Effect of target change during the simple attack in fencing     

Marcos Gutiérrez-Dávila  Matteo Caletti  Raquel Antonio  Enrique Navarro 《Journal of sports sciences》2013,31(10):1100-1107

Abstract

The aim of this study was to test the effect that changing targets during a simple long lunge attack in fencing exerts on the temporal parameters of the reaction response, the execution speed, and the precision and the coordination of the movement pattern. Thirty fencers with more than 10 years of experience participated in this study. Two force platforms were used to record the horizontal components of the reaction forces and thereby to determine the beginning of the movement. A three-dimensional (3D) system recorded the spatial positions of the 9 markers situated on the fencer plus the epee, while a moving target was projected on a screen, enabling the control of the target change. The results indicated that when a target change is provoked the reaction time (RT), movement time (MT), and the time used in the acceleration phase of the centre of mass (CM) increases significantly with respect to the attack executed with a straight thrust. The speed and horizontal distance reached by the CM at the end of the acceleration phase (V_X(CM) and S_X(CM), respectively) significantly decreased, while the errors increased. However, the temporal sequence of the movement pattern did not appreciably change.  相似文献   

Physiological and biomechanical responses to walking underwater on a non-motorised treadmill: effects of different exercise intensities and depths in middle-aged healthy women     

Piero Benelli  Franca Colasanti  Massimiliano Ditroilo  Antonio Cuesta-Vargas  Giorgio Gatta  Francesco Giacomini 《Journal of sports sciences》2013,31(3):268-277

Abstract

Non-motorised underwater treadmills are commonly used in fitness activities. However, no studies have examined physiological and biomechanical responses of walking on non-motorised treadmills at different intensities and depths. Fifteen middle-aged healthy women underwent two underwater walking tests at two different depths, immersed either up to the xiphoid process (deep water) or the iliac crest (shallow water), at 100, 110, 120, 130 step-per-minute (spm). Oxygen consumption (VO₂), heart rate (HR), blood lactate concentration, perceived exertion and step length were determined. Compared to deep water, walking in shallow water exhibited, at all intensities, significantly higher VO₂ (+13.5%, on average) and HR (+8.1%, on average) responses. Water depth did not influence lactate concentration, whereas perceived exertion was higher in shallow compared to deep water, solely at 120 (+40%) and 130 (+39.4%) spm. Average step length was reduced as the intensity increased (from 100 to 130 spm), irrespective of water depth. Expressed as a percentage of maximum, average VO₂ and HR were: 64–76% of peak VO₂ and 71–90% of maximum HR, respectively at both water depths. Accordingly, this form of exercise can be included in the “vigorous” range of exercise intensity, at any of the step frequencies used in this study.  相似文献   

Variable training: effects on velocity and accuracy in the tennis serve     

Hector Hernández-Davo  Tomás Urbán  Jose Manuel Sarabia  Casto Juan-Recio  Francisco Javier Moreno 《Journal of sports sciences》2013,31(14):1383-1388

Abstract

Variable practice has been shown to be an effective strategy to improve open motor skills. However, the usefulness of this procedure in closed motor skills remains controversial. The following study has the objective of analysing the effects of variability practice in the improvement of a closed skill. The skill studied has been the tennis serve. Thirty young tennis players (13 ± 1.52 years), divided in two groups, took part in this study. One group practiced in variable conditions and the other group in consistency conditions. Both groups performed 12 training sessions (60 serves/session). The variable practice group improved their accuracy significantly compared with the consistency group (F_3.25 = 3.078; P = 0.035). The velocity of serve increased after training in both groups (F_3.25 = 15.890; P = 0.001). The practice in variable conditions seems to be effective in improving the performance of the tennis serve.  相似文献   

Providing metrics and automatic enhancement for hierarchical taxonomies     

Ghassan Beydoun  Francisco García-Sánchez  Cristin M. Vincent-Torres  Antonio A. Lopez-Lorca  Rodrigo Martínez-Béjar 《Information processing & management》2013

Taxonomies enable organising information in a human–machine understandable form, but constructing them for reuse and maintainability remains difficult. The paper presents a formal underpinning to provide quality metrics for a taxonomy under development. It proposes a methodology for semi-automatic building of maintainable taxonomies and outlines key features of the knowledge engineering context where the metrics and methodology are most suitable. The strength of the approach presented is that it is applied during the actual construction of the taxonomy. Users provide terms to describe different domain elements, as well as their attributes, and methodology uses metrics to assess the quality of this input. Changes according to given quality constraints are then proposed during the actual development of the taxonomy.  相似文献   

‘Governmentality’ in the origins of European female PE and sport: the Spanish case study (1883–1936)     

Raúl Sánchez García  Antonio Rivero Herraiz 《Sport, Education and Society》2013,18(4):494-510

