bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors Contributing to the Energy Expenditure of Youth during Cycling and Running
Authors: McMurray Robert G. , Harrell Joanne S. , Bangdiwala Shrikant I. , Deng Shibing , Baggett Chris
Published: August 2016

This study evaluated factors that contribute to the increased energy cost of locomotion in youth. The subjects were 321 8-18-year-old youth, similar dispersed by age and sex. Oxygen uptake (VO2) was measured during rest (REE), running at 8 km · h−1 and cycling at 16 km · h−1, using a COSMED K4b2 metabolic system. Developmental stage was obtained via questionnaire. Stature, body mass, and skinfolds (triceps & subscapular) were measured. Both sexes had similar absolute VO2 (mL · min−1) at rest (p = 0.065) and running (p = 0.084), but the males had a higher VO2 during cycling (p = 0.046). There were no sex differences in relative VO2 (mL · kg−1 · min−1) at rest (p = 0.083); however, the males had a higher VO2 than the females during cycling and running (p £ 0.002). Multiple regression, tested for collinearity, found that absolute VO2 during cycling and running was mostly related to fat-free mass (p = 0.0001). Similar analyses for relative VO2 (mL · kg−1 · min−1) during cycling found that fat-free mass, sex, and skinfolds were significant contributors (p ‡ 0.003). During running the relative VO2 was related to skinfolds, fat-free mass, and resting energy expenditure (p < 0.05). Neither age nor developmental stage was a significant contributor. The results indicate that the VO2 of locomotion is most closely associated with fat-free mass. Thus, to compare youth of varying age or pubertal developmental status, fat-free mass should be taken into consideration.
Exercise and Resting Blood Pressure in Children and Adolescents: A Meta-Analysis
Authors: Kelley George A. , Kelley Kristi S.
Published: August 2016

The purpose of this study was to use the meta-analytic approach to examine the effects of exercise on resting systolic and diastolic blood pressure in children and adolescents. Twenty-five studies that included 84 groups (45 exercise, 39 control) and 3,189 subjects (1,885 exercise, 1,304 control) met the criteria for inclusion. Using a random effects model, non-significant decreases of approximately 2% were found for resting systolic (mean – SEM, –2 – 1 mmHg, 95% CI, –4 to 1 mmHg) and diastolic (mean – SEM, –1 – 1 mmHg, 95% CI, –3 to 1 mmHg) blood pressure. Greater decreases in resting systolic blood pressure were found for nonrandomized versus randomized controlled trials (p = 0.001). There was also a statistically significant association between changes in resting systolic blood pressure and initial blood pressure (r = 0.73, p < 0.001) and body weight (r = 0.64, p < 0.001). However, when limited to randomized trials, these results were no longer statistically significant. The results of this study suggest that exercise does not reduce resting systolic and diastolic blood pressure in children and adolescents. However, a need exists for additional randomized controlled trials, especially among hypertensive children and adolescents.
A Longitudinal Study of Children’s Enjoyment of Physical Education
Authors: Prochaska Judith J. , Sallis James F. , Slymen Donald J. , McKenzie Thomas L.
Published: August 2016

One mission of physical education (PE) is the promotion of enjoyable physical activity participation. PE enjoyment of 414 elementary school students (51% male, 77% Caucasian) was examined in a 3-year prospective study. Analyzed using Generalized Estimating Equations, PE enjoyment decreased significantly from the fourth to sixth grade (p < .001) and was lower among girls (p < .001) and students not in organized sports (p < .005). Ethnicity and body mass index were not significant predictors of PE enjoyment. Girls, older children, and those not on sports teams are especially dependent on PE as the setting for accruing health-related physical activity, and strategies are needed to enhance their PE enjoyment.
Measuring Physical Activity in Children: A Comparison of Four Different Methods
Authors: O’Connor Janice , Ball Elizabeth J. , Steinbeck Kate S. , Davies Peter S.W. , Wishart Connie , Gaskin Kevin J. , Baur Louise A.
Published: August 2016

