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   

Body composition of female road and track endurance cyclists: Normative values and typical changes     

Eric C. Haakonssen  Martin Barras  Louise M. Burke  David G. Jenkins  David T. Martin 《European Journal of Sport Science》2016,16(6):645-653

The aims of this study were to describe normative values and seasonal variation of body composition in female cyclists comparing female road and track endurance cyclists, and to validate the use of anthropometry to monitor lean mass changes. Anthropometric profiles (seven site skinfolds) were measured over 16 years from 126 female cyclists. Lean mass index (LMI) was calculated as body weight?×?skinfolds^?x. The exponent (x) was calculated as the slope of the natural logarithm of body weight and skinfolds. Percentage changes in LMI were compared to lean mass changes measured using dual-energy X-ray absorptiometry (DXA) in a subset of 25 road cyclists. Compared to sub-elite and elite cyclists, world class cyclists were (mean [95% CI]) 1.18?kg [0.46, 1.90] and 0.60?kg [0.05, 1.15] lighter and had skinfolds that were 7.4?mm [3.8, 11.0] and 4.6?mm [1.8, 7.4] lower, respectively. Body weight (0.41?kg [0.04, 0.77]) and skinfolds (4.0?mm [2.1, 6.0]) were higher in the off-season compared to the early-season. World class female road cyclists had lower body weight (6.04?kg [2.73, 9.35]) and skinfolds (11.5?mm [1.1, 21.9]) than track endurance cyclists. LMI (mean exponent 0.15 [0.13, 0.18]) explained 87% of the variance in DXA lean mass. In conclusion, higher performing female cyclists were lighter and leaner than their less successful peers, road cyclists were lighter and leaner than track endurance cyclists, and weight and skinfolds were lowest early in the season. LMI appears to be a reasonably valid tool for monitoring lean mass changes.  相似文献   

Sex-specific associations of moderate and vigorous physical activity with physical fitness in adolescents     

T. Kidokoro  H. Tanaka  K. Naoi  K. Ueno  T. Yanaoka  K. Kashiwabara 《European Journal of Sport Science》2016,16(8):1159-1166

The present study examined the sex-specific associations of moderate and vigorous physical activity (VPA) with physical fitness in 300 Japanese adolescents aged 12–14 years. Participants were asked to wear an accelerometer to evaluate physical activity (PA) levels of various intensities (i.e. moderate PA (MPA), 3–5.9 metabolic equivalents (METs); VPA, ≥6 METs; moderate to vigorous PA (MVPA), ≥3 METs). Eight fitness items were assessed (grip strength, bent-leg sit-up, sit-and-reach, side step, 50?m sprint, standing long jump, handball throw, and distance running) as part of the Japanese standardised fitness test. A fitness composite score was calculated using Japanese fitness norms, and participants were categorised according to their score from category A (most fit) to category E (least fit), with participants in categories D and E defined as having low fitness. It was found that for boys, accumulating more than 80.7?min/day of MVPA may reduce the probability of low fitness (odds ratio (ORs) [95% confidence interval (CI)]?=?0.17 [0.06–0.47], p?=?.001). For girls, accumulating only 8.4?min of VPA could reduce the likelihood of exhibiting low fitness (ORs [95% CI]?=?0.23 [0.05–0.89], p?=?.032). These results reveal that there are sex-specific differences in the relationship between PA and physical fitness in adolescents, suggesting that sex-specific PA recommendation may be needed to improve physical fitness in adolescents.  相似文献   

如何开展家长培训     

Barbara T.Doyle  汤素梅 《现代特殊教育》2007,(7):78-78

残障儿童的父母．是孩子一生最好的教育者，因为他们在孩子成长的过程中无私奉献，恪尽责任。对那些有残障儿童的家庭而言．“知识就是力量”这句话就是真理。这些家长需要掌握关于残障症状的特点、教育治疗方案和策略等信息，以提升日常生活质量。家长们也想知道什么样的服务最适合孩子．如何获得这些服务．如何定位家长角色以确保孩子的进步．[第一段]  相似文献   

Examining the research base of the regular education initiative: efficacy studies and the adaptive learning environments model   总被引：1，自引：0，他引：1  

D P Hallahan  C E Keller  J D McKinney  J W Lloyd  T Bryan 《Journal of learning disabilities》1988,21(1):29-35, 55

