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Jozo Grgic Bruno Lazinica Pavle Mikulic James W. Krieger Brad Jon Schoenfeld 《European Journal of Sport Science》2017,17(8):983-993
Although the effects of short versus long inter-set rest intervals in resistance training on measures of muscle hypertrophy have been investigated in several studies, the findings are equivocal and the practical implications remain unclear. In an attempt to provide clarity on the topic, we performed a systematic literature search of PubMed/MEDLINE, Scopus, Web of Science, Cochrane Library, and Physiotherapy Evidence Database (PEDro) electronic databases. Six studies were found to have met the inclusion criteria: (a) an experimental trial published in an English-language peer-reviewed journal; (b) the study compared the use of short (≤60?s) to long (>60?s) inter-set rest intervals in a traditional dynamic resistance exercise using both concentric and eccentric muscle actions, with the only difference in resistance training among groups being the inter-set rest interval duration; (c) at least one method of measuring changes in muscle mass was used in the study; (d) the study lasted for a minimum of four weeks, employed a training frequency of ≥2 resistance training days per week, and (e) used human participants without known chronic disease or injury. Current evidence indicates that both short and long inter-set rest intervals may be useful when training for achieving gains in muscle hypertrophy. Novel findings involving trained participants using measures sensitive to detect changes in muscle hypertrophy suggest a possible advantage for the use of long rest intervals to elicit hypertrophic effects. However, due to the paucity of studies with similar designs, further research is needed to provide a clear differentiation between these two approaches. 相似文献
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The significance of family influences for children’s development is beyond dispute. Social disparities in stimulation provided by families and their influence on cognitive competencies have frequently been pointed out. However, little notice has been attracted to the variety of everyday family activities and their importance for children’s behavioral and competence development. Focusing on 6 to 8 years old children (n?=?1,377), this paper investigates firstly which factors affect mothers’ education-oriented and outdoor activities with their child, children’s involvement in household chores and aspects of parenting. Secondly, we analyze how these different types of activities as well as the parenting climate relate to children’s problem behavior, prosocial behavior, and everyday language skills. Cross-sectional regression analyses point to advantages of high maternal education and child-centered parenting. High maternal educational resources facilitate a focus on education-oriented activities, while outdoor activities and children’s involvement in household chores stand back. In addition to child-centered parenting, features of everyday family activities prove relevant for children’s behavioral and competence development. 相似文献
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Purpose:We aimed to perform a systematic review and meta-analysis of the effects of training to muscle failure or non-failure on muscular strength and hypertrophy.Methods:Meta-analyses of effect sizes(ESs)explored the effects of training to failure vs.non-failure on strength and hypertrophy.Subgroup meta-analyses explored potential moderating effects of variables such as training status(trained vs.untrained),training volume(volume equated vs.volume non-equated),body region(upper vs.lower),exercise selection(multi-vs.single-joint exercises(only for strength)),and study design(independent vs.dependent groups).Results:Fifteen studies were included in the review.All studies included young adults as participants.Meta-analysis indicated no significant difference between the training conditions for muscular strength(ES=-0.09,95%confidence interval(95%CI):-0.22 to 0.05)and for hypertrophy(ES=0.22,95%CI:-0.11 to 0.55).Subgroup analyses that stratified the studies according to body region,exercise selection,or study design showed no significant differences between training conditions.In studies that did not equate training volume between the groups,the analysis showed significant favoring of non-failure training on strength gains(ES=-0.32,95%CI:-0.57 to-0.07).In the subgroup analysis for resistance-trained individuals,the analysis showed a significant effect of training to failure for muscle hypertrophy(ES=0.15,95%CI:0.03-0.26).Conclusion:Training to muscle failure does not seem to be required for gains in strength and muscle size.However,training in this manner does not seem to have detrimental effects on these adaptations,either.More studies should be conducted among older adults and highly trained individuals to improve the generalizability of these findings. 相似文献
