Global Matrix 4.0 Physical Activity Report Card Grades for Children and Adolescents: Results and Analyses From 57 Countries.

BACKGROUND: The Global Matrix 4.0 on physical activity (PA) for children and adolescents was developed to achieve a comprehensive understanding of the global variation in children's and adolescents' (5-17 y) PA, related measures, and key sources of influence. The objectives of this article were (1) to summarize the findings from the Global Matrix 4.0 Report Cards, (2) to compare indicators across countries, and (3) to explore trends related to the Human Development Index and geo-cultural regions. METHODS: A total of 57 Report Card teams followed a harmonized process to grade the 10 common PA indicators. An online survey was conducted to collect Report Card Leaders' top 3 priorities for each PA indicator and their opinions on how the COVID-19 pandemic impacted child and adolescent PA indicators in their country. RESULTS: Overall Physical Activity was the indicator with the lowest global average grade (D), while School and Community and Environment were the indicators with the highest global average grade (C+). An overview of the global situation in terms of surveillance and prevalence is provided for all 10 common PA indicators, followed by priorities and examples to support the development of strategies and policies internationally. CONCLUSIONS: The Global Matrix 4.0 represents the largest compilation of children's and adolescents' PA indicators to date. While variation in data sources informing the grades across countries was observed, this initiative highlighted low PA levels in children and adolescents globally. Measures to contain the COVID-19 pandemic, local/international conflicts, climate change, and economic change threaten to worsen this situation.

Association between Physical Literacy and Self-Perceived Fitness Level in Children and Adolescents.

BACKGROUND: Physical fitness is considered a predictor of mortality and comorbidities resulting from physical inactivity in children and adolescents. Physical literacy provides a robust and comprehensive assessment of physical fitness. Thus, it is considered a crucial element for understanding children and adolescents' health status and their physical activity-related behaviours. Moreover, the self-perceived fitness should also be considered. Therefore, this study aims to analyse the relationship between physical literacy and self-perceived physical fitness in children and adolescents aged 8-12 years. METHODS: A single-measure cross-sectional study was conducted with 135 children and adolescents. Anthropometric measurements and the Canadian Assessment of Physical Literacy Development (CAPL-2) were applied. Descriptive statistics and correlations were calculated. The Fitness Perception Scale for Adolescents (FP VAS A) scale was also administered to assess participants' self-perceived fitness. RESULTS: Moderate significant correlations were found between "physical competence", "motivation and confidence", and the total CAPL-2 score with FP VAS A. CONCLUSIONS: The influence of motivation on self-perceived fitness has been demonstrated. Moreover, cardiorespiratory fitness could be considered one of the most relevant and influential factors in the total CAPL-2 score. It means that higher levels of self-perceived fitness would be associated with greater levels of physical literacy.

Short-term branched-chain amino acid supplementation does not enhance vertical jump in professional volleyball players. A double-blind, controlled, randomized study.

INTRODUCTION: To the best of the authors' knowledge, no previous studies have described the effect of branched-chain amino acids (BCAA) on vertical performance during a week in professional volleyball players. This study assessed BCAA supplementation for a week, aiming to improve vertical jump performance in male professional volleyball players. Twelve male volleyballers were randomly assigned to a BCAA group (n = 6) or a control group (n = 6). The BCAA group ingested 21 g over a week, 7 g per day on Monday, Wednesday, and Friday, before a volleyball training session, while the control group drank a placebo drink. Participants performed 8 maximal countermovement jumps (CMJ); the 3 CMJs on Monday and Wednesday were evaluated after warm-up, after plyometric training, and at the end of the training session; and the 2 CMJs on Friday were evaluated after warm-up, and at the end of the training session. Compared with baseline, no significant differences in CMJ over the week were observed in BCAA or control group, neither between groups. The results indicated that 21 g of BCAA supplementation over a week did not improve vertical jump performance in professional volleyball players.

INTRODUCCIÓN: Hasta donde los autores saben, no se han descrito estudios previos sobre el efecto de los aminoácidos ramificados (BCAA) en el rendimiento vertical durante una semana en jugadores de voleibol profesionales. Este artículo estudió la suplementación de BCAA durante una semana con el objeto de mejorar el rendimiento del salto vertical en jugadores de voleibol profesionales masculinos. Doce jugadores de voleibol masculinos se asignaron aleatoriamente a un grupo con BCAA (n = 6) o a un grupo de control (n = 6). El grupo con BCAA ingirió 21 g en una semana, 7 g por día los lunes, miércoles y viernes antes de la sesión de entrenamiento de voleibol, mientras que el grupo de control bebió una bebida placebo. Los participantes realizaron 8 saltos máximos de contramovimiento (CMJ); los 3 CMJ de lunes y miércoles se evaluaron después del calentamiento y del entrenamiento pliométrico, y al final de la sesión de entrenamiento; los 2 CMJ del viernes se evaluaron después del calentamiento y al final de la sesión de entrenamiento. En comparación con el valor inicial, no se observaron diferencias significativas en los CMJ a lo largo de la semana, ni en el grupo BCAA ni en el grupo control, tampoco hubo diferencias entre grupos. Los resultados indicaron que 21 g de BCAA administrados durante una semana no mejoraron el rendimiento del salto vertical en jugadores de voleibol profesionales.