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Tom Geeson-Brown Ben Jones Kevin Till Sarah Chantler Kevin Deighton 《Journal of sports sciences》2020,38(19):2161-2176
ABSTRACT This systematic review and meta-analysis aimed to determine differences in body compositionn between playing standard and age in male rugby union and rugby league athletes. The MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines for design, implementation, and reporting were followed. Studies were required to be in male rugby union or league and have body composition as the primary or secondary outcome. Data was required to be presented separately for positional groups and body composition presented as whole-body. A systematic search was performed in PubMed, Cochrane Library, MEDLINE, SPORTDiscus, and CINHAHL via EBSCOhost. 57 studies were included for meta-analysis. Results highlighted significantly higher fat-free mass in senior elite than senior sub-elite or junior elite athletes for all RU and RL forwards. Small and non-significant differences were found in fat mass between rugby union playing standards and age categories. Rugby league senior elite forwards had less fat mass than junior elite forwards. Practitioners should prioritise training and nutritional strategies that maximise fat-free mass development, especially in junior elite cohorts. 相似文献
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Ford P De Ste Croix M Lloyd R Meyers R Moosavi M Oliver J Till K Williams C 《Journal of sports sciences》2011,29(4):389-402
Within the UK, the "Long Term Athlete Development" (LTAD) model has been proposed by a variety of national governing bodies to offer a first step to considering the approach to talent development. The model, which is primarily a physiological perspective, presents an advancement of understanding of developing athletic potential alongside biological growth. It focuses on training to optimize performance longitudinally, and considers sensitive developmental periods known as "windows of opportunity". However, it appears that there are a number of problems with this theoretical model that are not necessarily transparent to coaches. Principally, the model is only one-dimensional, there is a lack of empirical evidence upon which the model is based, and interpretations of the model are restricted because the data on which it is based rely on questionable assumptions and erroneous methodologies. Fundamentally, this is a generic model rather than an individualized plan for athletes. It is crucial that the LTAD model is seen as a "work in progress" and the challenge, particularly for paediatric exercise scientists, is to question, test, and revise the model. It is unlikely that this can be accomplished using classical experimental research methodology but this should not deter practitioners from acquiring valid and reliable evidence. 相似文献
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Monitoring of physical fitness (PF) in childhood is important from a societal as well as individual perspective to ensure and support healthy child development. Hence, the German Standing Conference of the Ministers of Education and Cultural Affairs together with the German Olympic Federation recommend the usage of motor tests, for instance in schools, to implement targeted interventions. Results of motor assessments are interpreted using reference categories to prevent overinterpretation of small but meaningless intra- and inter individual differences. Furthermore, temporal trends can influence the validity of these reference categories. The aims of the study are (1) to examine short- and medium-term changes in PF in middle childhood (2) to evaluate implications for reference values and the validity of the construct PF, (3) to provide valid reference values for eight- to nine-year-old children. In the school years 2011–2016, over 20,000 third-graders completed the German Motor Test (GMT) in the project “Berlin has Talent”. Possible temporal trends are examined using regressions and cross-tables. Implications of these changes on the construct PF are analyzed using Rasch measurement. Four out of seven tasks showed temporal changes. However, the validity and unidimensionality of the GMT are confirmed (p?>?0.90), if balancing backwards is excluded from the model. On the one hand, task-related changes of children’s motor performance within five years support the requirement of a comprehensive continuous monitoring to enable early interventions. On the other hand, they call for continuous evaluation of reference values of the GMT, which should rely on representative and sufficiently large samples. 相似文献
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Thomas Sawczuk Ben Jones Sean Scantlebury Kevin Till 《Journal of sports sciences》2018,36(21):2431-2437
This study assessed the influence of training load, exposure to match play and sleep duration on two daily wellbeing measures in youth athletes. Forty-eight youth athletes (age 17.3 ± 0.5 years) completed a daily wellbeing questionnaire (DWB), the Perceived Recovery Status scale (PRS), and provided details on the previous day’s training loads (TL) and self-reported sleep duration (sleep) every day for 13 weeks (n = 2727). Linear mixed models assessed the effect of TL, exposure to match play and sleep on DWB and PRS. An increase in TL had a most likely small effect on muscle soreness (d = ?0.43;± 0.10) and PRS (d = ?0.37;± 0.09). Match play had a likely small additive effect on muscle soreness (d = ?0.26;± 0.09) and PRS (d = ?0.25;± 0.08). An increase in sleep had a most likely moderate effect on sleep quality (d = 0.80;± 0.14); a most likely small effect on DWB (d = 0.45;± 0.09) and fatigue (d = 0.42;± 0.11); and a likely small effect on PRS (d = 0.25;± 0.09). All other effects were trivial or did not reach the pre-determined threshold for practical significance. The influence of sleep on multiple DWB subscales and the PRS suggests that practitioners should consider the recovery of an athlete alongside the training stress imposed when considering deviations in wellbeing measures. 相似文献
