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Purpose: To assess the effects of two different physical education teaching strategies on promoting improvements in students' volleyball gameplay performance. Methods: A sample of 81 secondary school students (mean age: 14.7 years) were divided into a game-based group (n = 45), which experienced PE lessons based on Tactical Games Model (TGM), and a skill-based group (n = 36), which followed their traditional PE lessons based on directive- and drill-oriented approach. Psychomotor performance indexes (i.e., decision-making, skill execution, support, game play) were assessed by means of the Game Performance Assessment Instrument prior to, and at the end of, 18 lessons. 2 (group) × 2 (time) repeated measure MANOVA was conducted to examine the effects of teaching, time, and their interaction on gameplay components. Non-clinical magnitude-based inference method was used to interpret the main effects of these models. Results: Between-group analysis revealed significant changes for the index of support (p = 0.02, very likely) in the game-based group, while within-group results revealed significant improvements in decision-making (p < 0.001, most likely) and support indexes (p = 0.02, very likely). Finally, the significant interaction term was related to an overall improvement of decision-making (p = 0.001, most likely), skill execution (p = 0.01, very likely), and support (p = 0.005, most likely) for the game-based group in post-test. Conclusion: Findings support the use of the TGM throughout physical education in high school in extent to which the students improved in learning outcomes that are closely related to the real volleyball context, in a better understanding of the tactical awareness and, as a consequence, in better sport performances. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the effects of a tactical games model instructional plan on game-play volleyball performances of elementary school students, taking into account their skill level. In total, 39 fourth-grade students (average age: 8.9 years) participated in a 13-week unit, in which each lesson exaggerated the use of small-sided games. In-game performances were assessed via the Team Sport Assessment Procedure, while students played a 10-minute modified game (four versus four). Data were collected pre- and post-intervention, and after the summer vacation (retention test). A 2 (skill level) × 3 (time) analysis of variance with repeated measures was used to compare students' performance, and the relevant effects were interpreted mainly by means of confidence intervals and effect size measures. At the end of the instructional period, all participants had an overall moderate to large improvement, and this global improvement seems to have remained at least until the end of the summer vacation. Lower-skilled students attained a larger and more established improvement than high-skilled students did. However, some detrimental effects on in-game students' performance existed at the end of the instructional period. Therefore, teachers have to take into account students' skill levels when designing their lessons because, if small-sided games are adequately considered and managed, students' learning processes can be enhanced. Furthermore, the students should be assigned appropriate learning activities to avoid summer learning loss in physical education. [ABSTRACT FROM AUTHOR]

The aim of this study was to verify whether the Nintendo Wii-Balance-Board was valid and reliable for assessing sit-to-stand and return-to-sit tasks by comparing it with a gold-standard force plate. Ten elderly (age = 78.21±14.82 years; males=4; females=6) and eleven young (age = 24.25±12.43 years; males=6; females=5) participants of both genders performed five sit-to-stand and return-to-sit tasks consecutively by placing their feet on the Wii-Balance-Board; after two days of rest, they repeated the same assessment. The Wii-Balance- Board was positioned over the force plate to concurrently acquire the vertical component of ground reaction forces. Relevant kinetic and temporal parameters were estimated from these signals. Both the Wii-Balance- Board and force plate measurements resulted in a high level of correlation for almost all the parameters (Pearson's product-moment r ranged from 0.91 to 0.99, p<.001) and, for the same parameters, intra-class correlation coefficients revealed a high level of agreement between the devices (ranged from 0.93 to 0.99). Bland-Altman plots and regression analysis detected systematic and fixed biases for two parameters (i.e., the inclination of force in standing and rising), while other parameters resulted with none systematic biases; the absolute magnitude of those differences was trivial or small (standardized biases ranged from 0.01 to 0.4). A high level of intra-device reliability was measured for all the parameters (intra-class correlation coefficients ranged from 0.85 to 0.99). The Wii-Balance-Board proved valid and reliable in comparison with a force plate for assessing transition movements so it can be considered a valuable solution for supporting the assessment procedures of average practitioners. [ABSTRACT FROM AUTHOR]

This study tested the feasibility of using an inertial measurement unit to discriminate different developmental levels of children performing the standing long jump (SLJ). Sixty-four children (54.6% boys, 46.4% girls) aged 8 to 11 years old (M = 9.17, SD = 0.97) performed the SLJ three times and were classified by rater observations into three developmental levels. Concurrently, they wore an inertial measurement unit from which a set of temporal and kinematic parameters for the quantitative assessment of their jumps. A multivariate analysis of variance revealed that variability among the developmental groups was identified by the overall set of parameters, while discriminant function analysis verified that these parameters discriminated among developmental levels. Primary predictors for developmental group discrimination were maximum peak acceleration in the vertical and anteroposterior directions, respectively, and normalized preparation time. These outcomes represent significant steps toward improving the assessment of SLJ rate of development in childhood and supporting physical education. [ABSTRACT FROM AUTHOR]

