Studies focused on position-related characteristics of young soccer players often ignore the goalkeepers. The aim of this study was to examine the effect of playing position on anthropometry, physiological attributes, soccer skills, and goal orientation across adolescence. One hundred forty-five soccer players age 11–19 y were assessed in training experience, body size, maturation, physiological parameters, soccer skills, and goal orientation. Factorial ANOVA was used to test the effect of age group, playing position, and respective interaction terms, while analysis of variance was used to compare goalkeepers vs outfielders in middle (under 13 [U-13] and U-15) and late (U-17 and U-19) adolescence. Discriminant analysis was used to identify the variables that contributed to explaining playing positions. Age group was a consistent source of variation for all variables except task and ego orientations. Fat mass, agility, endurance, dribbling speed, shooting accuracy, and passing were affected by the gradient derived from the classification between goalkeepers and outfielders. It was possible to correctly classify the playing position based on fat-free mass and 3 manipulative skills in younger players and on 4 skills in U-17 and U-19 soccer players. Future research should include longitudinal information to improve our understanding of the factors that contribute to distinguish goalkeepers from outfielders.
Ricardo Rebelo-Gonçalves, Manuel João Coelho-e-Silva, Vítor Severino, Antonio Tessitore and António José Barata Figueiredo
Tiago M. Barbosa, Jorge E. Morais, Mário J. Costa, José Goncalves, Daniel A. Marinho and António J. Silva
The aim of this article has been to classify swimmers based on kinematics, hydrodynamics, and anthropometrics. Sixty-seven young swimmers made a maximal 25 m front-crawl to measure with a speedometer the swimming velocity (v), speed-fluctuation (dv) and dv normalized to v (dv/v). Another two 25 m bouts with and without carrying a perturbation device were made to estimate active drag coefficient (CD a). Trunk transverse surface area (S) was measured with photogrammetric technique on land and in the hydrodynamic position. Cluster 1 was related to swimmers with a high speed fluctuation (ie, dv and dv/v), cluster 2 with anthropometrics (ie, S) and cluster 3 with a high hydrodynamic profile (ie, CD a). The variable that seems to discriminate better the clusters was the dv/v (F = 53.680; P < .001), followed by the dv (F = 28.506; P < .001), CD a (F = 21.025; P < .001), S (F = 6.297; P < .01) and v (F = 5.375; P = .01). Stepwise discriminant analysis extracted 2 functions: Function 1 was mainly defined by dv/v and S (74.3% of variance), whereas function 2 was mainly defined by CD a (25.7% of variance). It can be concluded that kinematics, hydrodynamics and anthropometrics are determinant domains in which to classify and characterize young swimmers’ profiles.
Ana Katherine Gonçalves, Gilzandra Lira Dantas Florêncio, Maria José Maissonnete de Atayde Silva, Ricardo Ney Cobucci, Paulo César Giraldo and Nancy Michelle Cote
Observational studies have reported an association between physical activity and breast cancer risk reduction. This study aims to evaluate the effect of physical activity on breast cancer prevention.
Articles were identified through literature available on Electronic databases (Pubmed, Embase, Scielo, Cochrane, CINAHL, Cancerlit, and Google Scholar) and manual searches. Case control and cohort studies were assessed for methodological quality, using the Newcastle-Ottawa scale.
Size, population, components, and characteristics of physical activity, and menopausal status were documented. Review Manager 5.1 performed analysis using the statistical method of Mantel-Haenszel. Fixed-effect analysis with dichotomous data, testing subgroups and calculating odds ratio with a confidence interval of 95% were used. Main results: 7 cohort studies and 14 case control studies were evaluated. Statistical evidence found that physical activity reduces the risk of breast cancer in case-control studies [OR = 0.84 (0.81–0.88)] (heterogeneity 72%) and cohort studies [OR = 0.61 (0.59–0.63)] (heterogeneity 100%).
Physical activity seems to prevent breast cancer mainly in postmenopausal women.