In team sports. Jumping tests have been used as predictors of COD; however, there are not too many studies analyzing how dominance affects the best performance of the turn. The purpose of this study was to explore the relationship between tests pertaining to jumps (1 and 2 legs) and COD (right and left turns). Forty-two male students were selected at the Faculty of Physical Education (age: 20.1 ± 3.7 years; weight: 73.4 ± 8.4 kg; body mass index: 23.1 ± 2.6 kg·m−2; and fat mass: 17.1 ± 8.8%). All the subjects had right leg dominance. The COD tests were assessed using three 10-m sprint tests (90° right and left turns and 180° turn). Jumps were countermovement jumps (CMJs with 1 and 2 legs) and the drop jump (DJ). Pearson coefficient correlation and stepwise regression analyses were performed. Our results showed that both CMJs and DJs were associated with COD. The CMJ with the right leg had the best coefficient correlation with left COD time (r = −0.64; p < 0.01). Also, the CMJ was associated with COD180° time (r = −0.60; p < 0.01). After regression analysis, only right one-leg CMJ and CMJ were predictors of left COD time (adjusted R2 = 0.46; p < 0.01). The main finding of this study was that the CMJ, but not the DJ, was the best predictor of dominant side COD. Jumps are an important component of team sport training because they improve COD performance. However, coaches use several types of jumps during training; our results suggest that jumps similar to the CMJ should be useful tools to improve COD, which helps to specify better training prescription....

Paddle-tennis is a racket sport practised by 4.5 million people around the world and it is increasing each year. The aim of this study was to analyse physical responses, i.e., partial and total distances covered, and physiological responses, i.e., mean heart rate (HR), rating of perceived exertion (RPE) and lactate, during competition. Sixty sets were analysed on twenty-four male paddle-tennis players. Differences in physical and physiological variables were evaluated using one way ANOVA. High level players (C1) covered lower distance than middle (C2) and lower level (C3) players during set and match play (P<0.05). In addition, HR in C1 was 131.7±16.3 beats/min and versus 156.4±15.6 and 150.8±14.4 beats/min of C2 and C3, respectively (P<0.05). Finally, C1 remained 43.7% and 12.9% of the playing time in HR2 (50-70% of maximum HR) and HR4 (80-90%of maximum HR) zones, respectively; while that C2 and C3 registered 15-20% and 30-32% in HR2 and HR4 zone, respectively (P<0.05). RPE was also significantly lower in C1 with regard to the one found in C2 and C3. These results reveal that C1 shows lower physical and physiological responses than C2 and C3, and these responses are similar to single tennis and table-tennis sports but lower than squash and badminton in match play.

Cárdenas-Fernández, V, Chinchilla-Minguet, JL, and Castillo-Rodríguez, A. Somatotype and body composition in young soccer players according to the playing position and sport success. J Strength Cond Res 33(7): 1904–1911, 2019—Soccer players undergo an evolution in their body composition throughout the growth and passage through the different base stages, that is, childhood, puberty, and adolescence. The aim of this study was to analyze the morphology and body composition of U14, U16, and U19 soccer players, taking into account in addition, their sport success endorsed through the regularity participation and their relation with the different playing positions occupied during competition (goalkeeper, external defender, central defender, midfielder, and forward/extreme). For that, a total of 174 male young soccer players were evaluated anthropometrically. Dominant somatotype of the players was, according to their playing position, meso-endomorphic in goalkeepers, central for external defenders, balanced ectomorph in central defenders, balanced mesomorph in the case of midfielders, and meso-ectomorph in forwards/extremes. Taking into account that sport performance is directly mediated by the body composition of athletes, the differences found suggest a marked specialization between the goalkeepers and forwards, establishing significant differences between them. Further studies would be needed to evaluate the influence of individual maturation development vs. sports training on the conformation of a certain anthropometric profile of a soccer player and its relation with the different playing positions occupied on the pitch during the game.

Background: The purpose of this study was to examine the differences in anthropometric measurements using an aerobic and Pilates exercise program which lasted 24 weeks. Method: This was a clinical intervention study of 303 women over the age of 60 living in Novi Sad, Serbia. Changes in body mass index and skinfold thickness were estimated through height, weight, and anthropometric measurements. The program comprised Pilates exercises for upper- and lower-body strength, agility, and aerobic capacity. Results: Fat mass (FM) improved significantly (pre-test, 32.89%, 8.65; post-test, 28.25%, 6.58; P0.05), but there was a higher correlation between FM (%) and waist–hip ratio (rho, 0.80; P<0.01). Conclusion: A mixed program of aerobics and Pilates, controls and improves baseline muscle mass and decreases FM values, without causing deterioration during practice and follow-up exercises.

Self-concept influences identity and the way that people behave, and it fluctuates over time. The main purpose of this study was to analyze fluctuations in the dimensions of self-concept as a function of gender, educational level, grade, age, physical activity, and weight. In total, 712 Spanish adolescents who were in the 5^th and 8^th grades (354 boys and 358 girls) and 10 to 14 years old (M = 11.9; SD = 1.3) participated in this study. The Self-Concept Questionnaire, Form 5 was used to analyze several dimensions of self-concept (academic, social, emotional, family, and physical), using the average scores in each dimension. The data showed strong differences in the dimensions of self-concept during the school transition. Middle-school students, compared to elementary-school students, showed significantly lower levels in almost all dimensions (academic, social, family, and physical). Furthermore, student age was a negative predictor of the social and academic dimensions, explaining 33% and 37% of the variance, respectively. Educational level and grade were smaller factors influencing the academic dimension (explaining 29% and 25% of the variance, respectively). The main findings revealed that the school transition and, specifically, increased age were associated with a lower self-concept. These results help us understand the need to strengthen psychological and educational self-concept at school.

Various nutritional strategies are adopted for athletes to maintain and to improve performance during the competition season. Betaine may enhance performance during a competitive season by increasing the testosterone to cortisol ratio and reducing systemic inflammation. The aim of this study was to investigate the effect of betaine supplementation on the bio-motor abilities in young professional soccer players. Twenty-nine young professional soccer players (age, 15.5±0.3 years) were matched by position and randomly assigned to one of two groups for 14 weeks: betaine (BG, 2 g/day; n=14) or placebo (PG n=15). Diet was standardized by a nutritionist, and measures of muscular power (countermovement jump: CMJ), change of direction: modified 5-0-5), acceleration (10 m sprint), sprint performance (30 m sprint time: SpT), muscular strength (leg press and bench press one repetition maximum: 1-RM), repeated sprint ability (running-based anaerobic sprint test: RAST), and aerobic capacity (30-15 intermittent fitness test) were assessed in the pre (P1), mid (P2) and post (P3) season over the course of 5 days. All subjects participated in one soccer match and five training sessions per week. Significant (p < 0.05) group x time interactions were found for maximal oxygen uptake (VO2max), anaerobic peak power, and muscular strength favoring BG at P2 and P3 compared to P1. There were meaningful (p < 0.05) group x time interactions for CMJ, SpT, and peak power during the RAST that favored the BG. 14-week of betaine supplementation increased predicted 1-RM, VO2max, and repeated sprint ability performance in youth professional soccer players. Betaine supplementation seems to be a useful nutritional strategy to improve and to maintain performance during a competitive soccer season.