319 research outputs found

    Caffeine and sprint cycling performance: effects of torque factor and sprint duration

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    Purpose: The aim of this study was to investigate the influence of torque factor and sprint duration on the effects of caffeine on sprint cycling performance. Methods: Using a counterbalanced, randomized, double-blind, placebo-controlled design, 13 men completed nine trials. In Trial 1, participants completed a series of 6 s sprints at increasing torque factors, to determine the torque factor, for each individual, which elicited the highest (TOPTIMAL) peak power output (PPO). The remaining trials involved all combinations of torque factor (0.8 N∙m∙kg-1 versus TOPTIMAL), sprint duration (10 s versus 30 s), and supplementation (caffeine [5mg∙kg-1] versus placebo). Results: There was a significant effect of torque factor on PPO, with higher values at TOPTIMAL (mean difference: 168 W; 95% likely range: 142 – 195 W). There was also a significant effect of sprint duration on PPO, with higher values in 10 s sprints (mean difference: 52 W; 95% likely range: 18 – 86 W). However, there was no effect of supplementation on PPO (p = 0.056). Nevertheless, there was a significant torque factor × sprint duration × supplement interaction (p = 0.036), with post hoc tests revealing that caffeine produced a higher PPO (mean difference: 76 W; 95% likely range: 19 – 133 W) when the sprint duration was 10 s and the torque factor was TOPTIMAL. Conclusions: The results of this study show that when torque factor and sprint duration are optimized, to allow participants to express their highest PPO, there is a clear effect of caffeine on sprinting performance

    Caffeine and Sprinting Performance: Dose Responses and Efficacy

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    The aims of this study were to evaluate the effects of caffeine supplementation on sprint cycling performance and to determine if there was a dose-response effect. Using a randomized, double-blind, placebo-controlled design, 17 well-trained men (age: 24 ± 6 years, height: 1.82 ± 0.06 m, and body mass(bm): 82.2 ± 6.9 kg) completed 7 maximal 10-second sprint trials on an electromagnetically braked cycle ergometer. Apart from trial 1 (familiarization), all the trials involved subjects ingesting a gelatine capsule containing either caffeine or placebo (maltodextrin) 1 hour before each sprint. To examine dose-response effects, caffeine doses of 2, 4, 6, 8, and 10 mg·kg bm−1 were used. There were no significant (p ≥ 0.05) differences in baseline measures of plasma caffeine concentration before each trial (grand mean: 0.14 ± 0.28 μg·ml−1). There was, however, a significant supplement × time interaction (p < 0.001), with larger caffeine doses producing higher postsupplementation plasma caffeine levels. In comparison with placebo, caffeine had no significant effect on peak power (p = 0.11), mean power (p = 0.55), or time to peak power (p = 0.17). There was also no significant effect of supplementation on pretrial blood lactate (p = 0.58), but there was a significant time effect (p = 0.001), with blood lactate reducing over the 50 minute postsupplementation rest period from 1.29 ± 0.36 to 1.06 ± 0.33 mmol·L−1. The results of this study show that caffeine supplementation has no effect on short-duration sprint cycling performance, irrespective of the dosage used

    Model of implementation of all-russian sports complex GTO in higher educational establishment in Sverdlovsk oblast: introduction of encouragement

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    В статье рассматривается система поощрений студентов, выполнивших на этапе обучения нормы ГТО

    The Effects of Caffeine Supplementation on Physiological Responses to Submaximal Exercise in Endurance-Trained Men

