scholarly journals Reproducibility of cardiorespiratory and cellular responses to steady state exercise in hypoxia and preloaded cycling time trial performance reliability in normoxia and acute hypoxia

2015 ◽  
Author(s):  
Ben J Lee ◽  
Charles D Thake
Keyword(s):  
Stress Test ◽  
Acute Hypoxia ◽  
Correlation Coefficients ◽  
Time Trial ◽  
Cellular Responses ◽  
Time Of Day ◽  
Cycling Time Trial ◽  
Hypoxic Conditions ◽  
Before And After ◽  
Cycling Time

Background. The purpose of this study was to assess the reproducibility of cardiorespiratory and cellular (monocyte heat shock protein 70; mHSP70) responses to a fixed load hypoxic stress test (HST) and the reliability of a pre-loaded 16.1km cycling time trial (pTT) conducted under both normoxic and hypoxic conditions. Methods. Eighteen participants (age, 22 ± 4 years; height, 1.77 ± 0.04 meters; body mass, 76.8 kg; estimated body fat and VO2peak = 3.50 ± 0.60 L.min-1) were divided into three groups. Reliability of responses (HR, SPO2, VO2, VCO2, VE and RER) to the HST (FIO2 0.14; 15 minutes rest, 60 minutes cycling at 50% normoxic VO2peak) was assessed across 3 repeat trials (HST 1, 2 and 3, n = 6); mHSP70 was measured via flow cytometry before and after each HST (n = 5); resting HSP was also quantified on 4 separate occasions (n=5). Reliability of the pTT (15 min rest, 40 minutes cycling at 50% normoxic VO2peak) was assessed across 3 repeat normoxic (N; FIO2 ≈ 0.21; n=6) and 3 repeat hypoxic (FIO2 ≈ 0.14; n = 6) trials. All exercise trials were undertaken at the same time of day, following exercise and dietary controls, 7 days apart. Results. Intra-class correlation coefficients (ICC’s) for mean and peak HR, SpO2, VE , VO2 , VCO2 and BLa within each trial were improved from HST1 to HST2 (mean data: 0.99, 0.95, 0.75, 0.62, 0.70, 0.90; peak data: 0.98, 0.96, 0.64, 0.69, 0.74, 0.75) to HST2 and HST3 (ICC = 0.99, 0.97, 0.82, 0.85, 0.87 and 0.96 respectively). mHSP70 was a reproducible at rest without (ICC > 0.95) and with HSTs conducted in the previous 7 days (ICC > 0.95), with no difference in pre to post increases in mHSP70 observed between tests. The reliability for time to pTT completion was improved following one trial, and the CV (test 2 vs. 3) was similar under normoxic (CV = 0.62) and hypoxic conditions (CV = 0.63). Conclusion. Cardiorespiratory and cellular responses to the HST were reproducible and the pTT performance time reliable in both N and H. Since the reproducibility of the measurements in HST trials and reliability of pTT improved between the second and third trials one familiarization visit is recommended prior to employing these protocols in future studies.

Time of day has no influence on performance and pacing during a 4km cycling time trial

2017 ◽  
Vol 20 ◽  
pp. e86-e87
Author(s):  
E. Zadow ◽  
C. Kitic ◽  
S. Wu ◽  
C. Abbiss ◽  
J. Peiffer ◽  
...  
Keyword(s):  
Time Trial ◽  
Time Of Day ◽  
Cycling Time Trial ◽  
Cycling Time

scholarly journals Reproducibility of cardiorespiratory and performance responses to exercise in hypoxia

2016 ◽  
Author(s):  
Ben J Lee ◽  
Charles D Thake
Keyword(s):  
Performance Measures ◽  
Correlation Coefficients ◽  
Time Trial ◽  
Time Of Day ◽  
Intra Class Correlation ◽  
Future Studies ◽  
Performance Time ◽  
Hypoxic Conditions ◽  
And Performance ◽  
Hypoxic Exercise

