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Is self-administered rating scale for pubertal development a predictor of countermovement jump in young soccer players?
Full text linkObjective: Considering that in Young sport competitions children are divided according to their chronological age, the aim of this study was to examine the correlation among chronological age and Self-Administered Rating Scale for Pubertal Development (PDS), anthropometry (Body Mass Index -BMI-, percent body fat -%BF-, fat free mass -FFM-), and Countermovement jump (CMJ) measures. Methods: 112 young soccer players (age: 14±2 yrs; height: 1.68±0.11 m; weight: 60.3±11.6 kg; BMI: 21.3±2.5 kg.m-2) grouped in “Giovanissimi” (12-14 yrs), “Allievi” (15-16 yrs), and “Juniores” (>17 yrs), categories were evaluated. Pearson correlations and stepwise multiple regression analysis among variables were calculated considering all subjects and within categories. The internal consistency of PDS was determined by Cronbach’s α coefficient (Cα). Considering all subjects, PDS showed an excellent Cα (0.89) and significant correlations with sub-category (r=0.66), age (r=0.67), %BF (r=-0.31), FFM (r=0.71), and CMJ (r=0.55). Within “Giovanissimi” category, significant correlations were found between PDS and age (r=0.56), CMJ (r=0.33), FFM (r=0.63), and subcategory (r=0.55). In “Allievi”, PDS showed correlations with CMJ (r=0.46), FFM (r=0.42), and %BF (r=-0.45). In “Juniores” no significant correlations between PDS and other variables were present. The regression model with sub-category, PDS, and %BF as predictors explained 41% of the variance of CMJ in all subjects. In the “Allievi” category the PSD was the only predictor explaining the 18% of the CMJ performance variance. Results: PDS can provide useful information for the coach to create individual conditioning programs taking into account the growth problems of young soccer players and to minimize the risk of an excessive workloa
Relationship among explosive power, body fat, fat free mass, and pubertal development in youth soccer players. A preliminary study
No full textPurpose Changes in body size and functional capacities
are highly individual during puberty, and the performance
of a soccer player is often closely related to their maturity
status. The aim of the study was to evaluate the relationships
among explosive power, body fat, fat free mass and
pubertal development in young soccer players.
Methods Explosive power (countermovement jump—
CMJ), body mass index (BMI), percentage of body fat
(%BF), fat free mass (FFM) and a Self-Administered
Rating Scale for pubertal development (PDS) values of 11
‘‘Giovanissimi’’ (age 13 year), 13 ‘‘Allievi’’ (age 15 year)
and 10 ‘‘Juniores’’ (age [17 year) male soccer players
were compared. The statistical analysis was performed
using an analysis of variance among categories with
Fisher’s post hoc as appropriate. Furthermore, Pearson
correlations among variables were calculated considering
all subjects and also within categories.
Results Statistical differences emerged among categories
in CMJ (F(2,30) = 28.3, p\0.01), body fat weight (F(2,31) =
29.2, p\0.01) and PDS (F(2,29) = 18.5, p\0.01), while
%BF values showed statistical differences only for ‘‘Giovanissimi’’
and ‘‘Juniores’’ (F(2,31) = 3.4, p = 0.01). CMJ
showed significant correlations with FFM (r = 0.68) and
PDS (r = 0.63), PDS with FFM (r = 0.66) and BMI with
%BF(r = 0.71) and FFM (r = 0.71).A high correlation was
found within categories.
Conclusion Since we found differences between categories
and no correlation between chronological age and
pubertal status, this study highlights the importance of
assessing of puberty in youth soccer team
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
CORRELAZIONE TRA ETÀ CRONOLOGICA, SVILUPPO PUBERALE, COMPOSIZIONE CORPOREA E PRESTAZIONI ESPLOSIVE IN GIOVANI CALCIATORI
No full textConsiderando che le competizioni sportive giovanili sono organizzate sulla base dell’età cronologica, l'obiettivo di questo studio è stato quello esaminare possibili correlazioni tra età cronologica, misure antropometriche (peso ed altezza), indice di massa corporea (BMI), percentuale di grasso corporeo (¿), massa magra (FFM), sviluppo puberale (PDS), e salto con contromovimento (CMJ) di 112 giovani calciatori (età: 14±2 anni, altezza: 168±11 cm, peso: 60.2±11.6 kg, BMI: 21.3±2.5 kg.m-2) raggruppati nelle categorie Giovanissimi "A" (14 anni), "B" (13 anni) e "C"(12 anni), Allievi "A" (16 anni) e "B" (15 anni) e Juniores (>17 anni). L’indice di correlazione di Pearson calcolato tra le variabili, ha evidenziato correlazioni significative tra tutte le variabili. In particolare, l’età cronologica ha dimostrato alte correlazione con CMJ (r = 0.59), PDS (r = 0.69), e FFM (r = 0.76). All'interno della categoria Giovanissimi è stata trovata correlazione tra età cronologica e CMJ (r = 0.45), FFM (r = 0.62) e PDS (r = 0.56), mentre negli Allievi sono state osservate moderate correlazioni tra l'età cronologica e FFM (r = 0.36), BMI (r = 0.37). Contrariamente ai Giovanissimi, negli Allievi il CMJ ha dimostrato correlazione con il PDS (r= 0.46). Nella categoria Juniores una correlazione molto grande è stata trovata tra il BMI con FFM (r=0.63) e con ¿ (r=0.84). Considerando che la variabilità dello sviluppo puberale nella categoria Allievi, unita a specializzazione precoce e carichi di lavoro inadeguati, contribuisce ad aumentare il rischio di infortuni durante l'adolescenza, l'allenatore dovrebbe tener conto delle esigenze e dei problemi di crescita dei giovani calciatori e creare programmi individualizzati di condizionamento
Relationship among performance value, body fat, fat free mass and pubertal development in youth soccer players
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