Secular trends in 20 m shuttle run test performance of 14- to 15-year-old adolescents from 1995 to 2020

PURPOSE

To investigate whether Finnish adolescents' cardiorespiratory fitness measured using the 20 m shuttle run test (20mSRT) changed between 1995 and 2020 and to examine between-group variation in the five datasets during the past 25 years.

METHODS

Data on five cohorts were collected in 1995 (n = 498), 1998 (n = 796), 2003 (n = 2383), 2010 (n = 1383), and 2020 (n = 719). The 20mSRT was administered, following the exact same protocol, to all cohorts. A general linear contrast model was used to examine cohort differences in the 20mSRT scores. Variation across cohorts was tested using chi-square-based between-group tests.

RESULTS

Girls' 20mSRT scores decreased from 1995 to 2010 and remained stable from 2010 to 2020. Boys' 20mSRT scores decreased continuously from 1995 to 2020. In addition, the variation in girls' 20mSRT scores was larger in the 2020 than 2003 cohort, indicating the growth of SRT differences between individuals in 2020 cohort compared to 2003 cohort. Similarly, boys' scores showed greater variation, especially in the 2010 and 2020 cohorts than in the 1998 cohort.

CONCLUSION

The results of this study showed an overall decline in the cardiorespiratory fitness performance measured by 20mSRT of Finnish adolescents. Boys' scores decreased continuously from 1995 to 2020, whereas girls' scores remained stable after 2010. Examination of the variation in scores further revealed that the gap in scores between the adolescents with the highest and lowest scores increased over time.

Exercise and Cardiovascular Disease Risk Factors in Children and Adolescents With Obesity: A Systematic Review With Meta-Analysis of Randomized Controlled Trials

The purpose of this study was to examine the effects of exercise on cardiovascular disease (CVD) risk factors in children and adolescents with obesity. Randomized controlled trials (RCTs) of exercise ≥4 weeks in children and adolescents with obesity were included if one or more CVD risk factors were included as an outcome. Studies were retrieved by searching 7 electronic databases, cross-referencing, and expert review. Data were pooled using the inverse-variance heterogeneity (IVhet) model and strength of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) instrument. Thirty-nine studies representing 1548 participants (847 exercise, 701 control) met the inclusion criteria. Aerobic exercise improved 10 of 12 (83.3%) outcomes (P < .05 for all) while combined aerobic and strength training improved 5 of 8 (62.5%) outcomes (P < .05 for all). The strength of evidence ranged from "very low" to "moderate." It was concluded that aerobic exercise, as well as combined aerobic and strength training, is associated with improvements in multiple CVD risk factors among children and adolescents with obesity. However, the generally low strength of evidence suggests a need for future well-designed and conducted RCTs on the effects of exercise, especially strength training, in children and adolescents with obesity.

Nutrition Curriculum Training and Implementation Improves Teachers' Self-Efficacy, Knowledge, and Outcome Expectations

OBJECTIVE

To examine the effects of training and implementation of Forecasting Your Future: Nutrition Matters on teachers' self-efficacy to teach nutrition and teachers' nutrition knowledge and explore outcome expectations for students.

METHODS

A mixed-methods study, with Indiana Family and Consumer Sciences high school teachers randomized to control and intervention, was conducted using baseline surveys, implementation of new or usual curriculum, follow-up survey(s), and semistructured interviews. Self-efficacy and knowledge were analyzed by hierarchical linear modeling. Interviews were thematically analyzed using a 5-phase process to identify outcome expectations.

RESULTS

Intervention teachers (n = 17) had greater increases in nutrition knowledge (P = 0.028) and self-efficacy (P = 0.010) compared with controls (n = 18). Interviews revealed that teachers sought to affect students' long-term health by providing knowledge and skills to make healthy choices.

CONCLUSIONS AND IMPLICATIONS

This training with updated curricula and implementation improved theoretical determinants of effective nutrition instruction. Teachers expected student learning will contribute to future eating behaviors.

Forecasting Your Future: Nutrition Matters Curriculum with Teacher Training Promotes Students to Try New Fruits and Vegetables

BACKGROUND

Many high school students do not consume the recommended amounts of fruits and vegetables.

OBJECTIVE

This study evaluated student outcomes from a new nutrition curriculum that includes messages from the 2015-2020 Dietary Guidelines for Americans with a teacher training component for high school Family and Consumer Sciences (FACS) teachers.

METHODS

A cluster-randomized controlled study was conducted with 1104 students in FACS classes from 35 schools, taught by teachers trained in implementing a new curriculum (intervention) and teachers using their usual curricula (control). Students completed online surveys at the beginning and end of the semester, that is, pre- and postexposure to the nutrition curricula. Intention-to-treat analyses as hierarchical linear modeling were performed to determine if the intervention students had significant changes compared with the control students for knowledge of nutrition concepts, familiarity of, preferences for, affinity toward, number of times trying new, and daily times eating fruits and vegetables. Per-protocol analyses used the same hierarchical linear model but instead of control and intervention groups, students were split into 3 levels describing the amount of the new curriculum they received (0%, 1-50%, and 51-100%).

RESULTS

Students exposed to 51-100% of the new curriculum tried more fruits and vegetables than both the control students and the students that received 1-50% of the curriculum (P = 0.009 for fruits and P = 0.002 for vegetables). Additionally, there were higher increases in the number of times intervention students tried a new fruit (P = 0.027) and vegetable (P = 0.022) compared with the control students, regardless of the amount of curriculum received.

CONCLUSIONS

Our findings show that the curriculum, Forecasting Your Future: Nutrition Matters, has promise for increasing exposure to new fruits and vegetables for students. If teachers use most of the curriculum, students are likely to try more new fruit and vegetables, which could ultimately contribute to improved health.