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Nicolas Vuillerme, Ludovic Marin and Bettina Debû

This study evaluated stance control in 24 teenagers with and without Down syndrome (DS) by (a) assessing center of foot pressure variables under different conditions of availability of visual and somatosensory inputs and (b) analyzing postural perturbation and adaptation following abrupt changes in visual information. Results showed no gender-related differences in either group. Group comparison revealed similar strategies in adolescents with and without DS, although quantitative differences may exist in the ability to integrate sensory inputs to control stance. Adaptation to changing environmental conditions varied greatly from one individual to another in the two groups. Finally, comparison of the two experiments suggests that the increased postural oscillations reported for the sample with DS on long lasting recordings could be related to insufficient allocation of cognitive resources in stable environments.

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Vatan Kavak

Our aim in this study was to determine the body fat percentage of teenagers in Diyarbakir, a city in southeast Turkey. The study included 1118 children between the ages of 10 to 15. Basic anthropometric measurements including body-mass index (BMI) and skinfold thickness were taken. The skinfold thickness were measured with a Lange skinfold caliper. Fat mass percentage (FM %) was predicted by using skinfold thickness equations. Differences between boys and girls across age groups for weight, height, and BMI were found to be statistically significant (P < 0.0001). With respect to skinfold thickness in the 10-y-old group, the thickness at triceps and subscapular sites in girls was higher than those of boys. In the 12-y-old group, the thickness was found to be higher in girls than boys at the triceps, biceps, and subscapular sites. We found that an increase in skinfold thickness in the 13, 14, and 15-y-old groups was significantly higher among girls than boys and tended to increase with age. However, such a tendency was not shown in boys. This tendency was found only at the triceps site in 10, 12, and 13-y-old boys. In addition, the skinfold thickness at the biceps site was found to be greater in the 14-y-old boys. The body fat mass percent in girls, especially those older than age 13, was also increased.

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Thomas J. Birk and Marianne Mossing

The purpose of this study was to determine whether heart rate and ventilation can be predicted from RPE. Also, this study determined whether breathing or heart rate sensations caused perceived effort or strain (degree of perceived central strain). Eight ambulatory active teenagers (ages 13-16 years, M= 14.75) with spastic cerebral palsy performed a discontinuous maximum bicycle ergometer protocol. Rate of perceived exertion (RPE), heart rate (HR) (V5 lead), and V̇E (Wright respirometer) were recorded each minute. Results indicated that Minutes 1 and 2 of Stage 1 were significantly correlated for RPE and ventilation, and RPE and heart rate were significantly correlated for Minutes 3 and 4 of Stages 1 and 2. Low standard error of estimates values were also evident for each of these minutes wherein significant correlations resulted. Initially, pulmonary strain was perceived as greater than HR for a given RPE value. However, by the conclusion of the second stage, breathing was slightly less than cardiac strain. Results suggest that RPE can be used to predict heart rate after the 2nd minute of discontinuous exercise training or testing. The accurate estimation of ventilation for the initial minutes of exercise may be limited since some anxiety, secondary to hyperventilation, could result. Also, breathing is perceived as a greater strain than heart rate initially but appears to equal and be slightly lower at the conclusion of aerobic exercise.

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Catherine B. Woods, Norah M. Nelson, Donal J. O’Gorman, Eimear Foley and Niall M. Moyna

Background:

The Take PART study—Physical Activity Research for Teenagers—was undertaken to assess (1) physical activity and sedentary behaviors, (2) indices of health and fitness, and (3) to provide information, from a social ecological perspective, on the correlates of physical activity in a large sample of 15- to 17-year-old Irish adolescents. This manuscript outlines the rationale and methodology of the Take PART study.

Methods:

A sample of 4720 students (mean age = 16.03 years ± 0.66, range 15 to 17 years; 49.5% female) participated. Fifty participants were assessed during each 3-hour school visit, with a ratio of 1 researcher to 10 students. Standardized testing procedures and extensive researcher training ensured that intertester and intratester reliability for all physical measures was ≥.85. The height, weight, waist circumference, hip circumference, blood pressure, and cardiorespiratory fitness protocols are explained. The questionnaire used well-known, valid, and reliable self-report measures. Where appropriate, additional psychometric testing was undertaken.

