The effect of leg kick on sprint front crawl swimming

Abstract

The aim of this study was to examine the influence of leg kick on the pattern, the orientation and the propulsive forces produced by the hand, the efficiency of the arm stroke, the trunk inclination, the inter-arm coordination and the intra-cyclic horizontal velocity variation of the hip in sprint front crawl swimming. Nine female swimmers swam two maximal trials of 25 m front crawl, with and without leg kick. Four camcorders were used to record the underwater movements. Using the legs, the mean swimming velocity increased significantly. On the contrary, the velocity and the orientation of the hand, the magnitude and the direction of the propulsive forces, as well as the Froude efficiency of the arm stroke were not modified. The hip intra-cyclic horizontal velocity variation was also not changed, while the index of coordination decreased significantly. A significant decrease (13%) was also observed in the inclination of the trunk. Thus, the positive effect of leg kick on the swimming speed, besides the obvious direct generation of propulsive forces from the legs, could probably be attributed to the reduction of the body’s inclination, while the generation of the propulsive forces and the efficiency of the arm stroke seem not to be significantly affected.     

Teaching Explicitly and Reflecting on Elements of Nature of Science: a Discourse-Focused Professional Development Program with Four Fifth-Grade Teachers

The nature of science (NOS) has become a central goal of science education in many countries. This study refers to a developmental work research program, in which four fifth-grade elementary in-service teachers participated. It aimed to improve their understandings of NOS and their abilities to teach it effectively to their students. The 1-year-long, 2012–2013, program consisted of a series of activities to support teachers to develop their pedagogical content knowledge of NOS. In order to accomplish our goal, we enabled teacher-researchers to analyze their own discourse practices and to trace evidence of effective NOS teaching. Many studies indicate the importance of examining teachers’ discussions about science in the classroom, since it is teachers’ understanding of NOS reflected in these discussions that will have a vital impact on students’ learning. Our proposal is based on the assumption that reflecting on the ways people form meanings enables us to examine and seek alternative ways to communicate aspects of NOS during science lessons. The analysis of discourse data, which has been carried out with the teacher-researchers’ active participation, indicated that initially only a few aspects of NOS were implicitly incorporated in teacher-researchers’ instruction. As the program evolved, all teacher-researchers presented more informed views on targeted NOS aspects. On the whole, our discourse-focused professional development program with its participatory, explicit, and reflective character indicated the importance of involving teacher-researchers in analyzing their own talk. It is this involvement that results in obtaining a valuable awareness of aspects concerning pedagogical content knowledge of NOS teaching.     

Assessing the difference in learning gain between a mixed reality application and drawing screencasts in neuroanatomy

Augmented, mixed, and virtual reality applications and content have surged into the higher education arena, thereby allowing institutions to engage in research and development projects to better understand their efficacy within curricula. However, despite the increasing interest, there remains a lack of robust empirical evidence to justify the mainstream acceptance of this approach as an effective and efficient learning tool. In this study, the impact of a mixed reality application focused on long spinal cord sensory and motor pathways is explored in comparison to an existing resource already embedded within an active curriculum (e.g., anatomy drawing screencasts). To assess the changes in learner gain, a quasi-randomized control trial with a pre- and post-test methodology was used on a cohort of Year 2 medical students, with both the absolute and normalized gain calculated. Similar patterns of learner gain were observed between the two groups; only the multiple-choice questionnaires were shown to be answered significantly higher with the screencast group. This study adds important empirical data to the emerging field of immersive technologies and the specific impact on short-term knowledge gain for neuroanatomy teaching, specifically that of long sensory and motor pathways. Despite the limitations of the study, it provides important additional data to the field and intends to support colleagues across the education landscape in making evidence-informed decisions about the value of including such resources into their curricula.     

