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The relationship between peak height velocity and physical performance in youth soccer players 总被引：1，自引：1，他引：0
Philippaerts RM Vaeyens R Janssens M Van Renterghem B Matthys D Craen R Bourgois J Vrijens J Beunen G Malina RM 《Journal of sports sciences》2006,24(3):221-230
Longitudinal changes in height, weight and physical performance were studied in 33 Flemish male youth soccer players from the Ghent Youth Soccer Project. The players' ages at the start of the study ranged from 10.4 to 13.7 years, with a mean age of 12.2 +/- 0.7 years. Longitudinal changes were studied over a 5 year period. Peak height velocity and peak weight velocity were determined using non-smoothed polynomials. The estimations of peak height velocity, peak weight velocity and age at peak height velocity were 9.7 +/- 1.5 cm x year-1, 8.4 +/- 3.0 kg x year-1 and 13.8 +/- 0.8 years, respectively. Peak weight velocity occurred, on average, at the same age as peak height velocity. Balance, speed of limb movement, trunk strength, upper-body muscular endurance, explosive strength, running speed and agility, cardiorespiratory endurance and anaerobic capacity showed peak development at peak height velocity. A plateau in the velocity curves was observed after peak height velocity for upper-body muscular endurance, explosive strength and running speed. Flexibility exhibited peak development during the tear after peak height velocity. Trainers and coaches should be aware of the individual characteristics of the adolescent growth spurt and the training load should also be individualized at this time. 相似文献
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Machado-Rodrigues AM Coelho-E-Silva MJ Mota J Cyrino E Cumming SP Riddoch C Beunen G Malina RM 《Journal of sports sciences》2011,29(14):1503-1514
The agreement between self-reported and objective estimates of activity energy expenditure was evaluated in adolescents by age, sex, and weight status. Altogether, 403 participants (217 females, 186 males) aged 13-16 years completed a 3-day physical activity diary and wore a GT1M accelerometer on the same days. Partial correlations (controlling for body mass) were used to determine associations between estimated activity energy expenditure (kcal · min(-1)) from the diary and accelerometry. Differences in the magnitude of the correlations were examined using Fisher's r to z transformations. Bland-Altman procedures were used to determine concordance between the self-reported and objective estimates. Partial correlations between assessments of activity energy expenditure (kcal · min(-1)) did not differ significantly by age (13-14 years: r = 0.41; 15-16 years: r = 0.42) or weight status (normal weight: r = 0.42; overweight: r = 0.39). The magnitude of the association was significantly affected by sex (Δr = 0.11; P < 0.05). The agreement was significantly higher in males than in females. The relationship between activity energy expenditure assessed by the objective method and the 3-day diary was moderate (controlling for weight, correlations ranged between 0.33 and 0.44). However, the 3-day diary revealed less agreement in specific group analyses; it markedly underestimated activity energy expenditure in overweight/obese and older adolescents. The assessment of activity energy expenditure is complex and may require a combination of methods. 相似文献
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David H. Guston 《Minerva》1994,32(1):25-52
Conclusion The Allison Commission focused attention on the administration of the scientific bureaux and its relation to the jurisdictional system in the Congress. The commission also had a more considerable influence on congressional policy towards the scientific bureaux than was previously thought. Legislative recommendations offered by the Allison Commission became law, even if they avoided the notice of congressional opponents through the strategic manipulation of the appropriations process. Hilary Herbert was not a crude enemy of science, but a staunch defender of the obligations of Congress to scrutinise the expenditure of funds it allocated.This detailed political history of the Allison Commission is a necessary part of any history of American science policy. William Boyd Allison and Hilary Herbert were, no less than scientists like Powell, initiators of a tradition which has continued to be important in American governmental science policy.The form of the special committee devoted to scientific issues was initiated by the Allison Commission. It prefigured more recent and familiar congressional inquiries like the Joint Committee on Atomic Energy, the Government Operations Committee under Representative Fountain, the House Science Policy Task Force, and the Energy and Commerce Committee under Representative Dingell. The attentiveness to details like pay, printing, food and morale—as small but manageable parts of the larger enterprise—foreshadows more contemporary inquiries into the details of the procedures for awarding grants and contracts and the assurances of financial and scientific integrity. The mechanisms of control applied to governmental science by the Allison Commission—particularly itemised appropriations, but also control over personnel through promotions and control of bureaucratic organisation by virtue of congressional rather than disciplinary organisation—stand as early examples of how Congress may continue to exert its constitutional authority to scrutinise an innovative and entrepreneurial scientific community. 相似文献
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Simonete Pereira Da Silva Gaston Beunen António Prista José Maia 《Journal of sports sciences》2013,31(1):104-113