Conclusions:

Take PART is a school-based study. Its methods are simple, easy to replicate, financially viable, and scientifically valid. Its unique dataset will allow the evaluation of a social ecological approach as a viable option for improving understanding of youth inactivity. Ultimately, this knowledge will assist in successful intervention design.

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Maureen R. Weiss, Alan L. Smith and Marc Theeboom

The influence of peer groups on children’s psychosocial development is highlighted in the sport psychology literature in areas such as motivation, self-perceptions, and affect. However, scant research has been devoted to examining children’s and teenagers’ conceptions of friendships within the physical domain. Current and former sport program participants (N = 38) took part in an in-depth interview that concerned their best friend in sports. An inductive content analysis revealed the existence of 12 positive friendship dimensions: companionship, pleasant play/association, self-esteem enhancement, help and guidance, prosocial behavior, intimacy, loyalty, things in common, attractive personal qualities, emotional support, absence of conflicts, and conflict resolution. Four negative friendship dimensions were extracted: conflict, unattractive personal qualities, betrayal, and inaccessible. These conceptions of friendship were both similar and unique to friendship conceptions found in mainstream developmental research. Future research directions include measurement efforts, relationships among important constructs, and intervention techniques in the sport setting.

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Brian R. Hunt, James D. George, Pat R. Vehrs, A. Garth Fisher and Gilbert W. Fellingham

The purpose of this study was to validate the ability of the 1-mile jog test to predict VO2max in fit teenagers. Forty-one males and 42 females performed the steady-state, submaximal jogging test on an indoor track, along with a maximal graded exercise test (GXT) on a treadmill. Open circuit calorimetry was used during the GXT to measure maximal oxygen consumption (VO2max). We generated the following age-specific prediction equation applicable to boys and girls 13–17 years old (n = 83, Radj = .88, SEE = 3.26 ml · kg−1 · min−1): VO2max = 92.91 + 6.50 × gender (0 = female, 1 = male) − 0.141 × body mass (kg) − 1.562 × jog time (min) − 0.125 × heart rate (bpm). Cross-validation results were acceptable (SEEpress = 3.44 ml · kg−1 · min−1). As a field test, the submaximal 1-mile jogging test may alleviate problems associated with pacing, motivation, discouragement, injury, and fatigue that are sometimes associated with maximal effort timed or distance run tests.

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Alexandre Magalhães, Elisabete Ramos and Maria Fátima Pina

Background:

Proximity to urban green spaces (UGS) and open sports spaces (OSS) benefits health, promotes physical activity (PA) and sports practice (SP).

Objective:

Analyze the association between PA or SP according to distances between UGS or OSS and teenagers’ residences or schools.

Methods:

We evaluated 1333 (53.9% girls) teenagers (13 years old) living and studying in Porto, Portugal (EPITeen cohort). PA was classified as light or moderate/vigorous. Distances were the shortest routes from residences or schools to UGS/OSS, and classified in ≤250 m; >250 m to ≤500 m; >500 m to ≤750 m; >750 m. Chi-square test and chi-square for trends were used to compare proportions; associations were measured using logistic regression, through odds ratio and 95% confidence intervals, adjusting to BMI and parental education.

Results:

Regarding vicinity’ of schools, the prevalence of moderate/vigorous PA among boys, decreases as distances to OSS increases. For girls, the prevalence of sports decreases as distances to UGS increase. For boys, we found an association between moderate/vigorous PA and proximity to OSS in the vicinity of schools: considering ≤250 m as reference, the odds of moderate/vigorous PA is 0.20 (0.06–0.63) for >250 m to ≤500 m; 0.21 (0.07–0.61) for >500 m to ≤750 m and 0.19 (0.06–0.58) for >750 m.

Conclusion:

Vicinities of schools seem to influence teenagers to be more physically active and increase sports participation.

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Tina Louisa Cook, Ilse De Bourdeaudhuij, Lea Maes, Leen Haerens, Evangelia Grammatikaki, Kurt Widhalm, Lydia Kwak, Maria Plada, Luis Alberto Moreno, Yannis Tountas, Antonis Zampelas, Yannis Manios and on hehalf of the HELENA group

Background:

The aim was to examine if psychosocial determinants (attitudes, self-efficacy, social support from a sports partner) and perceived environmental barriers (PEB) of physical activity (PA) mediated the effect of a 3-month Internet-based intervention on PA in European adolescents.