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PurposeThis review aimed to synthesize previous findings on the test–retest reliability of the 30–15 Intermittent Fitness Test (IFT).MethodsThe literature searches were performed in 8 databases. Studies that examined the test–retest reliability of the 30–15 IFT and presented the intraclass correlation coefficient (ICC) and/or the coefficient of variation (CV) for maximal velocity and/or peak heart rate were included. The consensus-based standards for the selection of health measurement instruments (COSMIN) checklist was used for the assessment of the methodological quality of the included studies.ResultsSeven studies, with a total of 10 study groups, explored reliability of maximal velocity assessed by the 30–15 IFT. ICCs ranged from 0.80 to 0.99, where 70% of ICCs were ≥0.90. CVs for maximal velocity ranged from 1.5% to 6.0%. Six studies, with a total of 7 study groups, explored reliability of peak heart rate as assessed by the 30–15 IFT. ICCs ranged from 0.90 to 0.97 (i.e., all ICCs were ≥0.90). CVs ranged from 0.6% to 4.8%. All included studies were of excellent methodological quality.ConclusionFrom the results of this systematic review, it can be concluded that the 30–15 IFT has excellent test–retest reliability for both maximal velocity and peak heart rate. The test may, therefore, be used as a reliable measure of fitness in research and sports practice. 相似文献
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Jozo Grgic 《European Journal of Sport Science》2018,18(2):219-225
The positive effects of caffeine ingestion on aerobic performance are well-established; however, recent findings are suggesting that caffeine ingestion might also enhance components of anaerobic performance. A commonly used test of anaerobic performance and power output is the 30-second Wingate test. Several studies explored the effects of caffeine ingestion on Wingate performance, with equivocal findings. To elucidate this topic, this paper aims to determine the effects of caffeine ingestion on Wingate performance using meta-analytic statistical techniques. Following a search through PubMed/MEDLINE, Scopus, and SportDiscus®, 16 studies were found meeting the inclusion criteria (pooled number of participants?=?246). Random-effects meta-analysis of standardized mean differences (SMD) for peak power output and mean power output was performed. Study quality was assessed using the modified version of the PEDro checklist. Results of the meta-analysis indicated a significant difference (p?=?.005) between the placebo and caffeine trials on mean power output with SMD values of small magnitude (0.18; 95% confidence interval: 0.05, 0.31; +3%). The meta-analysis performed for peak power output indicated a significant difference (p?=?.006) between the placebo and caffeine trials (SMD?=?0.27; 95% confidence interval: 0.08, 0.47 [moderate magnitude]; +4%). The results from the PEDro checklist indicated that, in general, studies are of good and excellent methodological quality. This meta-analysis adds on to the current body of evidence showing that caffeine ingestion can also enhance components of anaerobic performance. The results presented herein may be helpful for developing more efficient evidence-based recommendations regarding caffeine supplementation. 相似文献
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The goal of this randomized, double-blind, cross-over study was to assess the acute effects of caffeine ingestion on muscular strength and power, muscular endurance, rate of perceived exertion (RPE), and pain perception (PP) in resistance-trained men. Seventeen volunteers (mean?±?SD: age?=?26?±?6 years, stature?=?182?±?9?cm, body mass?=?84?±?9?kg, resistance training experience?=?7?±?3 years) consumed placebo or 6?mg?kg?1 of anhydrous caffeine 1?h before testing. Muscular power was assessed with seated medicine ball throw and vertical jump exercises, muscular strength with one-repetition maximum (1RM) barbell back squat and bench press exercises, and muscular endurance with repetitions of back squat and bench press exercises (load corresponding to 60% of 1RM) to momentary muscular failure. RPE and PP were assessed immediately after the completion of the back squat and bench press exercises. Compared to placebo, caffeine intake enhanced 1RM back squat performance (+2.8%; effect size [ES]?=?0.19; p?=?.016), which was accompanied by a reduced RPE (+7%; ES?=?0.53; p?=?.037), and seated medicine ball throw performance (+4.3%, ES?=?0.32; p?=?.009). Improvements in 1RM bench press were not noted although there were significant (p?=?.029) decreases in PP related to this exercise when participants ingested caffeine. The results point to an acute benefit of caffeine intake in enhancing lower-body strength, likely due to a decrease in RPE; upper-, but not lower-body power; and no effects on muscular endurance, in resistance-trained men. Individuals competing in events in which strength and power are important performance-related factors may consider taking 6?mg?kg?1 of caffeine pre-training/competition for performance enhancement. 相似文献