Abstract The main purpose of this study was to track the performance and health-related physical fitness of girls from Brazil's Cariri region. In the “Healthy Growth in Cariri Study”, 294 girls from public and private schools were divided into four age cohorts – 8, 10, 12, and 14 years – and followed for three consecutive years, with an assessment every 6 months. Shuttle run, hand grip, standing long jump, trunk lift, curl-up, 12-min run, and fatness were used to rate physical fitness performance and health-related components on each of six occasions. Tracking was done in a stepwise manner, using auto-correlation, by modelling the individual history of change in performance of each girl, and using Foulkes and Davies’ γ-coefficient. SPSS 18.0 and TIMEPATH were used for data analysis. Auto-correlations evidenced low-to-moderate values in almost all components of performance and health-related physical fitness. Intra-individual tracking analysis showed large variation in all fitness components as a result of a wide spread in individual history of change in fitness performance. Population estimates of γ were low in all tests. Our results show low-to-moderate tracking of physical fitness components of girls. A wide range of intra-individual and inter-variability in fitness development was observed. 相似文献
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Lynn Matton Gaston Beunen Nathalie Duvigneaud Katrien Wijndaele Renaat Philippaerts Albrecht Claessens 《Journal of sports sciences》2013,31(9):1011-1024
Abstract Longitudinal studies provide unique opportunities but are also faced with several limitations. The purpose of this study was to document three of these issues (“imperfect” design, evolution of data collection methods, representativeness) by means of the Leuven Longitudinal Study on Lifestyle, Fitness and Health (LLSLFH). The LLSLFH (1969 – 2004) comprises observations on males between 12 and 18 years and at 30, 35, 40, and 47 years, and on females at 16 and 40 years. In the most recent phase of the study, spouses and offspring were also included. The different phases and evolving research questions throughout the LLSLFH required an appropriate adaptation of the research design. The associated evolution of data collection methods largely reflects the changing ideas about physical fitness, body composition, and physical activity, the continuing search for new and better measurement techniques, and the need for adaptations with age. Ongoing study participants are representative in terms of body composition and, except for adolescence in males, also physical activity. No straightforward answer can be given concerning physical fitness. In both sexes, socio-economic status is above average. When informed about the possible “pitfalls” of longitudinal research in advance, several measures could be taken to prevent or limit them as much as possible. 相似文献
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David H. Guston 《Minerva》2012,50(3):363-379
Imagine putting together a jigsaw puzzle that works like the board game in the movie “Jumanji”: When you finish, whatever the puzzle portrays becomes real. The children playing “Jumanji” learn to prepare for the reality that emerges from the next throw of the dice. But how would this work for the puzzle of scientific research? How do you prepare for unlocking the secrets of the atom, or assembling from the bottom-up nanotechnologies with unforeseen properties – especially when completion of such puzzles lies decades after the first scattered pieces are tentatively assembled? In the inaugural issue of this journal, Michael Polanyi argued that because the progress of science is unpredictable, society must only move forward with solving the puzzle until the picture completes itself. Decades earlier, Frederick Soddy argued that once the potential for danger reveals itself, one must reorient the whole of one’s work to avoid it. While both scientists stake out extreme positions, Soddy’s approach – together with the action taken by the like-minded Leo Szilard – provides a foundation for the anticipatory governance of emerging technologies. This paper narrates the intertwining stories of Polanyi, Soddy and Szilard, revealing how anticipation influenced governance in the case of atomic weapons and how Polanyi’s claim in “The Republic of Science” of an unpredictable and hence ungovernable science is faulty on multiple levels. 相似文献
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Beunen GP Malina RM Freitas DL Thomis MA Maia JA Claessens AL Gouveia ER Maes HH Lefevre J 《Journal of sports sciences》2011,29(15):1683-1691
The purpose of this study was to validate and cross-validate the Beunen-Malina-Freitas method for non-invasive prediction of adult height in girls. A sample of 420 girls aged 10-15 years from the Madeira Growth Study were measured at yearly intervals and then 8 years later. Anthropometric dimensions (lengths, breadths, circumferences, and skinfolds) were measured; skeletal age was assessed using the Tanner-Whitehouse 3 method and menarcheal status (present or absent) was recorded. Adult height was measured and predicted using stepwise, forward, and maximum R (2) regression techniques. Multiple correlations, mean differences, standard errors of prediction, and error boundaries were calculated. A sample of the Leuven Longitudinal Twin Study was used to cross-validate the regressions. Age-specific coefficients of determination (R (2)) between predicted and measured adult height varied between 0.57 and 0.96, while standard errors of prediction varied between 1.1 and 3.9 cm. The cross-validation confirmed the validity of the Beunen-Malina-Freitas method in girls aged 12-15 years, but at lower ages the cross-validation was less consistent. We conclude that the Beunen-Malina-Freitas method is valid for the prediction of adult height in girls aged 12-15 years. It is applicable to European populations or populations of European ancestry. 相似文献