Reproducibility of the Cycling Time to Exhaustion at in Highly Trained Cyclists

2003 ◽  
Vol 28 (4) ◽  
pp. 605-615 ◽  
Author(s):  
Paul B. Laursen ◽  
Cecilia M. Shing ◽  
David G. Jenkins
Keyword(s):  
Aerobic Power ◽  
Cycling Performance ◽  
Peak Oxygen Uptake ◽  
Time To Exhaustion ◽  
Subject Variability ◽  
Progressive Exercise ◽  
Two Measures ◽  
The Mean ◽  
Cycling Time ◽  
Within Subject Variability

The purpose of the present study was to examine, in highly trained cyclists, the reproducibility of cycling time to exhaustion (Tmax) at the power output equal to that attained at peak oxygen uptake ([Formula: see text]) during a progressive exercise test. Forty-three highly trained male cyclists (M ± SD; age = 25 + 6 yrs; weight = 75 ± 7 kg; [Formula: see text] = 64.8 ± 5.2 mlùkg−1•min−1) performed two Tmax tests one week apart. While the two measures of Tmax were strongly related (r = 0.884; p < 0.001), Tmax from the second test (245 ± 57 s) was significantly higher than that of the first (237 ± 57 s; p = 0.047; two-tailed). Within-subject variability in the present study was calculated to be 6 ± 6%, which was lower than that previously reported for Tmax in sub-elite runners (25%). The mean Tmax was significantly (p < 0.05) related to both the second ventilatory turnpoint (VT2; r = 0.38) and to [Formula: see text] (r = 0.34). Despite a relatively low within-subject coefficient of variation, these data demonstrate that the second score in a series of two Tmax tests may be significantly greater than the first. Moreover, the present data show that Tmax in highly trained cyclists is moderately related to VT2 and [Formula: see text]Key words: maximal aerobic power, endurance, fatigue, anaerobic threshold, cycling performance

Ischemic Preconditioning: Improved Cycling Performance Despite Nocebo Expectation

2020 ◽  
Vol 15 (3) ◽  
pp. 354-360 ◽  
Author(s):  
Christian P. Cheung ◽  
Joshua T. Slysz ◽  
Jamie F. Burr
Keyword(s):  
Ischemic Preconditioning ◽  
Aerobic Power ◽  
Lactate Concentration ◽  
Cycling Performance ◽  
Cycle Ergometer ◽  
Time To Exhaustion ◽  
Performance Expectations ◽  
Sham Treatment ◽  
Positive Expectation ◽  
Placebo Controls

Purpose: Ischemic preconditioning (IPC) through purposeful circulatory occlusion may enhance exercise performance. The value of IPC for improving performance is controversial owing to challenges with employing effective placebo controls. This study examines the efficacy of IPC versus a deceptive sham protocol for improving performance to determine whether benefits of IPC are attributable to true physiological effects. It was hypothesized that IPC would favorably alter performance more than a sham treatment and that physiological responses to exercise would be affected only after IPC treatment. Methods: In a randomized order, 16 participants performed incremental exercise to exhaustion on a cycle ergometer in control conditions and after sham and IPC treatments. Participants rated their belief as to the efficacy of each treatment compared with control. Results: Time to exhaustion was greatest after IPC (control = 1331 [270] s, IPC = 1429 [300] s, sham = 1343 [255] s, P = .02), despite negative performance expectations after IPC and positive expectation after sham. Maximal aerobic power remained unchanged after both SHAM and IPC (control = 42.0 [5.2], IPC = 41.7 [5.5], sham = 41.6 [5.5] mL·kg−1·min−1, P = .7), as did submaximal lactate concentration (control = 8.9 [2.6], sham = 8.0 [1.9], IPC = 7.7 [2.1] mmol, P = .1) and oxygen uptake (control = 37.8 [4.8], sham = 37.5 [5.3], IPC = 37.5 [5.5] mL·kg−1·min−1, P = .6). Conclusions: IPC before cycling exercise provides an ergogenic benefit that is not attributable to a placebo effect from positive expectation and that was not explained by traditionally suggested mechanisms.

scholarly journals Intra-individual variation of basal metabolic rate and the influence of daily habitual physical activity before testing

2003 ◽  
Vol 90 (2) ◽  
pp. 419-423 ◽  
Author(s):  
Mirjam P. E. Adriaens ◽  
Paul F. M. Schoffelen ◽  
Klaas R. Westerterp
Keyword(s):  
Physical Activity ◽  
Basal Metabolic Rate ◽  
Individual Variation ◽  
Repeated Measures ◽  
Regular Function ◽  
Habitual Physical Activity ◽  
Fasting State ◽  
Subject Variability ◽  
The Mean ◽  
Within Subject Variability

