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Training in the matrix: introducing a combined program for youth soccer players development
No full textINTRODUCTION High-intensity technical actions heavily influence the outcome of soccer matches. While performance factors are traditionally trained separately, we proposed a program combining technique and agility (combination of strength, speed, balance and coordination, (Sheppard and Young (2006)) for youth players’ development. We assessed the effect of this program on motor and technical skills. METHODS The program was structured on a 14x12-m matrix of elastic tapes (lifted at 25 cm) that provides a constraints-driven reference for movement timing and techniques. Practices were aimed to develop game-like high-intensity technical actions with the ball. Twenty U12 sub-elite male soccer players (41.8±7.1 kg, 1.55±0.08 m) from to the same club were randomly assigned to an experimental (EG) and a control group (CG). A repeated-measures design was used: the EG was exposed to 20-40 min/session of differentiated training (22 weeks, 38 sessions) while the CG continued the traditional training. Shuttle Dribbling Test (SDT, Huijgen et al. (2010)) and the Loughborough Soccer Passing Test (LSPT, Ali (2011)) were performed before and after the differentiated training. Medians and interquartile ranges (IQR) of percentage change between measurements, correlation coefficients (r) with individuals’ stature increments and Cohen’s d effect size were computed. RESULTS The stature increment between measurements was 3.5 (IQR 0.1) cm for the CG and 3.8 (0.2) cm for the EG (d=0.11). In the SDT, the EG improved by 4.1%, while the CG performance decreased by 0.6% (d=0.97); in the LSPT, EG improved by 6.8% while the CG by 0.3% (d=0.78). Performance and stature changes were moderately-to-low correlated (CG vs. EG): r=0.35 vs. -0.17 (SDT); r=0.41 vs. 0.18 (LSPT). DISCUSSION The matrix was designed to stress dynamic balance, quick changes-of-direction, and specific agility/coordination skills: the program produced higher performance improvements, compared to traditional training, in 180°-changesof-direction and in a controlling and passing dynamic task. It seemed to balance the losses in coordination caused by the adolescent motor awkwardness (Quatman-Yates et al., 2012). The program acts simultaneously on the physical, technical and perceptual corners of soccer performance, thus optimizing the training process. Despite more age/proficiency levels have to been considered, the methodological implications of this study could be beneficial for youth training effectiveness. REFERENCES Ali A (2011). Scand J Med Sci Sports, 21, 170–183 Huijgen BCH, et al. (2010). J Sports Sci, 28, 689–698. Quatman-Yates CC, et al. (2012), Br J Sports Med, 46, 649-655. Sheppard and Young (2006), J Sports Sci, 24, 919-932. CONTACT [email protected]
Effects of a combined technique and agility program on youth soccer players skills
No full textHigh-intensity actions with high technical demands heavily influence soccer game outcomes. While performance factors have been traditionally trained separately, a program combining agility and technique training was proposed, structured on artificial constraints (tapes) creating spatiotemporal restrictions. This repeated-measures study involved an experimental and a control group: 20 Under-12 sub-elite male soccer players were tested before and after a 22-weeks differentiated training intervention or the traditional training schedule. The proposed program produced higher performance improvements, compared to traditional training, in the Shuttle Sprint Test (two-way analysis of variance, factors: Group and Time, significant Group Time interaction, P < 0.05) and in the Loughborough Soccer Passing Test execution time (4.8%, P < 0.05). Both groups improved Slalom Dribbling Test performance (P < 0.001). We concluded that the proposed program could enhance performance in 180 change-of-direction and in the time to complete a controlling and passing dynamic task. The methodological implications of this study could be beneficial in improving youth soccer training effectiveness
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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