The Isocapnic Buffering Phase and Mechanical Efficiency: Relationship to Cycle Time Trial Performance of Short and Long Duration

2005 ◽  
Vol 30 (1) ◽  
pp. 46-60 ◽  
Author(s):  
David J. Bentley ◽  
Veronica E. Vleck ◽  
Gregoire P. Millet
Keyword(s):  
Power Output ◽  
Average Power ◽  
Time Trial ◽  
Mechanical Efficiency ◽  
Incremental Test ◽  
Long Duration ◽  
Average Power Output ◽  
And Performance ◽  
The Relationship

The purpose of this study was to determine the relationship between the isocapnic buffer (βisocapnic) and hypocapnic hyperventilation (HHV) phases as well as performance in a short (20-min) and long (90-min) time trial (TT) in trained athletes. In addition, gross (GE, %) and delta (ΔE, %) efficiency were calculated and the relationship between these variables and the average power output (W) in each TT was determined. Thirteen male endurance athletes (Mean ± SD age 31 ± 6 yrs; body mass 75.6 ± 6.3 kg; height 185 ± 6 cm) completed a continuous incremental test to exhaustion for determination of the βisocapnic and HHV phases. A second submaximal test was used to determine GE and ΔE. The average power output (W) was measured in a 20-min and 90-min cycling TT. The βisocapnic phase (W) was significantly correlated to the average power output (W) in the 20-min TT (r = 0.58; p <  0.05), but not in the 90-min TT (r = 0.28). The HHV phase (W) was not significantly correlated to the average power output in the 20-min or 90-min TT. No significant correlation was found for GE or for ΔE and performance in the TT. The data from this study shows that βisocapnic together with HHV is not likely to be a useful indicator of cycle TT performance of 20- to 90-min duration. Furthermore, GE and ΔE determined from a submaximal incremental stepwise test are not related to cycling TT performance of different duration. Key words: incremental, correlation, metabolism, athletes, fatigue

Cycling Efficiency and Performance Following Short-Term Training Using Uncoupled Cranks

2009 ◽  
Vol 4 (1) ◽  
pp. 18-28 ◽  
Author(s):  
Andrew D. Williams ◽  
Isaac Selva Raj ◽  
Kristie L. Stucas ◽  
James W. Fell ◽  
Diana Dickenson ◽  
...  
Keyword(s):  
Lactate Threshold ◽  
Performance Enhancement ◽  
Average Power ◽  
Time Trial ◽  
Mechanical Efficiency ◽  
Cycling Performance ◽  
Peak Power Output ◽  
Gross Efficiency ◽  
And Performance ◽  
Study Participants

Objectives:Uncoupled cycling cranks are designed to remove the ability of one leg to assist the other during the cycling action. It has been suggested that training with this type of crank can increase mechanical efficiency. However, whether these improvements can confer performance enhancement in already well-trained cyclists has not been reported.Method:Fourteen well-trained cyclists (13 males, 1 female; 32.4 ± 8.8 y; 74.5 ± 10.3 kg; Vo2max 60.6 ± 5.5 mL·kg−1·min−1; mean ± SD) participated in this study. Participants were randomized to training on a stationary bicycle using either an uncoupled (n = 7) or traditional crank (n = 7) system. Training involved 1-h sessions, 3 days per week for 6 weeks, and at a heart rate equivalent to 70% of peak power output (PPO) substituted into the training schedule in place of other training. Vo2max, lactate threshold, gross efficiency, and cycling performance were measured before and following the training intervention. Pre- and post testing was conducted using traditional cranks.Results:No differences were observed between the groups for changes in Vo2max, lactate threshold, gross efficiency, or average power maintained during a 30-minute time trial.Conclusion:Our results indicate that 6 weeks (18 sessions) of training using an uncoupled crank system does not result in changes in any physiological or performance measures in well-trained cyclists.

Mood and Cycling Performance in Response to Three Weeks of High-Intensity, Short-Duration Overtraining, and a Two-Week Taper

1999 ◽  
Vol 13 (4) ◽  
pp. 444-457 ◽  
Author(s):  
Bonnie G. Berger ◽  
Robert W. Motl ◽  
Brian D. Butki ◽  
David T. Martin ◽  
John G. Wilkinson ◽  
...  
Keyword(s):  
Short Duration ◽  
Power Output ◽  
High Intensity ◽  
Average Power ◽  
Interval Training ◽  
The United States ◽  
Cycling Performance ◽  
Mood Disturbance ◽  
Average Power Output ◽  
And Performance

This study examined changes in mood and performance in response to high-intensity, short-duration overtraining and a subsequent taper. Pursuit cyclists (N = 8) at the United States Olympic Training Center completed the POMS and simulated 4-km pursuit performance tests throughout a six-week period. The six-week period included a baseline week, three weeks of overtraining that consisted primarily of high-intensity interval training, and a two-week taper. Total Mood Disturbance (TMD) scores displayed a quadratic polynomial effect across the three weeks of overtraining (p < .01), with the highest TMD scores occurring in the second week. Average TMD scores were lower during the taper than at baseline (p < .02) and lower at taper than overtraining (p < .0005). Cycling performance (pursuit time and average power output) improved during the three weeks of overtraining; additional improvements were observed during the taper. There were no significant correlations between TMD and performance. However, pursuit time, average power output, and mood disturbance scores were at optimal levels throughout the taper period. These findings suggest that high-intensity, short-duration overtraining may not result in an overtraining syndrome in 4-km pursuit cyclists.

