Effects of coffee and caffeine anhydrous on strength and sprint performance     

Eric T. Trexler  Erica J. Roelofs  Katie R. Hirsch  Meredith G. Mock 《European Journal of Sport Science》2016,16(6):702-710

Caffeine and coffee are widely used among active individuals to enhance performance. The purpose of the current study was to compare the effects of acute coffee (COF) and caffeine anhydrous (CAF) intake on strength and sprint performance. Fifty-four resistance-trained males completed strength testing, consisting of one-rep max (1RM) and repetitions to fatigue (RTF) at 80% of 1RM for leg press (LP) and bench press (BP). Participants then completed five, 10-second cycle ergometer sprints separated by one minute of rest. Peak power (PP) and total work (TW) were recorded for each sprint. At least 48 hours later, participants returned and ingested a beverage containing CAF (300?mg flat dose; yielding 3–5?mg/kg bodyweight), COF (8.9?g; 303?mg caffeine), or placebo (PLA; 3.8?g non-caloric flavouring) 30 minutes before testing. LP 1RM was improved more by COF than CAF (p?=?.04), but not PLA (p?=?.99). Significant interactions were not observed for BP 1RM, BP RTF, or LP RTF (p?>?.05). There were no sprint?×?treatment interactions for PP or TW (p?>?.05). 95% confidence intervals revealed a significant improvement in sprint 1 TW for CAF, but not COF or PLA. For PLA, significant reductions were observed in sprint 4 PP, sprint 2 TW, sprint 4 TW, and average TW; significant reductions were not observed with CAF or COF. Neither COF nor CAF improved strength outcomes more than PLA, while both groups attenuated sprint power reductions to a similar degree. Coffee and caffeine anhydrous may be considered suitable pre-exercise caffeine sources for high-intensity exercise.  相似文献   

Effects of load mass carried in a backpack upon respiratory muscle fatigue     

Mark Faghy  Sam Blacker  Peter I. Brown 《European Journal of Sport Science》2016,16(8):1032-1038

Purpose: The purpose of this study was to investigate whether loads carried in a backpack, with a load mass ranging from 0 to 20?kg, causes respiratory muscle fatigue. Methods: Eight males performed four randomised load carriage (LC) trials comprising 60?min walking at 6.5?km?h^?1 wearing a backpack of either 0 (LC₀), 10 (LC₁₀), 15 (LC₁₅) or 20?kg (LC₂₀). Inspiratory (P_Imax) and expiratory (P_Emax) mouth pressures were assessed prior to and immediately following each trial. Pulmonary gas exchange, heart rate (HR), blood lactate and glucose concentration and perceptual responses were recorded during the first and final 60?s of each trial. Results: Group mean P_Imax and P_Emax were unchanged following 60-min load carriage in all conditions (p?>?.05). There was an increase over time in pulmonary gas exchange, HR and perceptions of effort relative to baseline measures during each trial (p?p?>?.05). Conclusions: These findings indicate that sub-maximal walking with no load or carrying 10, 15 or 20?kg in a backpack for up to 60?min does not cause respiratory muscle fatigue despite causing an increase in physiological, metabolic and perceptual parameters.  相似文献   

Remote ischaemic preconditioning shortens QT intervals during exercise in healthy subjects     

Maxime Caru  François Lalonde  Hugo Gravel  Chantal Daigle  François Tournoux  Vincent Jacquemet 《European Journal of Sport Science》2016,16(8):1005-1013

The protective action of remote ischaemic preconditioning (RIPC) has been demonstrated in the context of surgical interventions in cardiology. Application of RIPC to sports performance has been proposed, but its effect on the electrocardiogram (ECG) during exercise remains unknown. This exploratory study aims to measure the changes in ventricular repolarization observed during exercise following RIPC in healthy subjects. In an experimental randomized crossover study, 17 subjects underwent two bouts of constant load exercise tests at 75% and 115% of gas exchange threshold (GET). Prior to exercise, they were allocated to either control or RIPC intervention with four cycles of 5?min of ischaemia followed by 5?min of reperfusion. ECG was continuously recorded during the protocol. QT and RR intervals were measured every 30?s (on an average tracing of the preceding 10?s). Although the time course of RR intervals did not differ between the two interventions (p?=?.56 at 75% GET and p?=?.74 at 115% GET), a significant shortening of QT intervals (measured from Q onset to T end) was observed during exercise (mean?±?standard deviation of RIPC vs. control: ?32?±?19?ms at 75% GET (p?p?p?p?相似文献   

