Physical activity levels are associated with regional bone mineral density in boys.

Background: Youth is a crucial period for bone gain, and physical activity (PA) has shown to increase bone mineral density (BMD) in this period. However, whether PA affects regional BMD is unclear. Thus, the aim of this study was to analyze the relationship between PA levels and regional BMD in youths. Methods: The sample included 110 children and adolescents aged 6-14 years. Body mass, height, sitting trunk length, and leg length were obtained for body mass index and maturity offset calculation. The arms, pelvis, spine, trunk, and legs BMD were measured by double energy X-ray absorptiometry. The PA was evaluated by questionnaire, and youths were classified as low, moderately, or highly physically active. Results: The sample included 63.7% boys and 36.3% girls with mean age of sample 9.5 (±1.6) yrs. Age, body mass index, and maturity offset were similar between sexes (p > 0.05). Boys with low PA levels had lower BMD Z-score for arms (-0.20 ± 0.71 vs. 0.30 ± 1.19, p = 0.006) and legs (-0.14 ± 1.00 vs. 0.35 ± 1.06, p = 0.026) compared to highly physically active youths. Multiple linear regression showed a positive linear relationship between legs BMD and PA in boys (ß = 0.72 [95% CI = 0.09; 1.36]). Conclusion: In boys, low PA levels are associated with lower BMD in arms and legs.

Effects of 9 Months of Martial Arts Training on Cardiac Autonomic Modulation in Healthy Children and Adolescents.

PURPOSE: The aim of the study was to evaluate the cardiac autonomic modulation after 9 months of martial arts practice in healthy children and adolescents. METHOD: The study included 59 children and adolescents who were divided into 3 groups: judo, Muay Thai, and control. Heart rate variability was measured by a heart rate monitor, model Polar RS800CX. The intervention occurred twice a week on nonconsecutive days, lasting 60 minutes each session. A 1-way analysis of variance was used to compare participants at baseline. The comparisons between groups at baseline and after the intervention were carried out by a 2-way analysis of variance for repeated measures. RESULTS: After 9 months of intervention, significant increases were observed for root mean square successive differences, with higher values post compared with baseline (19.5%; P = .04). For SD1, an interaction effect was observed, with increased posttraining values compared with baseline (24.1%; P = .04) for the judo group. Qualitative analysis of the Poincaré plot showed greater dispersion of RR intervals, mainly beat to beat, after the judo intervention compared with the baseline. The Muay Thai and control groups presented no improvement. CONCLUSION: After 9 months of intervention, there were increases in cardiac autonomic modulation of children and adolescents participating in judo training. The practice of martial arts, such as judo, can be encouraged from an early age to improve cardiovascular system functioning, possibly providing protection against cardiovascular problems.

Physical activity of parents and of their children: a systematic review of Brazilian sample studies - Report Card Brazil / Atividade física de pais e filhos: uma revisão sistemática de estudos com amostras brasileiras - Report Card Brazil

Abstract The aim of this study was systematically review the researches in regard the association of PA of parents and the PA of their children. A literature search was performed in five databases (Medline, Embase, Cinahl, Lilacs and SciELO) using combined terms about youth, PA and social support, with restriction to publications with Brazilian sample and to English and Portuguese language. Thirteen studies were included in this review and was observed a positive association of parental PA and the PA of their children for the majority of the studies (n=11). Only two studies did not observed significant association between PA of parents and their children and, otherwise, it was not observed negative associations in the review. It was observed different associations according to the gender of both parents and children. This findings support the importance for the practice of PA by parents as encouragement for the practice of PA by their children among Brazilians. The strategies to promote the increase in practice of physical activity of children and adolescents of both genders may consider the social support as an important factor, especially in relation to the practice of PA of their parents.

Resumo O objetivo do presente estudo foi revisar sistematicamente estudos que analisaram a associação da prática de atividade física de pais e filhos. Foi realizada uma busca sistemática em cinco bases de dados (Medline, Embase, Cinahl, Lilacs e SciELO), por meio da combinação de termos sobre crianças e adolescentes, atividade física e suporte social, sendo restrita a estudos contendo amostras brasileiras e escritos em Inglês e/ou Português. Foram incluídos treze estudos na presente revisão e foi observada associação positiva da prática de atividade física de pais e filhos na maioria dos estudos (n=11). Somente dois estudos não observaram associação significativa da atividade física de pais e filhos, contudo não foram observadas associações negativas. Foram observadas diferentes associações de acordo com o gênero tanto dos pais quanto dos filhos. Estes achados ressaltam a importância da prática de atividade física dos pais como incentivo à prática de atividade física dos filhos em amostras brasileiras. Estratégias de promoção da prática de atividade física em crianças e adolescentes de ambos os sexos devem considerar o suporte social como um fator importante, especialmente a respeito da prática de atividade física dos pais.