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Till Bruckermann Ellen Aschermann André Bresges Kirsten Schlüter 《International Journal of Science Education》2013,35(6):701-722
ABSTRACTPromoting preservice science teachers’ experimentation competency is required to provide a basis for meaningful learning through experiments in schools. However, preservice teachers show difficulties when experimenting. Previous research revealed that cognitive scaffolding promotes experimentation competency by structuring the learning process, while metacognitive and multimedia support enhance reflection. However, these support measures have not yet been tested in combination. Therefore, we decided to use cognitive scaffolding to support students’ experimental achievements and supplement it by metacognitive and multimedia scaffolds in the experimental groups. Our research question is to what extent supplementing cognitive support by metacognitive and multimedia scaffolding further promotes experimentation competency. The intervention has been applied in a two-factorial design to a two-month experimental course for 63 biology teacher students in their first bachelor year. Pre-post-test measured experimentation competency in a performance assessment. Preservice teachers worked in groups of four. Therefore, measurement took place at group level (N?=?16). Independent observers rated preservice teachers’ group performance qualitatively on a theory-based system of categories. Afterwards, experimentation competency levels led to quantitative frequency analysis. The results reveal differing gains in experimentation competency but contrary to our hypotheses. Implications of combining scaffolding measures on promoting experimentation competency are discussed. 相似文献
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Till Koopmann Yvonne Steggemann-Weinrich Jochen Baumeister 《Research quarterly for exercise and sport》2017,88(3):365-370
Purpose: In sports games, coaches often use tactic boards to present tactical instructions during time-outs (e.g., 20 s to 60 s in basketball). Instructions should be presented in a way that enables fast and errorless information processing for the players. The aim of this study was to test the effect of different orientations of visual tactical displays on observation time and execution performance. High affordances in visual-spatial transformation (e.g., mental rotation processes) might impede information processing and might decrease execution performance with regard to the instructed playing patterns. Method: In a within-subjects design with 1 factor, 10 novice students were instructed with visual tactical instructions of basketball playing patterns with different orientations either showing the playing pattern with low spatial disparity to the players’ on-court perspective (basket on top) or upside down (basket on bottom). Results: The self-chosen time for watching the pattern before execution was significantly shorter and spatial accuracy in pattern execution was significantly higher when the instructional perspective and the real perspective on the basketball court had a congruent orientation. Conclusion: The effects might be explained by interfering mental rotation processes that are necessary to transform the instructional perspective into the players’ actual perspective while standing on the court or imagining themselves standing on the court. According to these results, coaches should align their tactic boards to their players’ on-court viewing perspective. 相似文献
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ABSTRACTThe purpose was to identify classes of different developmental trajectories of BMI and testing them for differences in motor competence (MC) and cardiorespiratory fitness (CRF), in children and adolescents (4 to 13 years of age). This was a 5 years’ longitudinal study with six cohorts. One hundred and forty-seven children (69 girls) divided into six cohorts participated. At baseline, the youngest and the oldest cohorts had 4 and 11 years of age, respectively. Height and weight were assessed, and BMI was calculated. MC was assessed with KTK and TGMD-2, and CRF was assessed with one-mile run/walk. Developmental trajectories of BMI were identified using latent class linear-mixed modelling. Latent class membership was explained according to covariates of MC and CRF. Two meaningful classes were identified. Class 1 (78.92% of the participants) showed lower initial BMI and a lower slope compared to class 2 (21.08% of the participants) (all ps < 0.001). Class membership only predicted trajectories in motor coordination, with children in class 1 having a better development.In conclusion, this study identified two meaningful trajectories for children based on their BMI development across five time points. In line with previous research, children with slower increasing BMI showed better motor coordination improvements. 相似文献
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Jörg Schorer Irene Faber Till Koopmann Dirk Büsch Joseph Baker 《Journal of sports sciences》2020,38(19):2208-2214
ABSTRACT Despite the importance of technique and tactics for athlete performance, there has been surprisingly little research on the value of these skills in talent identification and development. This study investigated the relationship between coaches’ early notational analyses of female youth handball players and the long-term success of these athletes. Participants included sixty-eight female handball players involved in a talent selection camp in Germany when they were between 12 and 14 years of age (mean = 14.42, SD = 0.42). All subsequently ended up as non-, semi- or professional adult players. During the initial selection camp, participants were evaluated on a range of quantitative and qualitative measures of technical and tactical skill. Results indicated significant differences between the groups, but only for the number of actions taken, not for the quality of those actions. While this seems counterintuitive, it may reflect the likelihood that more skilled and/or talented players take more actions. Further work is necessary to explore the validity and implications of these findings. 相似文献