Organismic integration as a dynamic process: a systematic review of empirical studies on change in behavioral regulations in exercise in adults     

Anna Wasserkampf  Jens Kleinert 《International review of sport and exercise psychology》2016,9(1):65-95

In facilitating the adoption of exercise behavior, attention should be directed towards the dynamic nature of behavioral regulations. Organismic integration theory presents a suitable framework for investigating fluctuations in behavioral regulations. However, current results pertaining to this issue revealed mixed findings. The aim of this review is to examine the empirical literature on the dynamic nature of organismic integration theory in exercise settings over time in adults. A systematic review of English articles using PsycINFO, PsycARTICLES, ScienceDirect, and SPORTDiscus was conducted including keywords of organismic integration theory, longitudinal designs, change in behavioral regulations, and exercise. Findings are summarized through quantitative analysis of the evidence. Regarding autonomous regulations, steady increases in regulations are observable that originate within the first weeks and persist for up to one year. Most studies reported no changes in controlled regulations, although in a few cases changes were observed six weeks after baseline or later. The review adds to the theoretical understanding of how behavioral regulations are internalized. However, whether changes in regulation occur depends on both the type of regulation and on contextual characteristics. Future research of longitudinal design is warranted to identify optimal periods in which individuals seek for increased support during exercise adoption.  相似文献   

浅析消除运动性疲劳的措施     

朱红香 《周口师范学院学报》2001,18(2):82-83

从生理学角度，用系统论的观点，论述了消除运动性疲劳的几种措施.  相似文献   

幼儿体育活动应注意的几个问题     

肖波  梅敏 《赣南师范学院学报》2007,28(6):95-97

幼儿体育活动不但是学前教育研究的一个课题,同时也是体育教育研究的一个方向.在阐明幼儿生理特点的基础上,对幼儿体育活动兴趣的培养,幼儿体育活动量化,幼儿体育活动中的卫生与安全分别进行了探讨,为完善我国幼儿健康教育提供参考.  相似文献   

背越式跳高中助跑与起跳结合的重要性     

孙玲娜 《宁德师专学报(自然科学版)》2007,19(3):249-251

背越式跳高中助跑与起跳的紧密结合对跳高成绩起着十分重要的作用．通过运动力学、解剖学分析和动作技能形成过程中的心理特点分析，对助跑起跳学习环节加大重视，多做有关的辅助练习，形成正确规范的技术动作，有助于学生更快更好地提高运动成绩．  相似文献   

高师院校学生课外体育锻炼现状的调查分析     

张丽玉  钟庆春 《嘉应学院学报》2002,20(6):114-117

运用文献资料研究法、问卷调查法、数理统计法,对韩山师范学院普通专业学生参加课外体育锻炼的现状进行调查分析,旨在了解学生参与课外体育锻炼的现状与存在问题,并提出改革的措施。  相似文献   

数学技能教与学的若干思考   总被引：2，自引：2，他引：2  

季素月 《数学教育学报》2003,12(2):27-30

有3个因素影响着数学技能的掌握与类化，这就是知识的理解水平，练习的感悟水平和认知策略的迁移水平，而传统的技能学习在这几方面均存在问题．随着课程改革的不断深入，除了重新认识数学技能的内涵外，还须改进数学技能的教学观念与方式，比如，控制训练的量与度，在变式训练的同时引导学生感悟、反思，让学生自我体会数学思想方法等．  相似文献   

中美语文教材练习设计的比较与思考          下载免费PDF全文

欧治华 《惠州学院学报》2007,27(5):117-121

完善语文教材的编写需要开拓视野，借鉴反思，不断创新。在归纳中美语文教材练习设计的共同点基础上，从两国对练习所起作用的认识、练习与选文的处理方式、序列性的体现程度以及练习指导策略等方面加以比较分析，找出差异，进而提出改进我国课后练习设计的具体策略。  相似文献