Experiential knowledge of expert coaches can help identify informational constraints on performance of dynamic interceptive actions     

Daniel Greenwood  Keith Davids  Ian Renshaw 《Journal of sports sciences》2013,31(4):328-335

Abstract

Coordination of dynamic interceptive movements is predicated on cyclical relations between an individual’s actions and information sources from the performance environment. To identify dynamic informational constraints, which are interwoven with individual and task constraints, coaches’ experiential knowledge provides a complementary source to support empirical understanding of performance in sport. In this study, 15 expert coaches from 3 sports (track and field, gymnastics and cricket) participated in a semi-structured interview process to identify potential informational constraints which they perceived to regulate action during run-up performance. Expert coaches’ experiential knowledge revealed multiple information sources which may constrain performance adaptations in such locomotor pointing tasks. In addition to the locomotor pointing target, coaches’ knowledge highlighted two other key informational constraints: vertical reference points located near the locomotor pointing target and a check mark located prior to the locomotor pointing target. This study highlights opportunities for broadening the understanding of perception and action coupling processes, and the identified information sources warrant further empirical investigation as potential constraints on athletic performance. Integration of experiential knowledge of expert coaches with theoretically driven empirical knowledge represents a promising avenue to drive future applied science research and pedagogical practice.  相似文献   

Efficient dielectrophoretic cell enrichment using a dielectrophoresis-well based system     

Mohd Azhar Abdul Razak  Kai F. Hoettges  Henry O. Fatoyinbo  Fatima H. Labeed  Michael P. Hughes 《Biomicrofluidics》2013,7(6)

Whilst laboratory-on-chip cell separation systems using dielectrophoresis are increasingly reported in the literature, many systems are afflicted by factors which impede “real world” performance, chief among these being cell loss (in dead spaces, attached to glass and tubing surfaces, or sedimentation from flow), and designs with large channel height-to-width ratios (large channel widths, small channel heights) that make the systems difficult to interface with other microfluidic systems. In this paper, we present a scalable structure based on 3D wells with approximately unity height-to-width ratios (based on tubes with electrodes on the sides), which is capable of enriching yeast cell populations whilst ensuring that up to 94.3% of cells processed through the device can be collected in tubes beyond the output.  相似文献   

Footedness in world soccer: an analysis of France '98     

David P. Carey  Geoff Smith  Daniel T. Smith  John W. Shepherd  Jan Skriver  Leslie Ord 《Journal of sports sciences》2013,31(11):855-864

Most football players and coaches agree that players are capable of learning to use both feet with equal frequency and efficiency – that is, become 'two-footed'. There is also some consensus that two-footed play is associated with skill in individual players. If these assumptions are true, then the world's elite football players should be substantially less 'one-footed' than the rest of the population. To examine this issue, we quantified the pattern of foot use in a sample of 236 players from 16 teams in the 1998 World Cup (France '98). Our findings indicate that World Cup players are as right-footed as the general population (~79%). The remaining players were largely leftfooted and as biased towards the use of their preferred foot as their right-footed counterparts. Very few players used each foot with equal frequency. Remarkably, both left- and right-footed players were as skilled, on average, with their non-preferred foot as they were with their preferred foot, on the rare occasions when they used it. Therefore, it is unlikely that infrequent use of one foot compared to the other foot can be accounted for by skill differences between the feet. Players were most asymmetrical for set pieces; nevertheless, first touches, passes, dribbles and tackles were rarely performed with the non-preferred foot as well. Our results support a biological model of foot preference and performance, as well as demonstrating the usefulness of soccer for studies of lateral asymmetries.  相似文献   

The effect of foot orthoses and insoles on running economy and performance in distance runners: A systematic review and meta-analysis     

Daniel Crago  Christopher Bishop 《Journal of sports sciences》2013,31(22):2613-2624