The present study determined the intra-individual variation of BMR measurements, using a standard out-patient protocol, with the subjects transporting themselves to the laboratory for the BMR measurements after spending the night at home. The effect of a non-fasting state and variation in daily habitual physical activity the day before testing was evaluated. Eight male and eleven female subjects participated in three BMR measurements with 2-week intervals. Physical activity was estimated with a tri-axial accelerometer for movement registration, during the 3 d before each BMR measurement. There were no significant differences in estimated BMR (ANOVA repeated measures, P=0·88) and in physical activity (ANOVA repeated measures, P=0·21). Mean within-subject CV in BMR was found to be 3·3 (SD 2·1) %, ranging from 0·4 to 7·2 %. Differences between BMR measurements could not be explained by differences in physical activity the day before; however the mean within-subject CV in BMR changed from 5·7 to 5·2 % after correcting for within-machine variability and from 5·2 to 3·3 % after excluding five measurements because of non-compliance to the protocol including fasting. In conclusion, BMR values measured with a standard out-patient protocol are sufficiently reproducible for most practical purposes despite the within-subject variability in physical activity the day before the measurement. For this purpose, however, non-fasting subjects must be excluded and a regular function check of the ventilated-hood system is recommendable.

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.

Within-Subject Variability in Ingratiation as a Function of Self-Esteem and Time

2019 ◽  
Vol 18 (4) ◽  
pp. 216-226
Author(s):  
Katharina Schmitte ◽  
Bert Schreurs ◽  
Mien Segers ◽  
I. M. “Jim” Jawahar
Keyword(s):  
Individual Differences ◽  
Small Group ◽  
Self Esteem ◽  
Random Coefficient ◽  
Person Perspective ◽  
Authority Figure ◽  
Subject Variability ◽  
Over Time ◽  
Within Subject Variability

Abstract. Adopting a within-person perspective, we theorize why ingratiation use directed toward an authority figure increases over time and for whom. We posit that as the appraisal event draws closer, the salience of achieving good evaluations increases, leading to an increasing use of ingratiation. We further propose that the increase will be stronger for individuals with low relative to high self-esteem. Participants were 349 students enrolled in a small-group, tutor-led management course. Data were collected in three bi-weekly waves and analyzed using random coefficient modeling. Results show that ingratiation use increased as time to the evaluation decreased, and low self-esteem students ingratiated more as time progressed. We conclude that ingratiation use varies as a function of contextual and inter-individual differences.

EEG neurofeedback improves cycling time to exhaustion

2021 ◽  
Vol 55 ◽  
pp. 101944
Author(s):  
Francesca Mottola ◽  
Anthony Blanchfield ◽  
James Hardy ◽  
Andrew Cooke
Keyword(s):  
Time To Exhaustion ◽  
Eeg Neurofeedback ◽  
Cycling Time

scholarly journals Physiological responses and cycle characteristics during double-poling versus diagonal-stride roller-skiing in junior cross-country skiers

2021 ◽  
Author(s):  
Erik P. Andersson ◽  
Irina Hämberg ◽  
Paulo Cesar Do Nascimento Salvador ◽  
Kerry McGawley
Keyword(s):  
Oxygen Uptake ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Peak Oxygen Uptake ◽  
Submaximal Exercise ◽  
Rating Of Perceived Exertion ◽  
Time To Exhaustion ◽  
Double Poling ◽  
Cross Country

Abstract Purpose This study aimed to compare physiological factors and cycle characteristics during cross-country (XC) roller-skiing at matched inclines and speeds using the double-poling (DP) and diagonal-stride (DS) sub-techniques in junior female and male XC skiers. Methods Twenty-three well-trained junior XC skiers (11 women, 12 men; age 18.2 ± 1.2 yr.) completed two treadmill roller-skiing tests in a randomized order using either DP or DS. The exercise protocols were identical and included a 5 min warm-up, 4 × 5 min submaximal stages, and an incremental test to exhaustion, all performed at a 5° incline. Results No significant three-way interactions were observed between sex, submaximal exercise intensity, and sub-technique. For the pooled sample, higher values were observed for DP versus DS during submaximal exercise for the mean oxygen uptake kinetics response time (33%), energy cost (18%), heart rate (HR) (9%), blood lactate concentration (5.1 versus 2.1 mmol·L−1), rating of perceived exertion (12%), and cycle rate (25%), while cycle length was lower (19%) (all P < 0.001). During the time-to-exhaustion (TTE) test, peak oxygen uptake ($$\dot{V}$$ V ˙ O2peak), peak HR, and peak oxygen pulse were 8%, 2%, and 6% lower, respectively, for DP than DS, with a 29% shorter TTE during DP (pooled data, all P < 0.001). Conclusion In well-trained junior XC skiers, DP was found to exert a greater physiological load than DS during uphill XC roller-skiing at submaximal intensities. During the TTE test, both female and male athletes were able to ski for longer and reached markedly higher $$\dot{V}$$ V ˙ O2peak values when using DS compared to DP.

scholarly journals Importance of between and within Subject Variability in Extracellular Vesicle Abundance and Cargo when Performing Biomarker Analyses

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 485
Author(s):  
Lauren A. Newman ◽  
Alia Fahmy ◽  
Michael J. Sorich ◽  
Oliver G. Best ◽  
Andrew Rowland ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Drug Exposure ◽  
Extracellular Vesicle ◽  
The Novel ◽  
Protein Markers ◽  
Diurnal Variability ◽  
Normal Ranges ◽  
Sampling Protocols ◽  
Subject Variability ◽  
Within Subject Variability

