ABSTRACT
The current study aimed to investigate the effects of an after-school volleyball program on body composition in overweight adolescent girls. Forty-two girls were randomly divided into a volleyball group (VG) (n = 22 age: 15.6 ± 0.5 years) and control group (CG) (n = 20; age: 15.5 ± 0.7 years). Both groups continued with their usual physical education activities, while VG was included as small-sided games, two times a week, after school, on modified volleyball courts. Body mass, body mass index (BMI), body fat in kg, body fat percentage, and muscle mass were analyzed by a bioelectrical impedance method. There was a significant interaction of group (VG vs. CG) × time (pre-vs. post) for weight [F1, 40 = 7.933; p = 0.004] and BMI [F1, 40 = 5.764; p = 0.015]. Additionally, a significant main effect of time was found for body fat (kg) [F1, 40 = 17.650; p < 0.001] and body fat (%) [F1, 40 = 18.721; p < 0.001]. The results of the current study show that a twelve-week after-school volleyball program, including two sessions a week, can improve body composition in overweight adolescent girls.
ABSTRACT
With the aim of establishing the latent structure of tactical elements in the attack and defense phases of soccer 117 tactical elements of soccer were defined and their importance assessed by means of 30 variables that determine the basic segments of the game of soccer. 93 attack and 24 defense tactical elements were chosen as the entity sample and described by the 15 variables of the attack phase and 15 variables of the defense phase. Ten competent soccer experts determined the characteristics of the aforementioned entities by means of 30 variables. The experts graded from 0 to 5 the impact of every entity (tactical technique) on the individual variables that describe soccer in its phases of either attack and defense. A high level of inter-expert agreement was reached in regard to the properties of attack and defense techniques, as demonstrated by the objectivity coefficients. According to principal component factor analysis and the Kaiser and Guttman rule a total of five significant latent dimensions were obtained: finishing efficiency, ball possession performance, counter-attack efficiency, combined defense performance, and obstruction and redirection of the opposing team's attack build-up. The research partly resolved the issue of the hypothetical structure of tactical techniques in soccer by dividing the game into phases and sub-phases, attack and defense players'positions, and types (styles) of play in the attack and defense. If it is clear which movement structures have the most significant influence on the efficiency on a particular playing position and performance in the sub-phases and styles of play, it would be possible to create such training operators that will facilitate the formation of the most important motor skills in soccer.