Methods:

A sample of 536 adolescents (51% boys) aged 12–17 years were randomly assigned to intervention or control condition. Questionnaires were used to assess different PA behaviors, psychosocial determinants and PEB at baseline and at 3-month follow-up. Mediating effects were assessed with the bootstrapping method.

Results:

PEB regarding neighborhood safety mediated the effect of the intervention on all PA indices. PEB regarding sports facilities availability at neighborhood and PEB regarding sport-related facilities availability at school mediated the effect of the intervention on moderate to vigorous PA (MVPA) and moderate PA (in leisure time and at school, respectively). Social support from a sports partner suppressed the effect of the intervention on vigorous PA and MVPA. No other factor had a mediation effect.

Conclusions:

All PEB measures appear to mediate PA behaviors of different intensities and in different contexts. Interventions promoting PA in adolescents should also focus on improving the targeted PEB as mediators of engagement in PA to bring the desired effects in actual behaviors.

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Thiago R.S. Tenório, P. Babu Balagopal, Lars B. Andersen, Raphael M. Ritti-Dias, James O. Hill, Mara C. Lofrano-Prado and Wagner L. Prado

Purpose: To investigate the effects of a low- versus high-intensity aerobic training on biomarkers of inflammation and endothelial dysfunction in adolescents with obesity. Methods: Sixty-two adolescents with obesity [age = 15 (14) y, body mass index = 34.87 (4.22) kg·m−2] were randomized to receive either a high-intensity training (HIT, n = 31) or a low-intensity training (LIT, n = 31) for 24 weeks. All participants also received nutritional, psychological, and clinical counseling. Leptin, total and subtype leukocyte counts, tumor necrosis factor-alpha, interleukin-6, myeloperoxidase, soluble intercellular adhesion molecule-1, and soluble vascular cell adhesion molecule-1 were obtained at baseline and after 24 weeks. Results: HIT reduced neutrophils [from 4.4 (1.9) to 3.6 (1.3) µL−1 × 103; P = .01] and monocytes [from 7.2 (2.5) to 5.2 (1.8) µL−1 × 102; P < .01], but LIT increased neutrophils [from 4.5 (1.7) to 5.2 (3.3) µL−1 × 103; P = .01]. Although tumor necrosis factor-alpha increased in LIT [from 13.3 (7.5) to 17.7 (10.8) pg·mL−1; P = .01], it decreased in HIT [from 12.4 (7.5) to 11.3 (6.2) pg·mL−1; P = .01]. No changes in leukocyte counts, soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, and homeostasis assessment model for insulin resistance were observed. Conclusions: Both HIT and LIT improved the inflammatory profile. The study, however, indicated that the number of biomarkers and the magnitude of changes were higher in the HIT compared with LIT.

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Yi-Ju Tsai, Chieh-Chie Chia, Pei-Yun Lee, Li-Chuan Lin and Yi-Liang Kuo

Context: Core control and strength are important for reducing the risk of lower-extremity injury. Current evidence on the effect of core training in male adolescent athletes is limited, and other investigations into the effects of core training often emphasized core strength only. Objective: To examine whether core training emphasizing both control and strength of the trunk and hip would improve joint kinematics during landing, sports performance, and lower-extremity muscle strength in adolescent male volleyball athletes. Design: Single group pretest and posttest design. Setting: University laboratory. Participants: Sixteen male participants (age: 13.4 [1] y, height: 167.8 [8.6] cm, mass: 58.6 [13.9] kg, and volleyball experience: 3.8 [1.5] y) from a Division I volleyball team at a junior high school. Main Outcome Measurements: Kinematics of the trunk and lower-extremity during box landing and spike jump landing tasks, volleyball-related sports performance, and isokinetic strength of hip and knee muscles were assessed before and after a 6-week core training program. Results: After training, the participants demonstrated decreased trunk flexion angle (P = .01, Cohen’s d = 0.78) during the box landing task and reduced the maximum knee internal rotation angle (P = .04, Cohen’s d = 0.56) during the spike jump landing task. The average isokinetic strength of hip flexors and external rotators, and knee flexors and extensors also significantly increased (P = .001, Cohen’s d = 0.98; P = .04, Cohen’s d = 0.57; P = .02, Cohen’s d = 0.66; P = .003, Cohen’s d = 0.87, respectively); however, sports performance did not show significant changes. Conclusions: A more erect landing posture following training suggests that the core training program may be beneficial for improving core stability. The long-term effect of core training for knee injury prevention needs further investigation.