ABSTRACT

Foot orthoses and insoles are prescribed to runners, however their impact on running economy and performance is uncertain. The aim of this systematic review and meta-analysis was to determine the effect of foot orthoses and insoles on running economy and performance in distance runners. Seven electronic databases were searched from inception until June 2018. Eligible studies investigated the effect of foot orthoses or insoles on running economy (using indirect calorimetry) or running performance. Standardised mean differences (SMDs) were computed and meta-analyses were conducted using random effects models. Methodological quality was assessed using the Quality Index. Nine studies met the criteria and were included: five studies investigated the effect of foot orthoses on running economy and four investigated insoles. Foot orthoses were associated with small negative effects on running economy compared to no orthoses (SMD 0.42 [95% CI 0.17,0.72] p = 0.007). Shock absorbing insoles were also associated with negative effects on running economy, but an imprecise estimate (SMD 0.26 [95% CI ?0.33,0.84] p = 0.83). Quality Index scores ranged from 4 to 15 out of 17. Foot orthoses and shock absorbing insoles may adversely affect running economy in distance runners. Future research should consider their potential effects on running performance.  相似文献   

Where to go: Computational and visual what-if analyses in soccer     

Manuel Stein  Daniel Seebacher  Rui Marcelino  Tobias Schreck  Michael Grossniklaus  Daniel A. Keim 《Journal of sports sciences》2013,31(24):2774-2782

ABSTRACT

To prepare their teams for upcoming matches, analysts in professional soccer watch and manually annotate up to three matches a day. When annotating matches, domain experts try to identify and improve suboptimal movements based on intuition and professional experience. The high amount of matches needing to be analysed manually result in a tedious and time-consuming process, and results may be subjective. We propose an automatic approach for the realisation of effective region-based what-if analyses in soccer. Our system covers the automatic detection of region-based faulty movement behaviour, as well as the automatic suggestion of possible improved alternative movements. As we show, our approach effectively supports analysts and coaches investigating matches by speeding up previously time-consuming work. We enable domain experts to include their domain knowledge in the analysis process by allowing to interactively adjust suggested improved movement, as well as its implications on region control. We demonstrate the usefulness of our proposed approach via an expert study with three invited domain experts, one being head coach from the first Austrian soccer league. As our results show that experts most often agree with the suggested player movement (83%), our proposed approach enhances the analytical capabilities in soccer and supports a more efficient analysis.  相似文献   

Age differences in online processing of video: an eye movement study     

Kirkorian HL  Anderson DR  Keen R 《Child development》2012,83(2):497-507

Eye movements were recorded while sixty-two 1-year-olds, 4-year-olds, and adults watched television. Of interest was the extent to which viewers looked at the same place at the same time as their peers because high similarity across viewers suggests systematic viewing driven by comprehension processes. Similarity of gaze location increased with age. This was particularly true immediately following a cut to a new scene, partly because older viewers (but not infants) tended to fixate the center of the screen following a cut. Conversely, infants appear to require several seconds to orient to a new scene. Results are interpreted in the context of developing attention skills. Findings have implications for the extent to which infants comprehend and learn from commercial video.  相似文献   

Parenting and Child DRD4 Genotype Interact to Predict Children’s Early Emerging Effortful Control     

Heather J. Smith  Haroon I. Sheikh  Margaret W. Dyson  Thomas M. Olino  Rebecca S. Laptook  C. Emily Durbin  Elizabeth P. Hayden  Shiva M. Singh  Daniel N. Klein 《Child development》2012,83(6):1932-1944

Effortful control (EC), or the trait‐like capacity to regulate dominant responses, has important implications for children’s development. Although genetic factors and parenting likely influence EC, few studies have examined whether they interact to predict its development. This study examined whether the DRD4 exon III variable number tandem repeat polymorphism moderated the relation between parenting and children’s EC. Three hundred and eighty‐two 3‐year‐olds and primary caregivers completed behavioral tasks assessing children’s EC and parenting. Children’s DRD4 genotypes moderated the relation between parenting and EC: Children with at least one 7‐repeat allele displayed lower EC in the context of negative parenting than children without this allele. These findings suggest opportunities for modifying early risk for low EC.  相似文献   

A longitudinal examination of childhood maltreatment and adolescent obesity: results from the National Longitudinal Study of Adolescent Health (AddHealth) Study     

Shin SH  Miller DP 《Child abuse & neglect》2012,36(2):84-94

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Effective action research: Developing reflective thinking and practice (2nd edn)     

Jonathan Hughes 《British Educational Research Journal》2012,38(4):697-699

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The debate on learning assessments in developing countries     

Daniel A. Wagner  Marlaine Lockheed  Ina Mullis  Michael O. Martin  Anil Kanjee  Amber Gove 《Compare》2012,42(3):509-545

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