Influence of Activity Patterns in Fitness During Youth

Physical fitness and somatic structure in adolescent taekwondo athletes and untrained peers

Study aim: The purpose of the study was to assess the level of physical fitness (PF) and somatic structure in children training a Korean martial art (ITF taekwondo) and untrained peers and to determine the associations of children’s BMI with that of their parents.

Material and methods: The research material consisted of data from 135 individuals, representing 45 child-mother-father triplets, including 22 triplets with children practicing taekwondo and 23 triplets with untrained children. The children had an average chronological age of 10.08 ± 1.35 years, whereas the age of mothers and fathers was 38.09 ± 4.56 years and 40.57 ± 4.70 years, respectively. Traits analyzed included those evaluated by selected physical fitness tests from the Eurofit Physical Fitness Test battery, body mass index (BMI), and waist-to-height ratio (WHtR) in children, and BMI in parents. Statistical analyses included the chi-square test, Mann-Whitney U test, and Spearman’s correlations, with a significance level set at α = 0.05.

Results: The results showed no significant differences in the somatic structure, physical fitness, BMI, and WHtR in the children studied. However, a tendency was observed for children attending ITF taekwondo classes to be characterized by higher levels of physical fitness. Higher BMI was found in the parents of the trained children and positive correlations were found between the BMI of the trained children and their parents.

Conclusions: Identifying and studying the effect size of PA determinants in adolescents, with a particular focus on the influence of parents, may be the key to improving the health of future generations.

Impact of physical activity on redox status and nitric oxide bioavailability in nonoverweight and overweight/obese prepubertal children

Nutritional status might contribute to variations induced by physical activity (PA) in redox status biomarkers. We investigated the influence of PA on redox status and nitric oxide (NO) production/metabolism biomarkers in nonoverweight and overweight/obese prepubertal children. We performed a cross-sectional evaluation of 313 children aged 8-9 years (163 nonoverweight, 150 overweight/obese) followed since birth in a cohort study (Generation XXI, Porto, Portugal). Plasma total antioxidant status (P-TAS), plasma and urinary isoprostanes (P-Isop, U-Isop), urinary hydrogen peroxide (U-H₂O₂), myeloperoxidase (MPO) and plasma and urinary nitrates and nitrites (P-NOx, U-NOx) were assessed, as well as their association with variables of reported PA quantification (categories of PA frequency (>1x/week and ≤1x/week)and continuous PA index (obtained by the sum of points)) in a questionnaire with increasing ranks from sedentary to vigorous activity levels. U-NOx was significantly higher in children who presented higher PA index scores and higher PA frequency. Separately by BMI classes, U-NOx was significantly higher only in nonoverweight children who practiced PA more frequently (p = 0.037). In overweight/obese children, but not in nonoverweight, P-TAS was higher among children with higher PA frequency (p = 0.007). Homeostasis model assessment index (HOMA-IR) was significantly lower in more active overweight/obese children, but no differences were observed in nonoverweight children. In the fully adjusted multivariate linear regression models for P-TAS, in the overweight/obese group, children with higher PA frequency presented higher P-TAS. In the U-NOx models, U-NOx significantly increased with PA index, only in nonoverweight children. Our results provide additional evidence in support of a protective effect of physical activity, in nonoverweight by increasing NO bioavailability and in overweight/obese children by enhancing systemic antioxidant capacity and insulin sensitivity. These results highlight the importance of engaging in regular physical exercise, particularly among overweight/obese children, in which a positive association between oxidant status and cardiometabolic risk markers has been described.

Cardiorespiratory Fitness Is Associated With Drop Out From Sport in Norwegian Adolescents. A Longitudinal Study

Several studies indicate that participation in organized sport may result in higher physical activity levels among youth which are associated with high levels of cardiorespiratory fitness. However, no study has examined whether cardiorespiratory fitness (VO2peak) is associated with drop out from sport. The study was a 5-year longitudinal study which followed a sample of adolescents, with measures of cardiorespiratory fitness, weight and height between the age of 14 and 19 yrs. Self-reported data about participation in sport, active commuting and physical activity level were also included. Through logistic regression analyses we found a positive association between cardiorespiratory fitness at the age of 14 years and participation in organized sport at the age of 19. However, no significant associations were found between physical activity (PA) level, overweight, gender and active commuting to school at the age of 14, and participation in organized sport at the age of 19. We argue that a high level of cardiorespiratory fitness may increase the probability for experiencing high levels of enjoyment, competence and performance in sport, because sport participation requires a certain level of cardiorespiratory fitness. The findings indicates the importance of removing barriers, and to increase access and design of sport programs of interest to youth in the contexts in which they live, attract adolescents with different levels of ambition and abilities in sport. Further studies should include longitudinal studies among young children, and their drop out patterns from sport during adolescence.

Associations of Participation in Organized Sport and Self-Organized Physical Activity in Relation to Physical Activity Level Among Adolescents

Although physical activity level (PAL) is positively correlated with adolescents' health, many adolescents do not fulfill recommendations for physical activity. This study examines the associations of organized sport and self-organized physical activity, with PAL among adolescents. Participants were 301 adolescents (12-13 year-olds). The adolescents wore accelerometers for 1 week according to international standards, and reported their participation in organized sport and self-organized physical activity in a questionnaire. The results showed that the level of participation in organized sport was positively associated with the adolescents' total PAL, while there was no significant association between time spent in self-organized physical activity and adolescents' daily minutes of moderate and vigorous physical activity. In addition, boys who participated <3 h per week (or not at all) in organized sport stood out with the lowest fulfillment of recommended PAL. Our findings underline the critical importance of getting adolescents, especially boys, to participate in organized sport and not to drop out from organized sport during adolescence.