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Training frequency is considered an important variable in the hypertrophic response to regimented resistance exercise. The purpose of this paper was to conduct a systematic review and meta-analysis of experimental studies designed to investigate the effects of weekly training frequency on hypertrophic adaptations. Following a systematic search of PubMed/MEDLINE, Scoups, and SPORTDiscus databases, a total of 25 studies were deemed to meet inclusion criteria. Results showed no significant difference between higher and lower frequency on a volume-equated basis. Moreover, no significant differences were seen between frequencies of training across all categories when taking into account direct measures of growth, in those considered resistance-trained, and when segmenting into training for the upper body and lower body. Meta-regression analysis of non-volume-equated studies showed a significant effect favoring higher frequencies, although the overall difference in magnitude of effect between frequencies of 1 and 3+ days per week was modest. In conclusion, there is strong evidence that resistance training frequency does not significantly or meaningfully impact muscle hypertrophy when volume is equated. Thus, for a given training volume, individuals can choose a weekly frequency per muscle groups based on personal preference. 相似文献
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Rüdiger Heim Svenja Konowalczyk Mariana Grgic Miriam Seyda Ulrike Burrmann Thomas Rauschenbach 《Zeitschrift für Erziehungswissenschaft》2016,19(4):783-805
While internet based surveys have gained importance in recent years, their use in adolescent related research is rare at best. The present paper offers an overview of advantages and disadvantages of online surveys and discusses their use in regard to the questioning of adolescents. In a comparison between two random samples of 13 to 17 year olds, we examine how differences between a telephone (N?= 1,784) and an online (N?= 1,652) survey materialize in regard to the coverage rate, discontinuation behavior, and item-non-response. The sampling is analyzed further with regard to sociodemographic differences. While there are no expected coverage problems for the adolescent target group, the results show that adolescents from educated families, as well as those with a migration background, took part more often in the online survey as opposed to the telephone survey. Also, a more intensive mobile use of the internet, as well as in part greater sports activity, is connected to a higher willingness to take part in the survey which suggests that the survey topic influences the willingness to participate. 相似文献
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Winterhalter-Jadrić M Causević A Jadrić R Corić J Hasić S Kiseljaković E 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2011,21(1):12-14
In this paper we would like to briefly introduce readers to the situation in the field of laboratory medicine in Bosnia and Herzegovina, with a focus on training in the field of medical biochemistry. As in some of neighboring countries, term Medical biochemist is the usual name for the Clinical biochemist or Clinical chemist in Bosnia and Herzegovina. Despite the difficult period through which the profession had passed in the last two decades, laboratory work, particularly clinical biochemistry, has managed to retain the necessary quality and keep pace with the developed world. In post war period, Society of Medical Biochemists of Bosnia and Herzegovina held regular meetings each year as a part of "life long learning" process, where both scientific and vocational lecturers presented their work. A single law on the state level would provide us with more defined and precise answers, such as: who can get a specialization, how long should last the training for medical biochemistry specialists (duration in years). This law should be in consent with the program described in EC4 or other documents given by the EFCC (European Federation of Clinical Chemistry and Laboratory Medicine) and IFCC (International Federation of Clinical Chemistry and Laboratory Medicine). 相似文献
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This article deals with playing a musical instrument as an important form of music related activities in the development and socialization of children and youth. The authors discuss aspects of arts education and reflect concepts of interest. They focus on the musical socialization and its contexts of today, so the question, which children and young persons are playing an instrument as well as a systematic analysis of places where adolescents are playing music. The self-organized and non-goal oriented learning processes in music activities are focused, reflecting theories of social inequalities. The results of the empirical findings show differences related to social class in playing an instrument and its choice, but not in places where music is done. Especially if adolescents play an instrument with corresponding interest, intensity, forms of activities and motifs of playing do not differ by social background. 相似文献
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