s before each trial. Participants self-selected their gears and were only aware of distance covered. Results: Overall mean power output for the full 3000 m was similar for all 4 conditions: placebo, 348 (45) W; sweet, 355 (47) W; Bitter1, 354 (47) W; and Bitter2, 355 (48) W. However, quinine administration in Bitter1 and Bitter2 increased power output during the first kilometer by 15 ± 11 W and 21 ± 10 W (mean ± 90% confidence limits), respectively, over placebo, followed by a decay of 34 ± 32 W during Bitter1 and Bitter2 during the second kilometer. Bitter2 also induced a 11 ± 13-W increase during the first kilometer compared with the sweet condition. Conclusions: Ingesting 2 mM of quinine can improve cycling performance during the first one-third of a 3000-m TT and could be used for sporting events lasting ∼80 s to potentially improve overall performance.

scholarly journals Transcranial direct current stimulation does not enhance cycling time-trial performance

2019 ◽  
Author(s):  
Justin Andre ◽  
Ann-Maree Vallence ◽  
Hakuei Fujiyama ◽  
Jeremiah Peiffer
Keyword(s):  
Direct Current ◽  
Power Output ◽  
Transcranial Direct Current Stimulation ◽  
Primary Motor Cortex ◽  
Time Trial ◽  
Cycling Performance ◽  
Time To Exhaustion ◽  
Mean Power ◽  
Mean Values ◽  
Direct Current Stimulation

Transcranial direct current stimulation (tDCS) to the primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) have separately been shown to increase performance during fixed-work time-to-exhaustion tasks. No studies have examined application of tDCS to these cortical sites in a single study or during self-paced tasks. Objectives: This study examined the influence of anodal-tDCS (A-tDCS) applied to M1 and DLPFC on cycling performance during a self-paced 16.1-km time trial (TT). Design: randomised cross-over design. Methods: Ten cyclists received 20 min of A-tDCS (1.5 mA) applied to M1, DLPFC or the visual cortex (V1; control), followed by a standardised 10-min warmup and a 16.1-km cycling TT. During the TT, heart rate and power output were continuously recorded and mean values for each quartile of the total TT duration were calculated. Ratings of perceive exertion (RPE) were collected at four, eight, 12 and 16.1 km. RESULTS: No differences were observed for the time-to-complete (p=0.07; BF10=1.24) or mean power output (p=0.09; BF10=1.11) during the 16.1-km TT between the M1 (1443.7±81.0 s and 274±44 W), DLPFC (1428.4±80.0 s and 280±39 W) and V1 (1434.8±9.6 s and 279±44 W) conditions. Both HR and RPE progressively increased from the first quartile of the TT with no differences observed between A-tDCS conditions. CONCLUSION: A-tDCS does not represents a viable method to decrease the physiological and perceptual stress during or enhance the performance of a self-paced cycling TT. Nevertheless, these findings should be viewed with respect to the inherent complexities between performance, fatigue and the brain.

Oral Presence of Carbohydrate and Caffeine in Chewing Gum: Independent and Combined Effects on Endurance Cycling Performance

2016 ◽  
Vol 11 (2) ◽  
pp. 164-171 ◽  
Author(s):  
Katherine T. Oberlin-Brown ◽  
Rodney Siegel ◽  
Andrew E. Kilding ◽  
Paul B. Laursen
Keyword(s):  
Prolonged Exercise ◽  
Ventilatory Threshold ◽  
Time Trial ◽  
Cycling Performance ◽  
Constant Load ◽  
Chewing Gum ◽  
Combined Effects ◽  
Mean Power ◽  
Cycling Time Trial ◽  
Load Cycling

The oral presence of carbohydrate (CHO) and caffeine (CAF) may independently enhance exercise performance, but their influence on performance during prolonged exercise is less known.Aim:To determine the independent and combined effects of CHO and CAF administered in chewing gum during a cycling time trial (TT) after prolonged exercise.Method:Eleven male cyclists (32.2 ± 7.5 y, 74.3 ± 6.8 kg, 60.2 ± 4.0 mL · kg–1 · min–1 V˙O2peak) performed 4 experimental trials consisting of 90-min constant-load cycling at 80% of their second ventilatory threshold (207 ± 30 W), followed immediately by a 20-km TT. Under double-blinded conditions, cyclists received placebo (PLA), CHO, CAF, or a combined CHO+CAF chewing gum at 0-, 5-, 10-, and 15-km points of the TT.Results:Overall TT performance was similar across experimental and PLA trials (%mean difference ± 90%CL 0.2% ± 2.0%, 0.4% ± 2.2%, 0.1% ± 1.8% for CHO, CAF, and CHO+CAF). Compared with PLA, mean power output tended to be higher in the first 2 quarters of the TT with CHO (1.6% ± 3.1% and 0.8% ± 2.0%) and was substantially improved in the last 2 quarters during CAF and CHO+CAF trials (4.2% ± 3.0% and 2.0% ± 1.8%). There were no differences in average heart rate (ES <0.2) and only small changes in blood glucose (ES 0.2), which were unrelated to performance. Blood lactate was substantially higher post-TT for CAF and CHO+CAF (ES >0.6).Conclusion:After prolonged constant-load cycling, the oral presence of CHO and CAF in chewing gum, independently or in combination, did not improve overall performance but did influence pacing.

Effect of Recovery Interventions on Cycling Performance and Pacing Strategy in the Heat

2014 ◽  
Vol 9 (2) ◽  
pp. 240-248 ◽  
Author(s):  
Kevin De Pauw ◽  
Bart Roelands ◽  
Jef Vanparijs ◽  
Romain Meeusen
Keyword(s):  
Power Output ◽  
Cold Water ◽  
Water Immersion ◽  
Thermal Strain ◽  
Time Trial ◽  
Cycling Performance ◽  
Cold Water Immersion ◽  
Active Recovery ◽  
Maximal Power Output ◽  
Pacing Strategy

Purpose:To determine the effect of active recovery (AR), passive rest (PR), and cold-water immersion (CWI) after 90 min of intensive cycling on a subsequent 12-min time trial (TT2) and the applied pacing strategy in TT2.Methods:After a maximal test and familiarization trial, 9 trained male subjects (age 22 ± 3 y, VO2max 62.1 ± 5.3 mL · min−1 · kg−1) performed 3 experimental trials in the heat (30°C). Each trial consisted of 2 exercise tasks separated by 1 h. The first was a 60-min constant-load trial at 55% of the maximal power output followed by a 30-min time trial (TT1). The second comprised a 12-min simulated time trial (TT2). After TT1, AR, PR, or CWI was applied for 15 min.Results:No significant TT2 performance differences were observed, but a 1-sample t test (within each condition) revealed different pacing strategies during TT2. CWI resulted in an even pacing strategy, while AR and PR resulted in a gradual decline of power output after the onset of TT2 (P ≤ .046). During recovery, AR and CWI showed a trend toward faster blood lactate ([BLa]) removal, but during TT2 significantly higher [BLa] was only observed after CWI compared with PR (P = .011).Conclusion:The pacing strategy during subsequent cycling performance in the heat is influenced by the application of different postexercise recovery interventions. Although power was not significantly altered between groups, CWI enabled a differently shaped power profile, likely due to decreased thermal strain.

Sign in / Sign up

Export Citation Format

Share Document