The aim of this study of 56 children aged 6-9 years was to identify measures of physical activity that could be used in either clinical or population studies. Comparisons were made between four measures of physical activity: a three day parent-reported activity diary, a parent-reported physical activity questionnaire, the Tritrac-R3D™ accelerometer (worn three days) and physical activity energy expenditure calculated over 10 days by the doubly labeled water (DLW) technique. The strongest correlation between methods was for the diary and Tritrac-R3D™ during the two hour after-school period (1530-1730 hours) (r = 0.75, P < 0.0001). Activity level in this after-school period was positively correlated with average activity level over three days for both Tritrac-R3D™ (r = 0.53, P < 0.01) and diary (r = 0.54, P < 0.0001). No associations were found between measures of activity from DLW and activity measures from the Tritrac-R3D™, diary or questionnaire. These results suggest that the two hour after-school period is of high interest for future population studies of physical activity in school-age children.
Validation of a 3-Day Physical Activity Recall Instrument in Female Youth
Authors: Pate Russell R. , Ross Rebecca , Dowda Marsha , Trost Stewart G. , Sirard John R.
Published: August 2016

The purpose of this study was to examine the validity of the 3-Day Physical Activity Recall (3DPAR) self-report instrument in a sample of eighth and ninth grade girls (n = 70, 54.3% white, 37.1% African American). Criterion measures of physical activity were derived using the CSA 7164 accelerometer. Participants wore a CSA monitor for 7 consecutive days and completed the self-report physical activity recall for the last 3 of those days. Self-reported total METs, 30-min blocks of MVPA, and 30-min blocks of VPA were all significantly correlated with analogous CSA variables for 7 days (r = 0.35–0.51; P < 0.01) and 3 days (r = 0.27–0.46; P < 0.05) of monitoring. The results indicate that the 3DPAR is a valid instrument for assessing overall, vigorous, and moderate to vigorous physical activity in adolescent girls.
Cognitive and Behavioral Responses to Acute Exercise in Youths: A Review
Authors: Tomporowski Phillip D.
Published: August 2016

A review of the literature indicates that acute bouts of physical activity exert short-term positive benefits on the behavior and cognitive functioning of youths without clinical disorders and on youths who have difficulty focusing attention, controlling impulsive actions, or who evidence high levels of motor activity. Prior research conducted has been largely atheoretical. Information-processing models are suggested to provide a framework for assessing the impact of physical activity and cognition and behavior.
Static and Dynamic Acute Stretching Effect on Gymnasts’ Speed in Vaulting
Authors: Siatras Theophanis , Papadopoulos Georgios , Mameletzi Dimitra , Gerodimos Vasilios , Kellis Spiros
Published: August 2016

Although warm-up and stretching exercises are routinely performed by gymnasts, it is suggested that stretching immediately prior to an activity might affect negatively the athletic performance. The focus of this investigation was on the acute effect of a protocol, including warm-up and static and dynamic stretching exercises, on speed during vaulting in gymnastics. Eleven boys were asked to perform three different protocols consisting of warm-up, warm-up and static stretching and warm-up and dynamic stretching, on three nonconsecutive days. Each protocol was followed by a “handspring” vault. One-way analysis of variance for repeated-measures showed a significant difference in gymnasts’ speed, following the different protocols. Tukey’s post hoc analysis revealed that gymnasts mean speed during the run of vault was significantly decreased after the application of the static stretching protocol. The findings of the present study indicate the inhibitory role of an acute static stretching in running speed in young gymnasts.
Validity of the Multistage 20-M Shuttle-Run Test for Japanese Children, Adolescents, and Adults
Authors: Matsuzaka Akira , Takahashi Yuko , Yamazoe Masayuki , Kumakura Naomi , Ikeda Akiko , Wilk Boguslaw , Bar-Or Oded
Published: August 2016

The purpose of this study was to examine the validity of a 20-m shuttle-run test as an aerobic fitness test for Japanese children, adolescents, and young adults. Participants were 62 boys and 70 girls aged 8–17 years and 56 men and 99 women aged 18–23 years. Stepwise regression analysis was used to elucidate the relationship between shuttle-run performance, age, gender, and anthropometric parameters (as independent variables) and peak oxygen uptake (VO2peak), determined directly on a treadmill, as a dependent variable. We observed high multiple correlations for adults (R2 = .88) and for children and adolescents (R2 = .80). Therefore, it is suggested that our multiple regression equations are more appropriate for predicting VO2peak in Japanese children, adolescents, and adults.
Behavioral and Psychological Factors Related to the Use of Nutritional Ergogenic Aids among Preadolescents
Authors: Pesce Caterina , Donati Alessandro , Magrì Luciana , Cereatti Lucio , Giampietro Michelangelo , Monacelli Carla , Zelli Arnaldo
Published: August 2016

