Biomechanical jumping differences among elite female handball players with and without previous anterior cruciate ligament reconstruction: a novel inertial sensor unit study

Persistent biomechanical and jumping capacity alterations have been observed among female athletes who have sustained anterior cruciate ligament (ACL) injuries. The purpose of this study was to examine if biomechanical jumping differences persist among a cohort of elite female handball players with previous ACL reconstruction several years after return to top-level competition. In order to achieve this goal, a direct mechanics simplified analysis by using a single Inertial Sensor Unit (IU) was used. Twenty-one elite female (6 anterior cruciate ligament reconstructed and 15 uninjured control players) handball players were recruited and evaluated 6.0 ± 3.5 years after surgical anterior cruciate ligament reconstruction. Bilateral and unilateral vertical jumps were performed to evaluate the functional performance and a single inertial sensor unit was employed in order to collect 3D acceleration and 3D orientation data. Previously ACL-reconstructed analysed athletes demonstrated significant (p < 0.05) alterations in relation to the three-dimensional axis (X–Y–Z) supported accelerations and differing jump phase durations, including jumping performance values, in both bilateral and unilateral jumping manoeuvres several years after ACL reconstruction. Identification of the encountered deficits through the use of an IU devise could provide clinicians with a new reliable tool for movement analysis in a clinical setting.     

Facilitating knowledge construction by customized supportive services

This research is aimed to assist individual learners to construct knowledge in online learning through providing them with customized supportive services. The services go beyond simply presenting course materials, but supply a diverse range of technological facilities, tools and services to assist individual learners to progress in the learning process. In this paper, the theoretical background for facilitating construction of knowledge by individual learners is built at the first, through the review of constructivist theories for learning and the objectivist ones. Then, a general conceptual model to describe any number of practices in learning and teaching online is built. It will be used to customize online learning environments to cater for various different learning demands. The services to support the individual’s knowledge construction are identified based on the relevant theoretical background. After that, software agents are proposed to customize the supportive services for individual learners based on their particular learning characteristics. Next, the implementation of these services is investigated and a system prototype is reported. Finally the preliminary research result and the further work are presented.     

‘Trust me,I do not know what I am talking about!’: The voice of the teacher beyond the oath and blasphemy

Educational theorists ranging from Ivan Illich to Jan Masschelein and Maarten Simons have described institutionalized schooling as a modernized, secular church, full of rituals, sacraments, and various incantations. For them, the function of the teacher as priest and schooling as baptism is highly problematic, separating education from the common world. As such, the educational theology of the school needs to be suspended in order for educational life to take on new meaning beyond the sacraments of learning. To further this line of inquiry, we turn to the work of Giorgio Agamben on the oath and its originary function of guaranteeing the truthfulness of language (‘sacrament of language’). Insofar as the oath is also operable in learning (in the voice of the teacher), we argue that such operability can be suspended through a dialogic practice called ‘community of infancy’, thereby making possible new, profane forms of educational life beyond baptism.     

UNIVERSITY‐LEVEL GENERAL ENVIRONMENTAL EDUCATION

The author describes the development of environmental education at Kharkov University in the USSR. The uniqueness of the main programme in general ecodevelopmental education is that its basic disciplinary affiliation is geography, a deliberate choice made by the university authorities’ which the author amply justifies. In the process of explaining this choice, he presents eight theses with regard to the social demand for ecologists and the ecologization of education and what he believes to be the three principal bases for general environmental education at the university level.     

Minding mathematicians’ discourses in investigations of their feedback on students’ proofs: a case study

Educational Studies in Mathematics - This article presents a research apparatus for investigating and making sense of stories that emerge from feedback that mathematicians provide on...     

Algorithm for adaptively smoothing the log-periodogram

We use the principle of minimum cross entropy (MCE) to build a non-parametric adaptive algorithm for smoothing the log-transformed periodogram, and construct an optimal estimate for the spectral density function of a process. We show that this estimate minimizes the cross-entropy with the log-transformed spectral density function of the process. The method is non-parametric and performs very well for the case of processes having rapidly changing spectra that exhibits a variable order of smoothness. The algorithm is locally based on linearly approximating the information present in the process, and uses this approximation to allow the bandwidth of the spectral window in the smoothed log-periodogram to vary. We extend the algorithm empirically for better application to processes having mixed, narrow-band spectra. Comparisons with other currently used procedures are performed through the means of simulated examples.     

Urine specific gravity as an indicator of dehydration in Olympic combat sport athletes; considerations for research and practice

Urine specific gravity (U_SG) is the most commonly reported biochemical marker used in research and applied settings to detect fluid deficits in athletes, including those participating in combat sports. Despite the popularity of its use, there has been a growing debate regarding the diagnostic accuracy and the applicability of U_SG in characterizing whole-body fluid status and fluctuations. Moreover, recent investigations report universally high prevalence of hypohydration (～90%) via U_SG assessment in combat sport athletes, often in spite of stable body-mass. Given the widespread use in both research and practice, and its use in a regulatory sense as a ‘hydration test’ in combat sports as a means to detect dehydration at the time of weigh-in; understanding the limitations and applicability of U_SG assessment is of paramount importance. Inconsistencies in findings of U_SG readings, possibly as a consequence of diverse methodological research approaches and/or overlooked confounding factors, preclude a conclusive position stand within current combat sports research and practice. Thus the primary aim of this paper is to critically review the literature regarding U_SG assessment of hydration status in combat sports research and practice. When taken on balance, the existing literature suggests: the use of laboratory derived benchmarks in applied settings, inconsistent sampling methodologies, the incomplete picture of how various confounding factors affect end-point readings, and the still poorly understood potential of renal adaptation to dehydration in combat athletes; make the utility of hydration assessment via U_SG measurement quite problematic, particularly when diet and training is not controlled.     

The Role of Attention in the Development of Short-Term Memory: Age Differences in the Verbal Span of Apprehension

In previous studies of memory span, participants have attended to the stimuli while they were presented, and therefore have had the opportunity to use a variety of mnemonic strategies. In the main portion of the present study, participants (first- and fourth-grade children, and adults; 24 per age group) carried out a visual task while hearing lists of spoken digits and received a post-list digit recall cue only occasionally, for some lists. Under these conditions, list information presumably must be extracted from a passively held store such as auditory sensory memory. The results suggest that each individual has a core memory capacity limit that can be observed clearly in circumstances in which it cannot be supplemented by mnemonic strategies, and that the capacity limit appears to increase with age during childhood. Other, attention-demanding processes also contribute to memory for attended lists.