The purpose of the paper is twofold: (1) to contribute to the analysis of the origins of modern European female PE and sports from a power perspective, inspired by Foucault's work; and (2) to present a detailed analysis of female PE and sport in Spain (1883–1936) as a specific European case study. It is argued that these physical activities could be conceived in the Spanish case as part of a specific kind of ‘governmentality’ with a dual nature. On the one hand they represented disciplinary ‘technologies of power’ over the female body. Selected physical activities—dictated mainly from the hygienic-moral position of the Regeneracionistas (‘Regenerationists’)—were exerted as a kind of ‘bio-power’ for the control of the female population. On the other hand, such kind of activities (especially sports) represented certain ‘technologies of the self’ for middle and upper class women. Through participation in sports, women gained a more active and public role in the Spanish society of the era, obtaining some degree of autonomy in self-governance over their bodies and their lives.  相似文献   

Effects of mat characteristics on plantar pressure patterns and perceived mat properties during landing in gymnastics     

Pedro Pérez-Soriano  Salvador Llana-Belloch  Gaspar Morey-Klapsing  Jose Antonio Perez-Turpin  Juan Manuel Cortell-Tormo 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(4):245-257

Shock absorption and stability during landings is provided by both, gymnast ability and mat properties. The aims of this study were to determine the influence of different mat constructions on their energy absorption and stability capabilities, and to analyse how these properties affect gymnast's plantar pressures as well as subjective mat perception during landing. Six mats were tested using a standard mechanical drop test. In addition, plantar pressures and subjective perception during landing were obtained from 15 expert gymnasts. The different mats influenced plantar pressures and gymnasts' subjective perception during landing of gymnasts. Significant correlations between plantar pressures at the medial metatarsal and lateral metatarsal zones of the gymnasts' feet with the different shock absorption characteristics of the mats were found. However, subjective perception tests were not able to discriminate mat functionality between the six mats as no significant correlations between the mechanical mat properties with the subjective perception of these properties were found. This study demonstrated that plantar pressures are a useful tool for discriminating different landing mats. Using similar approaches, ideally including kinematics as well, could help us in our understanding about the influences of different mats upon gymnast-mat interaction.  相似文献   

The interdependence of language and translational math skills among bilingual hispanic engineering students     

Jose P. Mestre  William J. Gerace  Jack Lochhead 《科学教学研究杂志》1982,19(5):399-410

The performance of 43 Hispanic engineering and science majors on a task that consists of reading a sentence describing a mathematical relationship between two variables, and then writing an equation describing the relationship, is investigated in both English and Spanish. Results are compared with grade point average and with language proficiency. Comparison of the bilingual group to a monolingual group consisting of 52 engineering and science students shows that performance, as measured by either the mathematical translation task or grade point average, is more strongly correlated with language proficiency for the bilingual group. Clinical interviews conducted with samples from each group reveal large differences in the interpretation of the mathematical task between Hispanics and monolinguals. Suggestions are made for the improvement of the technical education of Hispanics.  相似文献   

Teaching Modern Chemistry through ‘Recurrent Historical Teaching Models’     

José Antonio Chamizo 《Science & Education》2007,16(2):197-216

Today there are little more of 3 million chemist all over the world producing about 800,000 papers a year. They produce new substances – from some hundreds in 1800 to about 20 million now – the vast majority artificial. This rate is growing quite fast. Once the majority of chemistry teachers all over the world used textbooks as the main (sometimes the only) source of information, we became, without wanting to... history teachers! If ‘scientific literacy’ is the aim of science lessons in school, it is much more than the literacy now developed in science classrooms. It must include an understanding of the nature and process by which scientific activities are carried out. Recognition of the exponentially chemistry knowledge growth and the incompleteness of the current chemistry textbooks are thus intimately related to recognition of the need for recurrent historical teaching models.  相似文献   

The Evolution of the Concept of Capacitance Throughout the Development of the Electric Theory and the Understanding of Its Meaning by University Students     

Jenaro Guisasola  Jose L. Zubimendi  Jose M. Almudí  Mikel Ceberio 《Science & Education》2002,11(3):247-261

There are few didactic studies concerning the difficulties met by students inunderstanding the meaning of capacitance in a charged body. However, theunderstanding of capacitance can be a good indicator of the Students' learningof electrostatic theory in general. To describe Students' difficulties in learningthis concept we have considered, on the one hand, that individuals constructmental representations in order to help their understanding of the way a physicalsystem works under varied circumstances. On the other hand, a critical study ofthe history and epistemology of science is likely to enlighten us teachers andresearchers about the presence of qualitative leaps in the evolution of a concept.Thus, the consideration by teachers of these `discontinuities between meaningsfor the same concept, may lead them to understand Students' difficulties on learningit. We developed a historical study of the development of the capacitance conceptand an empirical study with students to identify historical and learning difficulties.The results obtained seem to show that most of the students who reason aboutaspects related to the charge of bodies and capacitance feel more comfortablewhen they talk in terms of charge than in terms of electric potential in a similarway to the first explanations of the early electric theories.  相似文献   

Primary pre-service teachers’ skills in planning a guided scientific inquiry     

Antonio García-Carmona  Ana M. Criado  Marta Cruz-Guzmán 《Research in Science Education》2017,47(5):989-1010

  相似文献