Organized Sports and Physical Activities as Sole Influencers of Fitness: The Homeschool Population

Homeschool children may rely solely on organized sports and physical activities to achieve recommended levels of physical activity and fitness. The purpose of this study was to investigate differences in fitness levels between homeschool children who did, and did not, participate in organized sports or physical activities, and then examine relationships between hours per week in sports or physical activities and cardiorespiratory fitness as measured by portions of the FitnessGram^® test battery. Organized sports/physical activity participation information was gathered on 100 children ages 10-17 years who completed tests of upper, abdominal, and cardiorespiratory fitness. The current investigation revealed that participation alone was not associated with higher levels of physical fitness as assessed by the 90° push-up test or curl-up test nor was time in participation related to cardiorespiratory fitness as assessed by the Progressive Aerobic Capacity Endurance Run (PACER). These activities alone may be insufficient for meeting physical activity recommendations and improving physical fitness. Therefore, children and adolescents educated at home may need additional opportunities to participate in unstructured daily physical activity.

The Importance of Adolescents' Participation in Organized Sport According to VO2peak: A Longitudinal Study

Research from several countries has documented a decline in physical activity (PA) levels and in participation in organized sport with increasing age, indicating that organized sport may be of importance to adolescents' cardiorespiratory fitness (CRF).

PURPOSE

The purpose of this study was to examine how regular participation in organized and unorganized PA affected the development of adolescents' CRF (peak oxygen consumption [VO₂peak]), when controlled for sex interaction.

METHOD

Data on direct measures of VO₂peak and participation in organized PA among adolescents organized into 3 groups (participation in organized sport, participation in unorganized PA, and no weekly PA) were collected from 76 students (39 boys and 37 girls), when they were aged 14 and 19 years old.

RESULTS

Statistically significant differences were found between VO₂peak values in the 3 groups at both 14 years of age, F(2, 73) = 7.16, p < .05, ƞ² = .170, and 19 years of age, F(2, 73) = 14.00, p < .05, ƞ² = .300, independent of sex at both 14 and 19 years of age, F(2, 73) = 0.05, p > .05, ƞ² = .02, and F(2, 73) = 0.05, p > .05, ƞ² = .00. Adolescents participating in organized sport also had statistically significantly higher VO₂peak values than adolescents participating in unorganized PA and those with no weekly PA, at both 14  and 19 years of age.

CONCLUSION

From a health perspective, in terms of CRF, the findings highlight the importance of encouraging adolescents to participate in organized sport and to refrain from dropping out of organized sport programs.

Associations between a posteriori defined dietary patterns and bone mineral density in adolescents

PURPOSE

Dietary pattern analysis may uncover the joint effects of multiple dietary components on bone health, but such research is scarce and targets mostly adults.

METHODS

We quantified prospective associations between dietary patterns and bone mineral density (BMD) in 1,007 adolescents of a cohort born in 1990 and recruited at schools in Porto during the 2003/2004 school year. Forearm BMD was measured using dual-energy X-ray absorptiometry. Participants' dietary patterns were classified "Healthier", "Dairy products", "Fast food and sweets" and "Lower intake" according to previously identified patterns obtained in a larger sample of 1,489 participants using the K-means method. Using dietary patterns at 13 years old as the main exposure, associations were estimated cross-sectionally (with BMD at the age of 13) and prospectively (with annual BMD variation between 13 and 17 years), using linear regression coefficients adjusted for height, weight, energy intake and, in girls, for menarche age.

RESULTS

No significant associations between the a posteriori dietary patterns identified and mean BMD at 13 were found. However, among girls, adherence to a pattern characterized by low intake of energy and all food groups was negatively associated with annual BMD variation between 13 and 17 years [adjusted coefficient (95 % CI) -0.451 (-0.827; -0.074) mg·cm⁻²·year⁻¹].

CONCLUSIONS

Although results showed that, in girls, adherence to a "Lower intake" dietary pattern is associated with lower annual BMD variation throughout adolescence, overall, there were no consistent associations between dietary patterns and forearm BMD in adolescents.

The association between cardiovascular disease risk and parental educational level in Portuguese children

The aim of this study was to examine any differences in cardiovascular disease (CVD) risk in Portuguese children split by parental educational level. A cross-sectional school-based study was conducted in 2011 on 359 Portuguese children (202 girls and 157 boys) aged 10 to 17 years (mean age ± SD = 13.9 ± 1.98 years). Height and body mass were assessed to determine body mass index (BMI). Parental education level (PEL) was used as a surrogate for socioeconomic status (SES). Capillary blood sampling was used to determine: Total Cholesterol (TC), Triglycerides (TG), Fasting Glucos (GLUC), High and Low Density Lipoprotein (HDL/LDL). These measurements were combined with measures of systolic blood pressure and cardiorespiratory fitness as z-scores. CVD risk was constructed by summing the z-scores. Analysis of covariance, controlling for BMI, indicated that CVD risk was significantly different across PEL groups (p = 0.01), with CVD risk score being significantly lower in low (p = 0.04) and middle (p = 0.008) PEL groups, compared to high PEL. Moreover, the covariate, BMI was also significant (p = 0.0001, β = 0.023), evidencing a significant positive association between BMI and CVD risk, with higher BMI associated with greater CVD risk. In Portuguese children, significantly greater CVD risk was found for children of high PEL, while higher BMI was associated with greater CVD risk.