Physiological and Anatomical Characteristics Of Outstanding Female Junior Tennis Players

Purpose: The purpose of this study was to investigate the physiological adaptations of resistance training (RT) in prepubertal boys. Methods: Eighteen healthy boys were divided into RT (n = 9, M_age = 10.4 ± 0.5 years) and control (CTR; n = 9, M_age = 10.9 ± 0.7 years) groups. The RT group underwent a resistance training during 12 weeks, 3 times per week, performing 3 sets of 6 to 15 repetitions at intensities ranging from 60% to 80% of maximal dynamic strength (1-repetition maximum [1-RM] values). Before and after the training, the groups were assessed in their body mass and composition (dual-energy X-ray absorptiometry), isokinetic dynamometry, 1-RM, and ergoespirometry. Moreover, force per unit of muscle volume was calculated by the quotient between 1-RM and lean mass. Results: Both groups presented statistically significant (p < .05) increases in the 1-RM and force per unit of muscle volume in the knee extension and elbow flexion, but these strength increases were statistically significantly greater in the RT group (effect size [ES] = 2.83–9.00) than in the CTR group (ES = 0.72–1.00). Moreover, both groups statistically significantly increased in lean body mass variables (ES = 0.12–0.38). However, increases in the fat mass variables occurred only in the CTR group (ES = ? 0.01–0.50), whereas no changes were observed in the RT group. Furthermore, there were statistically significant increases in all bone mineral content variables (ES = 0.13–0.43), without differences between groups. No cardiorespiratory changes were observed. Conclusion: Twelve weeks of RT was effective in improving strength and force per unit of muscle volume and prevented fat mass increases in boys.     

Preschool and Children's Outcomes in Elementary School: Have Patterns Changed Nationwide Between 1998 and 2010?

This study employs data from both kindergarten cohorts of the Early Childhood Longitudinal Study (n ~ 12,450 in 1998; n ~ 11,000 in 2010) to assess whether associations between preschool participation and children's academic and behavioral outcomes—both at school entry (M_age = 5.6 years in both cohorts) and through third grade—have changed over time. Findings are strikingly similar across these two, nationally representative, U.S. cohorts: preschool is positively associated with academic outcomes and negatively associated with behavioral outcomes both at school entry and as children progress through school. Heterogeneity is documented with respect to child and preschool characteristics. However, there is no evidence that associations between preschool and medium-term child outcomes differ by elementary school characteristics.     

We Don't Say “H” Here

This article is focused on building interdependence among diverse learners through four specific engagements in the art room: Friend/Family Involvement, Team-Building, Leadership Habits, and Service Learning. These strategies have been beneficial to the author in creating a sustainable model for high-quality visual arts instruction.     

Gahvora cradling in Tajikistan: Cultural practices and associations with motor development

In Tajikistan, infants are bound supine in a “gahvora” cradle that severely restricts movement. Does cradling affect motor development and body growth? In three studies (2013–2018), we investigated associations between time in the gahvora (within days and across age) and motor skills and flattened head dimensions in 8–24-month-old Tajik infants (N = 269, 133 girls, 136 boys)) and 4.3–5.1-year-old children (N = 91, 53 girls, 38 boys). Infants had later motor onset ages relative to World Health Organization standards and pronounced brachycephaly; cradling predicted walk onset age and the proficiency of sitting, crawling, and walking. By 4–5 years, children's motor skills were comparable with US norms. Cultural differences in early experiences offer a unique lens onto developmental processes and equifinality in development.