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Developmental links of very early phonological and language skills to second grade reading outcomes: strong to accuracy but only minor to fluency     

Puolakanaho A  Ahonen T  Aro M  Eklund K  Leppänen PH  Poikkeus AM  Tolvanen A  Torppa M  Lyytinen H 《Journal of learning disabilities》2008,41(4):353-370

The authors examined second grade reading accuracy and fluency and their associations via letter knowledge to phonological and language predictors assessed at 3.5, 4.5, and 5.5 years in children in the Jyv?skyl? Longitudinal Study of Dyslexia. Structural equation modeling showed that a developmentally highly stable factor (early phonological and language processing [EPLP]) behind key dyslexia predictors (i.e., phonological awareness, short-term memory, rapid naming, vocabulary, and pseudoword repetition) could already be identified at 3.5 years. EPLP was significantly associated with reading and spelling accuracy and by age with letter knowledge. However, EPLP had only a minor link with reading fluency, which was additionally explained by early letter knowledge. The results show that reading accuracy is well predicted by early phonological and language skills. Variation in fluent reading skills is not well explained by early skills, suggesting factors other than phonological core skills. Future research is suggested to explore the factors behind the development of fast and accurate decoding skills.  相似文献   

Creativity in open and traditional classrooms     

C T Ramey  V Piper 《Child development》1974,45(2):557-560

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Communicating data to schools     

T. W. Maxwell 《The Australian Educational Researcher》1990,17(3):85-93

The article explores the communication of data to schools by researchers and evaluators. The stance is taken that the research process is one in which the participants are involved in a mutually supportive enterprise in which the relationship should be viewed as co-operation between professional colleagues, i.e., a relationship in which perceived status is minimised but one in which different knowledge and expertise exists on both sides. It is argued that the obtaining of data at school sites requires the researcher to provide data to their sources. Careful consideration needs to be given by researchers to the process and methods of communication of data to school communities. Issues addressed include audience, terminology, prose and other forms of presentation. A case is made for the researcher to become involved in dialogue to enhance the “meaning-making” of practitioners and themselves. The article concludes with a set of guidelines for researchers.  相似文献   

Assessment of Teacher Reactions to a Standards-Based Teacher Evaluation System: A Pilot Study*     

Anthony T. Milanowski  Herbert G. Heneman III 《Journal of Personnel Evaluation in Education》2001,15(3):193-212

This article reports on teachers' reactions to a pilot implementation of a new standards-based teacher evaluation system in a medium-sized Midwestern school district. The system, based on the Framework for Teaching (Danielson, 1996), was intended to serve as the foundation for a new knowledge and skill pay plan for teachers. Teacher reactions were measured using both interview and survey methods. Teachers' overall favorableness toward the system, as measured by the survey, was correlated with acceptance of the teaching standards, perception of the evaluation process as fair and the evaluator as capable and objective, and perception that the evaluation system had a positive impact on their teaching. In interviews, teachers perceived both positive and negative aspects of the system, and for many these more or less balanced each other. While most teachers accepted the evaluation standards and the need for an evaluation system, many also perceived that the system added too much to teachers' workloads and did not provide enough feedback. Based on these results several changes were made in the evaluation system prior to full implementation. The results are discussed with reference to previous research and the Personnel Evaluation Standards.  相似文献   

Bullying and the Unique Socioemotional Needs of Gifted and Talented Early Adolescents: Veteran Teacher Perspectives and Practices     

William T. Allen Jr. 《Roeper Review》2017,39(4):269-283

Much is written at the elementary school level concerning bullying and the socioemotional needs of gifted and talented (GT) students; however, in the last 10 years, little qualitative research exists concerning the early adolescent GT age group. In the social environment of classroom life, early and current research indicates that many of these students experience neurotic perfectionism, overexciteabilities (OEs), developmental asynchrony, and bullying. The formation of autonomous classes (GT-only classes) has afforded some hope concerning the amelioration of such problems; nevertheless, in this study, detailed evidence of classroom bullying in the form of social ostracism and teasing has been found with this GT age group. If left unchecked, psychological autopsies have shown these students suffering emotional difficulties and even committing suicide as a result of school and classroom torment. With such potential for classroom bullying problems, few studies address what veteran teachers of early adolescent GT students do to keep students psychologically safe. Within the social milieu of classroom life, and in comparison to research standards, this study explores three efficacious teacher perspectives and practices.  相似文献