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    Copyright: © 2016 Glaister et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Objectives The aim of this study was to evaluate the effects of caffeine on physiological responses to submaximal exercise, with a focus on blood lactate concentration ([BLa]). Methods Using a randomised, single-blind, crossover design; 16 endurance-trained, male cyclists (age: 38 ± 8 years; height: 1.80 ± 0.05 m; body mass: 76.6 ± 7.8 kg; V_ O2max: 4.3 ± 0.6 Lmin-1) completed four trials on an electromagnetically-braked cycle ergometer. Each trial consisted of a six-stage incremental test (3 minute stages) followed by 30 minutes of passive recovery. One hour before trials 2–4, participants ingested a capsule containing 5 mgkg-1 of either caffeine or placebo (maltodextrin). Trials 2 and 3 were designed to evaluate the effects of caffeine on various physiological responses during exercise and recovery. In contrast, Trial 4 was designed to evaluate the effects of caffeine on [BLa] during passive recovery from an end-exercise concentration of 4 mmolL-1. Results Relative to placebo, caffeine increased [BLa] during exercise, independent of exercise intensity (mean difference: 0.33 ± 0.41 mmolL-1; 95% likely range: 0.11 to 0.55 mmolL-1), but did not affect the time-course of [BLa] during recovery (p = 0.604). Caffeine reduced ratings of perceived exertion (mean difference: 0.5 ± 0.7; 95% likely range: 0.1 to 0.9) and heart rate (mean difference: 3.6 ± 4.2 bmin-1; 95% likely range: 1.3 to 5.8 bmin-1) during exercise, with the effect on the latter dissipating as exercise intensity increased. Supplement × exercise intensity interactions were observed for respiratory exchange ratio (p = 0.004) and minute ventilation (p = 0.034). Conclusions The results of the present study illustrate the clear, though often subtle, effects of caffeine on physiological responses to submaximal exercise. Researchers should be aware of these responses, particularly when evaluating the physiological effects of various experimental interventions.Peer reviewedFinal Published versio

    Effects of dietary nitrate, caffeine, and their combination on 20-km cycling time trial performance.

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    This is the accepted manuscript version of the following article: M. Glaister, J. R. Pattison, D. Muniz-Pumares, S. D. Patterson, and P. Foley, “Effects of Dietary Nitrate, Caffeine, and Their Combination on 20-km Cycling Time Trial Performance”, The Journal of Strength and Conditioning Research,Vol. 29(1): 165-174, January 2015. The final published version is available at: http://journals.lww.com/nsca-jscr/Pages/aboutthejournal.aspx ©2015 by the National Strength & Conditioning Association.The aim of this study was to examine the acute supplementation effects of dietary nitrate, caffeine, and their combination on 20-km cycling time trial performance. Using a randomized, counterbalanced, double-blind Latin-square design, 14 competitive female cyclists (age: 31 ± 7 years; height: 1.69 ± 0.07 m; body mass: 61.6 ± 6.0 kg) completed four 20-km time trials on a racing bicycle fitted to a turbo trainer. Approximately 2.5 hours before each trial, subjects consumed a 70-ml dose of concentrated beetroot juice containing either 0.45 g of dietary nitrate or with the nitrate content removed (placebo). One hour before each trial, subjects consumed a capsule containing either 5 mg·kg of caffeine or maltodextrin (placebo). There was a significant effect of supplementation on power output (p = 0.001), with post hoc tests revealing higher power outputs in caffeine (205 ± 21 W) vs. nitrate (194 ± 22 W) and placebo (194 ± 25 W) trials only. Caffeine-induced improvements in power output corresponded with significantly higher measures of heart rate (caffeine: 166 ± 12 b·min vs. placebo: 159 ± 15 b·min; p = 0.02), blood lactate (caffeine: 6.54 ± 2.40 mmol·L vs. placebo: 4.50 ± 2.11 mmol·L; p < 0.001), and respiratory exchange ratio (caffeine: 0.95 ± 0.04 vs. placebo: 0.91 ± 0.05; p = 0.03). There were no effects (p ≥ 0.05) of supplementation on cycling cadence, rating of perceived exertion, (Equation is included in full-text article.), or integrated electromyographic activity. The results of this study support the well-established beneficial effects of caffeine supplementation on endurance performance. In contrast, acute supplementation with dietary nitrate seems to have no effect on endurance performance and adds nothing to the benefits afforded by caffeine supplementation.Peer reviewedFinal Accepted Versio

    Business models in rail infrastructure: explaining innovation

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    Policy decisions about the UK railway industry often draw on models and frameworks that treat technology and organisational processes as static and unchanging. As a result, policy makers often have limited understanding of how changes in policy will influence organisational knowledge, learning and the allocation of risk that subsequently affects innovation and system development. This paper applies a business model lens, focused on the mechanisms firms use to create and capture value, to connect policy decisions to subsequent changes in the organisation and industrial structure of the UK railway sector. By analysing innovation-related activity across several different governance structures, the paper highlights how policy impacts in network-based infrastructure sectors are mediated by business strategy, sometimes leading to unintended outcomes. The findings suggest that policy to improve the performance should focus upon coordination rather than just ownership. The application of a business model approach to complement existing economic and policy models in system analysis for policy decisions is advocated
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