Associations between Spanish children's physical activity and physical fitness with lean body mass: The CALINA study

Research on the relationship between physical literacy and demographic variables and interpersonal support for physical exercise among adolescents in China

In recent decades, the concept of "Physical Literacy" has emerged as a significant breakthrough in enhancing the physical health of children and adolescents. This concept has become the guiding principle and future direction for physical education reform in Western countries. As China's economic and social development enters a new phase, the negative impact of insufficient physical activity on adolescent health remains a significant challenge to the strategies of "Healthy China" and "A Leading Sports Nation." The unique value of physical literacy, which emphasizes the importance of regular physical activity, aligns perfectly with the developmental needs of the nation, the era, and individuals. Given the crucial role of interpersonal support in the development of adolescents' physical literacy, this study employs questionnaire surveys and statistical analysis to investigate the current state of physical literacy among Chinese adolescents. It explores the predictive relationship between parental support, teacher support, and peer support on physical literacy, aiming to provide guidance for the future development of adolescents' physical literacy. The research findings indicate significant differences in the five dimensions of physical literacy (attitude, sports knowledge, emotion, athletic ability, and physical fitness) among adolescents of different grades and residence type. Additionally, there are notable gender differences in the dimensions of sports knowledge, emotion, and athletic ability. The interaction effect of gender and grade is particularly evident in the emotional and physical fitness dimensions. There is a significant correlation between interpersonal support and all dimensions of physical literacy. After controlling for variables such as gender, grade, and family background, interpersonal support for adolescent physical exercise was found to have a significant impact on all dimensions of physical literacy. Among the forms of support, peer support was identified as a more powerful predictor of physical literacy compared to parental and teacher support.

Cross-sectional and longitudinal associations between the 24-hour movement behaviours, including muscle and bone strengthening activity, with bone and lean mass from childhood to adolescence

BACKGROUND

This study aimed to assess whether moderate-to-vigorous physical activity (MVPA), sport and exercise as a proxy measure of muscle and bone strengthening activity, sedentary behaviour, and sleep were associated with total-body-less-head (TBLH) bone mineral content (BMC) and TBLH lean mass cross-sectionally and longitudinally from age 6 to 9 years and age 9 to 11 years to age 15 to 17 years.

METHODS

We used longitudinal data from a population sample of Finnish children from the Physical Activity and Nutrition in Children study (age 6 to 9 years: n = 478, 229 females; age 9 to 11 years: n = 384, 197 females; age 15 to 17 years: n = 222, 103 females). Linear regression analysed the cross-sectional and longitudinal associations between accelerometer-assessed MVPA, sedentary time and sleep, and questionnaire-assessed sport and exercise participation and screen time with dual-energy X-ray absorptiometry-assessed TBLH BMC and lean mass.

RESULTS

In females, MVPA at age 6 to 9 years was positively associated with TBLH BMC at age 15 to 17 years (β = 0.008, p = 0.010). Sport and exercise at age 9 to 11 years was positively associated with TBLH BMC (β = 0.020, p = 0.002) and lean mass (β = 0.343, p = 0.040) at age 15 to 17 years. MVPA at age 9 to 11 years was positively associated with TBLH lean mass (β = 0.272, p = 0.004) at age 15 to 17 years. In males, sleep at age 6 to 9 years was positively associated with TBLH lean mass (β = 0.382, p = 0.003) at age 15 to 17 years. Sport and exercise at age 9 to 11 years was positively associated with TBLH BMC (β = 0.027, p = 0.012) and lean mass (β = 0.721, p < 0.001) at age 15 to 17 years.

CONCLUSIONS

Promoting engagement in the 24-hour movement behaviours in childhood, particularly sport and exercise to strengthen muscle and bone, is important in supporting bone and lean mass development in adolescence.

TRIAL REGISTRATION

NCT01803776; first trial registration date: 04/03/2013.