The Efficacy of Brief School-Based Exercise Programs in Improving Pubertal Bone Mass and Physical Fitness: A Randomized Controlled Trial

School-based physical activity interventions: which intervention characteristics are associated with participation and retention? A meta-analysis

OBJECTIVE

Many school-based intervention studies are conducted to increase students' physical activity (PA). Recruitment and retention problems potentially impact the robustness of RCT findings. We conducted a meta-analysis to summarize recruitment and retention rates in long-term secondary school-based PA intervention studies and examined associated participant and intervention characteristics.

METHODS

Web of Science, Pubmed, Medline, and PsychInfo were searched until March 20th 2023. We included studies on secondary school-based PA interventions ≥12 weeks, aimed at typically developing adolescents. We abstracted number of schools and students invited, randomized, and participating at follow-up to calculate pooled recruitment and retention rates; participant and intervention characteristics were abstracted to execute subgroup or meta-regression analyses.

RESULTS

Recruitment rates were 51% for invited schools and 80% for invited students, the retention for schools was almost 100% and for students 91%. Interventions with fixed and flexible components, executed in Asia and South America, and from later publication years had higher student recruitment rates. Students' retention rates were lower for interventions which had flexible components, were theory/model-based, used an accelerometer, had a longer intervention duration, and included more females.

CONCLUSION

Recruitment and retention rates in school-based PA interventions are high. Some participant and intervention characteristics influence these rates: flexibility of the intervention, theory/model-based intervention, accelerometer use, intervention duration, continent, and number of females. Researchers should consider these characteristics in intervention development to achieve optimal balance between intervention effectiveness, recruitment, and retention.

Process evaluation of school-based high-intensity interval training interventions for children and adolescents: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Several systematic reviews have been published to investigate the effectiveness of high-intensity interval training (HIIT) in schools. However, there has been limited attention given to understanding the functioning of the intervention processes, which is of paramount importance for interpreting and translating the intervention effectiveness. The aim of this systematic review is to determine the extent to which process evaluation is measured in school-based HIIT interventions and to explore the effects of process evaluation and intervention characteristics on cardiorespiratory fitness (CRF), body composition, muscular strength, and blood pressure.

METHODS

A comprehensive search was conducted in SPORT Discus (EBSCOhost), Web of Science, Scopus, Medline (Ovid) and Cochrane Central Register of Controlled Trials. The extent to which process evaluation is measured was narratively reported, alongside with the guidance of process evaluation of complex interventions by UK Medical Research Council. Meta-analyses and meta-regressions were conducted to determine the effects of process evaluation and intervention characteristics to the intervention outcomes.

RESULTS

The literature search identified 77 studies reporting on 45 school-based HIIT interventions. In total, five interventions reported process evaluation in a section or in a separate study, and only one intervention adopted a process evaluation framework. On average, 6 out of 12 process evaluation measures were reported in all interventions. Subgroup analyses did not indicate any beneficial treatment effects for studies with process evaluation group, whereas all pooled data and studies without process evaluation group showed significant improvement for CRF and body composition.

CONCLUSION

Process evaluation is frequently omitted in the literature of school-based HIIT in children and adolescents. Although reporting of process evaluation measures may not directly associate with better intervention outcomes, it allows accurate interpretation of intervention outcomes, thereby enhancing the generalisability and dissemination of the interventions.

Physical Fitness and Dietary Intake Improve Mental Health in Chinese Adolescence Aged 12-13

Background

Mental health has become a major public health issue worldwide. Biological and epidemiological studies have suggested that diet and physical fitness play a role in the prevention or cure of mental disorders. However, further research is required to elucidate the relationship between diet, physical fitness, and mental health. The study aims to provide a theoretical basis for promoting an adolescent healthy lifestyle and preventing mental problems by exploring the relationship between physical fitness, calcium intake, calorie intake, and adolescent mental health.

Methods

A cross-sectional study of a sample of adolescents (N = 253, 12-13 years) was conducted. The study involved adolescents from three middle schools in Central Jiangsu Province, including 136 boys and 117 girls. Weight, height, and body mass index were measured. Physical fitness was scored using the Chinese National Student Physical Fitness Standard. Diet data were collected using a weighed 7-day food diary to estimate energy intake and dietary calcium intake. The mental health status of the participants was assessed using the Chinese Middle School Student Mental Health Scale. A T-test and analysis of variance were used to analyze the differences of variables between different genders and body mass index, and Pearson correlation and stepwise multiple regression were used to explore the relationship between physical fitness, dietary intake, and mental health.

Results

The height (165.13 ± 8.07), weight (55.24 ± 13.00), and strength quality (64.93 ± 21.66) of boys are higher than those of girls (161.67 ± 6.44,48.99 ± 8.97, 58.40 ± 23.75, P < 0.05), and the flexibility quality (74.59 ± 14.75) of girls is higher than that of boys (68.30 ± 20.84) (P < 0.05). There were significant differences in the total scores of speed and physical fitness (F values were 4.02187.73, 3.07, 5.95, 10.33, and 9.52, respectively, P < 0.05). There was a significant positive correlation between calcium intake, cardiopulmonary fitness, and mental health (r = 0.276, P < 0.01; r = 0.159, P < 0.05). Calcium intake and cardiopulmonary fitness could explain 8.4% of the changes in the mental health of adolescents aged 12-13(ΔR2 = 0.084, P < 0.05).

Conclusion

Adequate calcium intake and the improvement of cardiopulmonary fitness in adolescents aged 12-13 are essential for the good development of their mental health. Future research in this field should examine the prospective associations between multiple measures of physical fitness composition and other nutrients ingested and mental health outcomes, as well as intervention studies that seek to provide evidence of causality.