Background. Knowledge of the variance in physiological performance measures between repeated trials can inform whether familiarization sessions are necessary prior to intervention studies. The purpose of this study was to assess the reliability of cardiorespiratory and exercise performance measures during both steady state hypoxic exercise and a preloaded 16.1 km hypoxic time trial. Methods. Eighteen male participants (age, 22 ± 4 years; height, 1.77 ± 0.04 meters; body mass, 76.8 kg; estimated body fat and VO2peak = 3.50 ± 0.60 L.min-1) were divided into three groups. Reliability of responses (HR, SPO2 , VO2 , VCO2 , VE and respiratory exchange ratio; RER) to the HST (FIO2 0.14; 15 minutes rest, 60 minutes cycling at 50% normoxic VO2peak) was assessed across 3 repeat trials (HST 1, 2 and 3, n = 6). Reliability of the preloaded time trial (pTT; 15 min rest, 40 minutes cycling at 50% normoxic VO2peak, 16.1km time trial) was assessed across 3 repeat normoxic (N; FIO2 ≈ 0.21; n=6) and 3 repeat hypoxic (FIO2 ≈ 0.14; n = 6) trials. All exercise trials were undertaken at the same time of day, following exercise and dietary controls, 7 days apart. Results. Intra-class correlation coefficients (ICC’s) for mean and peak HR, SpO2 , VE , VO2 , VCO2 and blood lactate within each trial were improved from HST1 to HST2 (mean data: 0.99, 0.95, 0.75, 0.62, 0.70, 0.90; peak data: 0.98, 0.96, 0.64, 0.69, 0.74, 0.75) to HST2 and HST3 (ICC = 0.99, 0.97, 0.82, 0.85, 0.87 and 0.96 respectively). The reliability for time to pTT completion was improved following one trial, and the CV (test 2 vs. 3) was similar under normoxic (CV = 0.62) and hypoxic conditions (CV = 0.63). Conclusion. Cardiorespiratory responses to the HST were reproducible and the pTT performance time reliable in both normoxia and hypoxia. Since the reproducibility of the measurements in HST trials and reliability of pTT improved between the second and third trials, two familiarization visit are recommended prior to employing these protocols in future studies.

scholarly journals Effect of Time of Day on Performance, Hormonal and Metabolic Response during a 1000-M Cycling Time Trial

PLoS ONE ◽  
2014 ◽  
Vol 9 (10) ◽  
pp. e109954 ◽  
Author(s):  
Alan Lins Fernandes ◽  
João Paulo Lopes-Silva ◽  
Rômulo Bertuzzi ◽  
Dulce Elena Casarini ◽  
Danielle Yuri Arita ◽  
...  
Keyword(s):  
Metabolic Response ◽  
Time Trial ◽  
Time Of Day ◽  
Cycling Time Trial ◽  
Cycling Time

scholarly journals Reproducibility of cardiorespiratory and performance responses to exercise in hypoxia

2016 ◽  
Author(s):  
Ben J Lee ◽  
Charles D Thake
Keyword(s):  
Performance Measures ◽  
Correlation Coefficients ◽  
Time Trial ◽  
Time Of Day ◽  
Intra Class Correlation ◽  
Future Studies ◽  
Performance Time ◽  
Hypoxic Conditions ◽  
And Performance ◽  
Hypoxic Exercise

Background. Knowledge of the variance in physiological performance measures between repeated trials can inform whether familiarization sessions are necessary prior to intervention studies. The purpose of this study was to assess the reliability of cardiorespiratory and exercise performance measures during both steady state hypoxic exercise and a preloaded 16.1 km hypoxic time trial. Methods. Eighteen male participants (age, 22 ± 4 years; height, 1.77 ± 0.04 meters; body mass, 76.8 kg; estimated body fat and VO2peak = 3.50 ± 0.60 L.min-1) were divided into three groups. Reliability of responses (HR, SPO2 , VO2 , VCO2 , VE and respiratory exchange ratio; RER) to the HST (FIO2 0.14; 15 minutes rest, 60 minutes cycling at 50% normoxic VO2peak) was assessed across 3 repeat trials (HST 1, 2 and 3, n = 6). Reliability of the preloaded time trial (pTT; 15 min rest, 40 minutes cycling at 50% normoxic VO2peak, 16.1km time trial) was assessed across 3 repeat normoxic (N; FIO2 ≈ 0.21; n=6) and 3 repeat hypoxic (FIO2 ≈ 0.14; n = 6) trials. All exercise trials were undertaken at the same time of day, following exercise and dietary controls, 7 days apart. Results. Intra-class correlation coefficients (ICC’s) for mean and peak HR, SpO2 , VE , VO2 , VCO2 and blood lactate within each trial were improved from HST1 to HST2 (mean data: 0.99, 0.95, 0.75, 0.62, 0.70, 0.90; peak data: 0.98, 0.96, 0.64, 0.69, 0.74, 0.75) to HST2 and HST3 (ICC = 0.99, 0.97, 0.82, 0.85, 0.87 and 0.96 respectively). The reliability for time to pTT completion was improved following one trial, and the CV (test 2 vs. 3) was similar under normoxic (CV = 0.62) and hypoxic conditions (CV = 0.63). Conclusion. Cardiorespiratory responses to the HST were reproducible and the pTT performance time reliable in both normoxia and hypoxia. Since the reproducibility of the measurements in HST trials and reliability of pTT improved between the second and third trials, two familiarization visit are recommended prior to employing these protocols in future studies.