The aim of this study was to identify the independent and interactive effects of possession strategy, pitch location, and game period on the offensive actions performed by the winning teams in the 2012 European Football Championship. The non-clinical magnitude-based inferences method was used to interpret the true effect of the performance indicators on the response variable. The offensive team possessions were grouped into winning (n = 2035) and losing (n = 2071). The winning teams performed offensive processes mainly using the possession play strategy (OR: 0.75, very likely negative effect of the direct play). When the analysis included the pitch location, negative interaction effect was found for the direct play, which ended up in the central path (OR: 0.70, very likely negative effect). On the contrary, the direct play in the second half of the match seemed to produce an effect on the probability of the winning teams performing offensive processes (OR: 1.59, most likely positive effect). The results of multivariate analyses showed that the offensive team possession profiles required a careful investigation because the possession strategy changed under the conjoint effect of pitch location and game period. [ABSTRACT FROM AUTHOR]

Balance and mobility assessment, and the estimation of the risk of falls, represent crucial elements for supporting a healthy aging process. In this work, we evaluated the association of two approaches used to estimate standing balance and sit-to-stand abilities in community-dwelling older people. The clinical-based test was the Short Physical Performance Battery, while the laboratory-based assessments were realized by means of output measures obtained with the Wii Balance Board. The correlation between clinical scores and laboratory measures showed poor association for the standing balance test (.05

Summary.—Understanding the developmental levels of fundamental movement skills has a critical role in the improvement of motor competence in childhood. In this respect, the use of Microsoft Kinect to assess vertical jumping skill and to predict developmental levels in 9- to 12-yr.-old children was evaluated. 41 boys and girls repeated the countermovement jump test three times. Vertical jumping skill levels were categorized using observational records, while kinematic and temporal parameters were estimated using a biomechanical model based on data acquired by the Kinect. Multivariate analysis of variance (MANOVA) and discriminant analysis verified that the height of the jump and the flight height predict the primary differences in jumping skill developmental levels, and the Kinect-based assessment discriminates these levels. [ABSTRACT FROM AUTHOR]

Abscission is the final step of cytokinesis whereby the intercellular bridge (ICB) linking the two daughter cells is cut. The ICB contains a structure called the midbody, required for the recruitment and organization of the abscission machinery. Final midbody severing is mediated by formation of secondary midbody ingression sites, where the ESCRT III component CHMP4B is recruited tomediate membrane fusion. It is presently unknown how cytoskeletal elements cooperate with CHMP4B to mediate abscission. Here, we show that F-actin is associated with midbody secondary sites and is necessary for abscission. F-actin localization at secondary sites depends on the activity of RhoA and on the abscission regulator citron kinase (CITK). CITK depletion accelerates loss of F-actin proteins at the midbody and subsequent cytokinesis defects are reversed by restoring actin polymerization. Conversely, midbody hyperstabilization produced by overexpression of CITK and ANLN is reversed by actin depolymerization. CITK is required for localization of F-actin and ANLN at the abscission sites, as well as for CHMP4B recruitment. These results indicate that control of actin dynamics downstream of CITK prepares the abscission site for the final cut. [ABSTRACT FROM AUTHOR]

In neuronal cells, actin remodeling plays a well known role in neurite extension but is also deeply involved in the organization of intracellular structures, such as the Golgi apparatus. However, it is still not very clear which mechanisms may regulate actin dynamics at the different sites. In this report we show that high levels of the TTC3 protein, encoded by one of the genes of the Down Syndrome Critical Region (DCR), prevent neurite extension and disrupt Golgi compactness in differentiating primary neurons. These effects largely depend on the capability of TTC3 to promote actin polymerization through signaling pathways involving RhoA, ROCK, CIT-N and PIIa. However, the functional relationships between these molecules differ significantly if considering the TTC3 activity on neurite extension or on Golgi organization. Finally, our results reveal an unexpected stage-dependent requirement for F-actin in Golgi organization at different stages of neuronal differentiation. [ABSTRACT FROM AUTHOR]

Abstract: KRIT1 is a disease gene responsible for Cerebral Cavernous Malformations (CCM). It encodes for a protein containing distinct protein–protein interaction domains, including three NPXY/F motifs and a FERM domain. Previously, we isolated KRIT1B, an isoform characterized by the alternative splicing of the 15th coding exon and suspected to cause CCM when abnormally expressed. Combining homology modeling and docking methods of protein-structure and ligand binding prediction with the yeast two-hybrid assay of in vivo protein–protein interaction and cellular biology analyses we identified both structural and functional differences between KRIT1A and KRIT1B isoforms. We found that the 15th exon encodes for the distal β-sheet of the F3/PTB-like subdomain of KRIT1A FERM domain, demonstrating that KRIT1B is devoid of a functional PTB binding pocket. As major functional consequence, KRIT1B is unable to bind Rap1A, while the FERM domain of KRIT1A is even sufficient for this function. Furthermore, we found that a functional PTB subdomain enables the nucleocytoplasmic shuttling of KRIT1A, while its alteration confers a restricted cytoplasmic localization and a dominant negative role to KRIT1B. Importantly, we also demonstrated that KRIT1A, but not KRIT1B, may adopt a closed conformation through an intramolecular interaction involving the third NPXY/F motif at the N-terminus and the PTB subdomain of the FERM domain, and proposed a mechanism whereby an open/closed conformation switch regulates KRIT1A nuclear translocation and interaction with Rap1A in a mutually exclusive manner. As most mutations found in CCM patients affect the KRIT1 FERM domain, the new insights into the structure–function relationship of this domain may constitute a useful framework for understanding molecular mechanisms underlying CCM pathogenesis. [Copyright &y& Elsevier]