The use of ergogenic aids is common in sport, even among preadolescent athletes (8,15,25). The aim of this study was to investigate the relationship between preadolescents’ use of nutritional ergogenic aids (creatine and amino acids) and gender, age, athletic participation, and sport-relevant psychological factors (i.e., sport success motivation, task and ego orientation, self-efficacy). Two thousand four hundred fifty 11- to 13-year-old children participated in this study. Results suggest that substance use increases with age, especially among male preadolescents; that gender differences are particularly marked among older preadolescents; and that a high commitment to sport training represents a risk factor of ergogenic supplementation only when it is linked to certain psychological dispositions, such as a high ego orientation and a low task orientation.
Predicting Substance Use from Physical Activity Intensity in Adolescents
Authors: McCaul Kerri , Baker Joseph , Yardley John K.
Published: August 2016

Adolescence is characterized as a period of change and adaptation typically marked by a decline in physical activity participation and accompanied by an increase in substance use. The purpose of this study was to examine the relationships among the type (team and individual activity) and intensity (high, medium, and low intensity) of physical activity and substance use (tobacco, marijuana, and alcohol use, and binge drinking) in a sample of 738 adolescents. Results indicated differing relationships among study variables depending on the type and intensity of physical activity and the type of substance used For instance, a positive relationship was found for physical activity intensity and alcohol use, but negative relationships were found for physical activity and tobacco and marijuana use. Collectively, the results reveal that the relationships between physical activity type and intensity and substance use are more complex than previously believed.
Controlling for Maturation in Pediatric Exercise Science
Authors: Baxter-Jones Adam D. G. , Eisenmann Joey C. , Sherar Lauren B.
Published: August 2016

The process of maturation is continuous throughout childhood and adolescence. In a biological context, the effects of a child’s maturation might mask or be greater than the effects associated with exposure to exercise. Pediatric exercise scientists must therefore include an assessment of biological age in study designs so that the confounding effects of maturation can be controlled for. In order to understand how maturation can be assessed, it is important to appreciate that 1 year of chronological time is not equivalent to 1 year of biological time. Sex- and age-associated variations in the timing and tempo of biological maturation have long been recognized. This paper reviews some of the possible biological maturity indicators that the pediatric exercise scientist can use. As a result, we recommend that any of the methods discussed could be used for gender-specific comparisons. Gender-comparison studies should either use skeletal age or some form of somatic index.
Food and Fluid Intake in Adolescent Female Judo Athletes before Competition
Authors: Boisseau Nathalie , Vera-Perez Sonia , Poortmans Jacques
Published: August 2016

Judo is a weight-class sport, meaning that there are weight-defined classes in competitions. Regular body weight restrictions and/or nutritional imbalances can alter growth and maturation states in adolescents. The aim of the present study was to estimate to what extent female judo athletes (age 16.1 ± 0.3 years) modified food and drink intakes 3 weeks and 1 week before competition. Our findings indicate that unbalanced dietary intakes and “weight cutting” might occur in female adolescent competitors. We conclude that dietary recommendations are compulsory in order to educate coaches and young judokas about adequate nutrition and safe weight control behaviors, as well as the dangers of rapid weight loss and dehydration during adolescence.
Ergometer-Specific Relationships between Peak Oxygen Uptake and Short-Term Power Output in Children
Authors: Bloxham Saul R. , Welsman Joanne R. , Armstrong Neil
Published: August 2016

This study examined ergometer-specific relationships between short-term power and peak oxygen uptake (peak VO2) in children. Boys (n = 28) and girls (n = 28) age 11-12 years completed two incremental tests to exhaustion on a cycle ergometer and motorized treadmill for the determination of peak VO2. In addition, they completed two 30 s “all-out” sprint tests, one on a cycle ergometer and one on a nonmotorized treadmill for the assessment of peak power (PP) and mean power (MP). Relationships between peak VO2 and shortterm power measures were examined by sex for cycle- and treadmill-derived data using simple per-body-mass ratios and sample-specific allometric exponents to control for body size differences. From correlational analyses on scaled data, sex differences in responses were shown. In boys, PP and MP were unrelated to peak VO2 for cycle-derived measures but significantly related (r = 0.58 PP; r = 0.69 MP) for treadmill values. PP and MP were significantly related to peak VO2 for both modes of exercise in girls (r = .41−.68). In all but one case, correlation coefficients based on mass-related data were higher than those based on allometrically adjusted data.
Increased Bone Accrual in Premenarcheal Gymnasts: A Longitudinal Study
Authors: Gero Nicole , Cole Jacque , Kanaley Jill , van der Meulen Marjolein , Scerpella Tamara
Published: August 2016