Acute Prior Heavy Strength Exercise Bouts Improve the 20-km Cycling Time Trial Performance

2014 ◽  
Vol 28 (9) ◽  
pp. 2513-2520 ◽  
Author(s):  
Renato A.S. Silva ◽  
Fernando L. Silva-Júnior ◽  
Fabiano A. Pinheiro ◽  
Patrícia F.M. Souza ◽  
Daniel A. Boullosa ◽  
...  
Keyword(s):  
Time Trial ◽  
Strength Exercise ◽  
Time Trial Performance ◽  
Cycling Time Trial ◽  
Cycling Time ◽  
Trial Performance

Changes in drive phase lower limb kinematics during a 60min cycling time trial

2012 ◽  
Vol 15 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Mark G.L. Sayers ◽  
Amanda L. Tweddle ◽  
Joshua Every ◽  
Aaron Wiegand
Keyword(s):  
Lower Limb ◽  
Time Trial ◽  
Cycling Time Trial ◽  
Limb Kinematics ◽  
Lower Limb Kinematics ◽  
Cycling Time

Practical precooling: Effect on cycling time trial performance in warm conditions

2008 ◽  
Vol 26 (14) ◽  
pp. 1477-1487 ◽  
Author(s):  
Marc J. Quod ◽  
David T. Martin ◽  
Paul B. Laursen ◽  
Andrew S. Gardner ◽  
Shona L. Halson ◽  
...  
Keyword(s):  
Time Trial ◽  
Time Trial Performance ◽  
Cycling Time Trial ◽  
Cycling Time ◽  
Trial Performance

Cycling time trial performance during different phases of the menstrual cycle

2005 ◽  
Vol 94 (3) ◽  
pp. 268-276 ◽  
Author(s):  
Tanja Oosthuyse ◽  
Andrew N. Bosch ◽  
Susan Jackson
Keyword(s):  
Menstrual Cycle ◽  
Time Trial ◽  
Time Trial Performance ◽  
Cycling Time Trial ◽  
Cycling Time ◽  
Trial Performance

Beneficial Effects of Ice Ingestion as a Precooling Strategy on 40-km Cycling Time-Trial Performance

2010 ◽  
Vol 5 (2) ◽  
pp. 140-151 ◽  
Author(s):  
Mohammed Ihsan ◽  
Grant Landers ◽  
Matthew Brearley ◽  
Peter Peeling
Keyword(s):  
Perceived Exertion ◽  
Thermal Sensation ◽  
Tap Water ◽  
Time Trial ◽  
Cycle Ergometer ◽  
Time Trial Performance ◽  
Cycling Time Trial ◽  
Crushed Ice ◽  
Cycling Time ◽  
Trial Performance

Purpose:The effect of crushed ice ingestion as a precooling method on 40-km cycling time trial (CTT) performance was investigated.Methods:Seven trained male subjects underwent a familiarization trial and two experimental CTT which were preceded by 30 min of either crushed ice ingestion (ICE) or tap water (CON) consumption amounting to 6.8 g⋅kg-1 body mass. The CTT required athletes to complete 1200 kJ of work on a wind-braked cycle ergometer. During the CTT, gastrointestinal (Tgi) and skin (Tsk) temperatures, cycling time, power output, heart rate (HR), blood lactate (BLa), ratings of perceived exertion (RPE) and thermal sensation (RPTS) were measured at set intervals of work.Results:Precooling lowered the Tgi after ICE significantly more than CON (36.74 ± 0.67°C vs 37.27 ± 0.24°C, P < .05). This difference remained evident until 200 kJ of work was completed on the bike (37.43 ± 0.42°C vs 37.64 ± 0.21°C). No significant differences existed between conditions at any time point for Tsk, RPE or HR (P > .05). The CTT completion time was 6.5% faster in ICE when compared with CON (ICE: 5011 ± 810 s, CON: 5359 ± 820 s, P < .05).Conclusions:Crushed ice ingestion was effective in lowering Tgi and improving subsequent 40-km cycling time trial performance. The mechanisms for this enhanced exercise performance remain to be clarified.

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