Small extracellular vesicles (sEV) have emerged as a potential rich source of biomarkers in human blood and present the intriguing potential for a ‘liquid biopsy’ to track disease and the effectiveness of interventions. Recently, we have further demonstrated the potential for EV derived biomarkers to account for variability in drug exposure. This study sought to evaluate the variability in abundance and cargo of global and liver-specific circulating sEV, within (diurnal) and between individuals in a cohort of healthy subjects (n = 10). We present normal ranges for EV concentration and size and expression of generic EV protein markers and the liver-specific asialoglycoprotein receptor 1 (ASGR1) in samples collected in the morning and afternoon. EV abundance and cargo was generally not affected by fasting, except CD9 which exhibited a statistically significant increase (p = 0.018). Diurnal variability was observed in the expression of CD81 and ASGR1, which significantly decreased (p = 0.011) and increased (p = 0.009), respectively. These results have potential implications for study sampling protocols and normalisation of biomarker data when considering the expression of sEV derived cargo as a biomarker strategy. Specifically, the novel finding that liver-specific EVs exhibit diurnal variability in healthy subjects should have broad implications in the study of drug metabolism and development of minimally invasive biomarkers for liver disease.

The effects of forward rotation of posture on computer-simulated 4-km track cycling: Implications of Union Cycliste Internationale rule 1.3.013.

2016 ◽  
Vol 231 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Oliver Caddy ◽  
William Fitton ◽  
Digby Symons ◽  
Anthony Purnell ◽  
Dan Gordon
Keyword(s):  
Standard Deviation ◽  
Cycling Performance ◽  
Frontal Surface ◽  
Integration Model ◽  
Power Profile ◽  
Fixed Power ◽  
Legal Position ◽  
The Mean ◽  
Forward Integration ◽  
Track Cycling

The aim of this research was to indicate improvements in 4-km cycling performance that may be gained as a function of reduced frontal surface area ( A) when Union Cycliste Internationale rule 1.3.013 is contravened. In 10 male cyclists age 26 ± 2 (mean ± standard deviation) years, height 180 ± 5 cm and body mass 71 ± 6 kg, entire cycling posture was rotated forward from where the nose of the saddle was 6 cm rearward of the bottom bracket spindle (P6) to 4, 2 and 0 cm (P4, P2 and P0); contravening Union Cycliste Internationale rule 1.3.013. Using computerised planimetry, A was estimated and a forward integration model was compiled to simulate 4-km track cycling end time ( T4km) when a fixed power profile was applied. At P2, there was a significant but non-meaningful reduction compared to P6 ( p < 0.05, d < 0.02). There were small but significant reductions in A and T4km between P6 and P0; −0.007 ± 0.004 m2 and −1.40 ± 0.73 s, respectively ( p < 0.001, d = −0.259). There were no significant differences between P4 and P6 for A and T4km. These results suggest that at the most forward position (P0), a small but significant increase in 4-km performance can be expected compared to the legal position (P6). Moreover, the mean difference in T4km between P6 and P0 is greater than the winning margin at the Union Cycliste Internationale 4-km pursuit world championships four times in the previous 10 years.

A Systematic Review of Submaximal Cycle Tests to Predict, Monitor, and Optimize Cycling Performance

2016 ◽  
Vol 11 (6) ◽  
pp. 707-714 ◽  
Author(s):  
Benoit Capostagno ◽  
Michael I. Lambert ◽  
Robert P. Lamberts
Keyword(s):  
Heart Rate ◽  
Power Output ◽  
Perceived Exertion ◽  
Heart Rate Recovery ◽  
Mechanical Efficiency ◽  
Cycling Performance ◽  
Rating Of Perceived Exertion ◽  
Time To Exhaustion ◽  
Gross Mechanical Efficiency ◽  
Multiple Variables

Finding the optimal balance between high training loads and recovery is a constant challenge for cyclists and their coaches. Monitoring improvements in performance and levels of fatigue is recommended to correctly adjust training to ensure optimal adaptation. However, many performance tests require a maximal or exhaustive effort, which reduces their real-world application. The purpose of this review was to investigate the development and use of submaximal cycling tests that can be used to predict and monitor cycling performance and training status. Twelve studies met the inclusion criteria, and 3 separate submaximal cycling tests were identified from within those 12. Submaximal variables including gross mechanical efficiency, oxygen uptake (VO2), heart rate, lactate, predicted time to exhaustion (pTE), rating of perceived exertion (RPE), power output, and heart-rate recovery (HRR) were the components of the 3 tests. pTE, submaximal power output, RPE, and HRR appear to have the most value for monitoring improvements in performance and indicate a state of fatigue. This literature review shows that several submaximal cycle tests have been developed over the last decade with the aim to predict, monitor, and optimize cycling performance. To be able to conduct a submaximal test on a regular basis, the test needs to be short in duration and as noninvasive as possible. In addition, a test should capture multiple variables and use multivariate analyses to interpret the submaximal outcomes correctly and alter training prescription if needed.

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