Moving Bodies to Moving Minds: A Study of the Use of Motion-Based Games in Special Education

From an embodied learning perspective, the active human body can alter the function of the brain and therefore, the cognitive process. In this work, children’s activity using motion-based technology is framed as an example of embodied learning. The present investigation focuses on the use of a series of Kinect-based educational games by 31 elementary students with special educational needs in mainstream schools, during a five-month intervention study. Results based on psychometric pre-post testing in conjunction with games-usage analytics, a student attitudinal scale, teachers’ reflection notes and teacher interviews, demonstrated the positive impact of the games on children’s short-term memory skills and emotional stage. Overall, the study improves our understanding of embodied learning via motion-based technology in teaching and learning with children with special educational needs.     

Associations between urbanization and the home language environment: Evidence from a LENA study in rural and peri-urban China

In low- and middle-income countries, urbanization has spurred the expansion of peri-urban communities, or urban communities of formerly rural residents with low socioeconomic status. The growth of these communities offers researchers an opportunity to measure the associations between the level of urbanization and the home language environment (HLE) among otherwise similar populations. Data were collected in 2019 using Language Environment Analysis observational assessment technology from 158 peri-urban and rural households with Han Chinese children (92 males, 66 females) aged 18–24 months in China. Peri-urban children scored lower than rural children in measures of the HLE and language development. In both samples, child age, gender, maternal employment, and sibling number were positively correlated with the HLE, which was in turn correlated with language development.     

Effect of 4 weeks of basic military training on peripheral blood leucocytes and urinary excretion of catecholamines and cortisol

In this study, we assessed the effects of a 4 week basic military physical training programme for male recruits of the Hellenic Air Force on the number and distribution of circulating immune cells and adrenergic and adrenocortical hormonal responses. One group of recruits (exercised, n = 48) participated in moderate intermittent physical exercise, whereas a second group (non-exercised controls, n = 9) performed only light work in the barracks. Both groups participated in the same non-physical, classroom-type training and testing. Military training by the exercised group resulted in significant increases in CD4+ T-lymphocytes, renal cortisol excretion and the urinary noradrenaline/adrenaline ratio, together with reductions in neutrophils and the neutrophil/lymphocyte ratio. In the exercised group, the urinary noradrenaline/adrenaline ratio correlated positively with the training-induced changes in CD4+ T-lymphocytes and negatively with changes in the neutrophil/lymphocyte ratio. No significant relationship was found between training-induced increases in cortisol excretion and any of the peripheral blood cell alterations. Our results indicate that 4 weeks of military training consisting of intermittent moderate exercise resulted in a significant increase in CD4+ T-lymphocytes and reduction in neutrophils. These changes were probably driven by alterations in hormonal status, including the significant impact of sympathetic nervous system activation.     

Student perceptions in the design of a computer card game for learning computer literacy issues: a case study

The aim of this work was twofold. First, an empirical study was designed aimed at investigating the perceptions that entry-level non-computing majors -namely Physical Education and Sport Science (PESS) undergraduate students- hold about basic Computer Literacy (CL) issues. The participants were 90 first-year PESS students, and their perceptions were elicited through a written questionnaire. The data analysis revealed scientifically acceptable perceptions as well as various empirical, vague, incomplete and erroneous perceptions. Second, those students’ prior knowledge was utilized to design and implement an Educational Computer Card Game (ECCG) aimed at helping PESS students overcome their conceptual difficulties and approach the aforementioned CL issues in a scientifically consistent manner. The ECCG was designed taking into account basic digital game-based learning principles in combination with basic aspects of social and constructivist perspectives to learning. The ECCG was also pilot-tested in the field with real students, and the results were encouraging.     

Physics instruction from epistemological and didactical bases

We present criteria for the analysis and elaboration of the content of instruction, at middle school level, in a specific domain: physics. This content, which we call the knowledge to be taught, has to respect several constraints in order to be teachable in a real school. Here we have chosen to analyse in depth those constraints which are related to the specific features of the physics. One of the constraints is a goal which, very often, justifies physics teaching: the operational aspect of physics knowledge in everyday life. The other constraint is related to a crucial aspect of an experimental science: the need for coherence between the formal aspects and their field of applicability. Our analysis is based on an epistemological approach to physics knowledge and on assumptions about learning. This analysis is related to the case of an innovative programme of teaching on electricity.This article was accepted during the editorship of Paul Lefrere.     