Carbohydrate-Electrolyte Feedings and 1h Time Trial Cycling Performance

2004 ◽  
Vol 14 (5) ◽  
pp. 541-549 ◽  
Author(s):  
Ben Desbrow ◽  
Sally Anderson ◽  
Jennifer Barrett ◽  
Elissa Rao ◽  
Mark Hargreaves
Keyword(s):  
Power Output ◽  
High Intensity ◽  
Average Power ◽  
Time Trial ◽  
Cycling Performance ◽  
Dietary Regimen ◽  
Trained Subjects ◽  
Sports Drink ◽  
Average Power Output ◽  
Glucose Availability

The effects of a commercial sports drink on performance in high-intensity cycling was investigated. Nine well-trained subjects were asked to complete a set amount of work as fast as possible (time trial) following 24 h of dietary (subjects were provided with food, energy 57.4 ± 2.4 kcal/kg and carbohydrate 9.1 ± 0.4 g/kg) and exercise control. During exercise, subjects were provided with 14 mL/kg of either 6% carbohydrate-electrolyte (CHO-E) solution or carbohydrate-free placebo (P). Results showed that subjects’ performances did not greatly improve (time, 62:34 ± 6:44 min:sec (CHO-E) vs. 62:40 ± 5:35 min:sec (P); average power output, 283.0 ± 25.0 W (CHO-E) vs. 282.9 ± 29.3 W (P), P > 0.05) while consuming the sports drink. It was concluded that CHO-E consumption throughout a 1-h time trial, following a pre-exercise dietary regimen designed to optimize glucose availability, did not improve time or power output to a greater degree than P in well-trained cyclists.

The Influence of Blood Removal on Pacing During a 4-Minute Cycling Time Trial

2017 ◽  
Vol 12 (8) ◽  
pp. 1085-1092
Author(s):  
Nathan G. Lawler ◽  
Chris R. Abbiss ◽  
Aaron Raman ◽  
Timothy J. Fairchild ◽  
Garth L. Maker ◽  
...  
Keyword(s):  
Power Output ◽  
Average Power ◽  
Time Trial ◽  
Energy Contribution ◽  
Cycling Time Trial ◽  
Baseline Testing ◽  
Average Power Output ◽  
Rate Of Decline ◽  
Aerobic And Anaerobic ◽  
Cycling Time

Purpose:To examine the influence of manipulating aerobic contribution after whole-blood removal on pacing patterns, performance, and energy contribution during self-paced middle-distance cycling.Methods:Seven male cyclists (33 ± 8 y) completed an incremental cycling test followed 20 min later by a 4-min self-paced cycling time trial (4MMP) on 6 separate occasions over 42 d. The initial 2 sessions acted as familiarization and baseline testing, after which 470 mL of blood was removed, with the remaining sessions performed 24 h, 7 d, 21 d, and 42 d after blood removal. During all 4MMP trials, power output, oxygen uptake, and aerobic and anaerobic contribution to power were determined.Results:4MMP average power output significantly decreased by 7% ± 6%, 6% ± 8%, and 4% ± 6% at 24 h, 7 d, and 21 d after blood removal, respectively. Compared with baseline, aerobic contribution during the 4MMP was significantly reduced by 5% ± 4%, 4% ± 5%, and 4% ± 10% at 24 h, 7 d, and 21 d, respectively. The rate of decline in power output on commencement of the 4MMP was significantly attenuated and was 76% ± 20%, 72% ± 24%, and 75% ± 35% lower than baseline at 24 h, 21 d, and 42 d, respectively.Conclusion:Removal of 470 mL of blood reduces aerobic energy contribution, alters pacing patterns, and decreases performance during self-paced cycling. These findings indicate the importance of aerobic energy distribution during self-paced middle-distance events.