SECONDARY SCHOOL STUDENTS’ UNDERSTANDING OF MATHEMATICAL INDUCTION: STRUCTURAL CHARACTERISTICS AND THE PROCESS OF PROOF CONSTRUCTION

In this study, we investigate the meaning students attribute to the structure of mathematical induction (MI) and the process of proof construction using mathematical induction in the context of a geometric recursion problem. Two hundred and thirteen 17-year-old students of an upper secondary school in Greece participated in the study. Students’ responses in 3 written tasks and the interviews with 18 of them are analyzed. Though MI is treated operationally in school, the students, when challenged, started to recognize the structural characteristics of MI. In the case of proof construction, we identified 2 types of transition from argumentation to proof, interwoven in the structure of the geometrical pattern. In the first type, MI was applied to the algebraic statement that derived from the direct translation of the geometrical situation. In the second type, MI was embedded functionally in the geometrical structure of the pattern.     

FORUM: Giving oneself over to science – Exploring the roles of subjectivities and identities in learning science

In this piece, Elizabeth Moje discusses with the authors of FORUM: Giving oneself over to science: Exploring the roles of subjectivities and identities in learning science (Tucker-Raymond, Varelas, & Pappas) the challenges and potentials of theorizing about the role of identities in learning science. The authors debate how identities and subjectivities should be conceptualized, and whether learning science requires people to change identities and/or subjectivities. In particular, the authors discuss the potential for thinking about how identities are enacted in practices, and how teachers might construct practices that evoke the identities associated with science as a way of developing opportunities for deep science learning. Elizabeth Birr Moje is an Arthur F. Thurnau Professor of Literacy, Language, and Culture in Educational Studies, a Faculty Associate in the Institute for Social Research and a faculty affiliate with Latina/o Studies at the University of Michigan, Ann Arbor. Moje teaches undergraduate and graduate courses in secondary and adolescent literacy, cultural theory, and qualitative research methods. Her research interests revolve around the intersection between the literacies and texts youth are asked to learn in the disciplines and the literacies and texts they engage outsIDe of school. Moje also studies how youth construct cultures and enact IDentities via their literacy practices outsIDe of school. Eli Tucker-Raymond is a doctoral student in the Literacy, Language, and Culture program at the University of Illinois at Chicago. He sees his evolving status as a social scientist fraught with similarities and differences between himself and social scientists “out in the world.' He is working toward a designated researcher and teacher IDentity that includes a focus on critical media literacy, collaborative action research, and developing praxis-oriented, critically-conscious learning communities in urban K-8 school settings. One evolutionary, co-constructed step toward that IDentity are these publications, his first. Maria Varelas is Professor of Science Education at the University of Illinois at Chicago. Her research, teaching, and service are highly interrelated, focusing on classroom-based teaching and learning of science in urban settings with linguistically and socio-culturally diverse populations, collaborative teacher action research, discourse in science classrooms, integration of science and literacy, and science education reform in elementary school and college science classrooms. She currently co-leads with colleagues in Education, Natural Sciences, and Computer Science, three US NSF multi-year grants. Her research has appeared in a variety of journals and edited books. Christine C. Pappas is Professor of Language and Literacy at the University of Illinois at Chicago. Her teaching and research focus on classroom discourse, genre (especially informational and science ones), teacher inquiry, collaborative school-university action research (CSUAR), and the development of culturally responsive pedagogy. She is a co-author of the 4th edition of An Integrated Language Perspective in the Elementary School: An Action Approach, which emphasizes the use of language and literacy and other modes of meaning as tools for inquiry and learning across the curriculum. She has co-edited two volumes on a Spencer-sponsored CSUAR project, Working with Teacher Researchers in Urban Classrooms: Transforming Literacy Curriculum Genres and Teacher Inquiries in Literacy Teaching-Learning: Learning to Collaborate in Elementary Urban Classrooms, and her research has been published in book chapters and various journals.