Difference in Pacing Between Time- and Distance-Based Time Trials in Trained Cyclists

2016 ◽  
Vol 11 (8) ◽  
pp. 1018-1023 ◽  
Author(s):  
Chris R. Abbiss ◽  
Kevin G. Thompson ◽  
Marcin Lipski ◽  
Tim Meyer ◽  
Sabrina Skorski
Keyword(s):  
Power Output ◽  
Perceived Exertion ◽  
Average Power ◽  
Ratings Of Perceived Exertion ◽  
Similar Time ◽  
Long Duration ◽  
Higher Power ◽  
Average Power Output ◽  
Rate Of Decline ◽  
Power Outputs

The purpose of this study was to compare the pacing profiles between distance- and duration-based trials of short and long duration. Thirteen trained cyclists completed 2 time-based (6 and 30 min) and 2 distance-based (4 and 20 km) self-paced cycling time trials. Participants were instructed to complete each trial with the highest average power output. Ratings of perceived exertion (RPEs) were measured throughout the trials. Average power output was not different between the 4-km and 6-min trials (324 ± 46 vs 325 ± 45 W; P = .96) or between the 20-km and 30-min trials (271 ± 44 vs 267 ± 38 W; P = .24). Power output was greater on commencement of the distance-based trials when short and long trials were analyzed together. Furthermore, the rate of decline in power output over the 1st 40% of the trial was greater in the 20-km trial than in the 30-min trial (P = .01) but not different between the 4-km and the 6-min trials (P = .13). RPE was greater in the 4-km trial than in the 6-min trial but not different between the 20-km and 30-min trials. These findings indicate that athletes commenced distance-based time trials at relatively higher power outputs than a similar time-based trial. Such findings may result from discrete differences in our ability to judge or predict an exercise endpoint when performing time- and distance-based trials.

Do Anxious Swimmers Swim Slower? Reexamining the Elusive Anxiety-Performance Relationship

1988 ◽  
Vol 10 (1) ◽  
pp. 45-61 ◽  
Author(s):  
Damon Burton
Keyword(s):  
Low Complexity ◽  
Performance Measure ◽  
Somatic Anxiety ◽  
Self Confidence ◽  
Cognitive Anxiety ◽  
Long Duration ◽  
Two Samples ◽  
And Performance ◽  
Moderate Complexity ◽  
The Relationship

The purpose of this investigation was to utilize a multidimensional measure of anxiety and a more sensitive intraindividual performance measure to evaluate the relationship between anxiety and performance. Three hypotheses were tested. First, cognitive anxiety is more consistently and strongly related to performance than is somatic anxiety. Second, somatic anxiety demonstrates an inverted-U relationship with performance, whereas self-confidence and performance exhibit a positive linear relationship and cognitive anxiety and performance exhibit a negative one. Finally, short duration and high and low complexity events demonstrate stronger relationships between somatic anxiety and performance than do long duration or moderate complexity events. Two samples of swimmers completed the CSAI-2 prior to competition, and performance data were obtained from meet results. Correlational and multiple regression analyses generally supported Hypotheses 1 and 3, while polynomial trend analyses on standardized CSAI-2 scores confirmed trends predicted in Hypothesis 2. Overall, these results not only revealed that improved instrumentation allows demonstration of consistent anxiety-performance relationships, but they also provided additional construct validity for the CSAI-2.

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.

scholarly journals The effect of low- vs high-cadence interval training on the freely chosen cadence and performance in endurance-trained cyclists

2016 ◽  
Vol 41 (6) ◽  
pp. 666-673 ◽  
Author(s):  
Anthony G. Whitty ◽  
Aron J. Murphy ◽  
Aaron J. Coutts ◽  
Mark L. Watsford
Keyword(s):  
Perceived Exertion ◽  
Average Power ◽  
Time Trial ◽  
Interval Training ◽  
Performance Measure ◽  
Rating Of Perceived Exertion ◽  
Superior Performance ◽  
Strength Development ◽  
And Performance ◽  
High Cadence

The aim of this study was to determine the effects of high- and low-cadence interval training on the freely chosen cadence (FCC) and performance in endurance-trained cyclists. Sixteen male endurance-trained cyclists completed a series of submaximal rides at 60% maximal power (Wmax) at cadences of 50, 70, 90, and 110 r·min−1, and their FCC to determine their preferred cadence, gross efficiency (GE), rating of perceived exertion, and crank torque profile. Performance was measured via a 15-min time trial, which was preloaded with a cycle at 60% Wmax. Following the testing, the participants were randomly assigned to a high-cadence (HC) (20% above FCC) or a low-cadence (LC) (20% below FCC) group for 18 interval-based training sessions over 6 weeks. The HC group increased their FCC from 92 to 101 r·min−1 after the intervention (p = 0.01), whereas the LC group remained unchanged (93 r·min−1). GE increased from 22.7% to 23.6% in the HC group at 90 r·min−1 (p = 0.05), from 20.0% to 20.9% at 110 r·min−1 (p = 0.05), and from 22.8% to 23.2% at their FCC. Both groups significantly increased their total distance and average power output following training, with the LC group recording a superior performance measure. There were minimal changes to the crank torque profile in both groups following training. This study demonstrated that the FCC can be altered with HC interval training and that the determinants of the optimal cycling cadence are multifactorial and not completely understood. Furthermore, LC interval training may significantly improve time-trial results of short duration as a result of an increase in strength development or possible neuromuscular adaptations.

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