This longitudinal study evaluates the role of impact activity in bone accrual in premenarcheal girls. Twenty-eight gymnasts and 20 controls underwent 1-year analysis; fifteen gymnasts and 8 controls underwent 2-year analysis. Bone mineral density (BMD) was measured yearly by dual energy X-ray absorptiometry. For the 1-year analysis, BMD accrual rates were greater in gymnasts than controls at the forearm only (p < .05). For the 2-year analysis, gains in BMD were 1.5 to 1.9 times greater at the forearm, total hip, and femoral neck for gymnasts (p < .05). These findings confirm the positive effect of impact activity on bone accrual in premenarcheal girls.
The Effect of Upper-Limb Dominance on Forearm Sweating Patterns in Children and Adolescents with Cerebral Palsy
Authors: Unnithan Viswanath B. , Wilk Bogdan
Published: August 2016

The aim of this study was to examine the effect of upper-limb dominance on the forearm sweating pattern in cerebral palsy (CP). Eight boys with CP (13.1 ± 3.1 years) performed three 10-min bouts of an arm-cranking exercise at 35°C, 50% relative humidity. After the third bout, the sweat drops on both forearms were photographed. Sweat gland density (PD) and the average sweat drop area (DA) were determined. PD was significantly higher (p < .05), whereas DA was significantly lower (p < .05) on the nondominant compared with the dominant forearm. The sweating pattern in spastic CP is influenced by upper-limb dominance.
High School Student Inactivity in Sport and Exercise: Arousal Avoidance, Pessimism, and Other Factors
Authors: Kerr John H. , Au Cecilia K. F. , Lindner Koenraad J.
Published: August 2016

As part of a sport and exercise participation questionnaire, samples of Hong Kong high school students (n = 1,496) and high school students entering university (n = 862) completed the Motivational Style Profile (MSP; 4). In addition, 1,493 high school and 848 university entrants completed the MSP-SE, a sport and exercise version of the MSP. Students also completed six extra items related to general life motivational orientations (LMOs) and one other item relating to the frequency of their sport and exercise participation. Based on their answers to this latter item, students were divided into inactive, active, and very active groups and their metamotivational profiles tested for differences. MANOVA techniques produced several significant differences among activity groups in metamotivational dominance and state balance dimensions. The results are presented, and then they are discussed in terms of their implications for sport and exercise provision in high school, university, and more general contexts.
Assessment of Oxygen Deficit during Exercise in Obese Children and Adolescents
Authors: Reybrouck Tony , Vinckx Joseph , Gewillig Marc
Published: August 2016

This study analyzes whether cardiorespiratory exercise performance is impaired in obese children when parameters of aerobic exercise function are used that are independent of body mass. Twenty-one obese patients (mean age 11.6 ± 2.5 years) were studied and compared with 22 normal controls of the same age range (11.4 ± 2.2 years; p = .78). All participants underwent square wave exercise testing on a treadmill for 6 min (speed 5 km/hr, inclination 4%). The oxygen deficit, calculated as ml·min·kg−1, was expressed as a percentage of the total oxygen cost for the 6-min exercise bout (also expressed as ml·min·kg−1). Oxygen deficit amounted to 7.2 ± 1.9% in the obese patients and was not significantly different (p = .25) from the normal controls (6.6 ± 1.1%). The similar values for O2 deficit in obese patients compared with normal controls shows that cardiovascular fitness in obese patients is normal when parameters of aerobic exercise function are not normalized per kg of body mass.
Effect of Body Size on Treadmill Economy in Female Adolescents and Adults
Authors: Grossner Colleen M. , Johnson Emily M. , Cabrera Marco E.
Published: August 2016

Differences in oxygen uptake (VO2) relative to body mass between children and adults walking or running at a given speed might be the result of body size differences. In order to determine whether body size is the main factor affecting these differences in VO2 per kg, we investigated treadmill economy in 10 female adolescents (girls) and 10 women who were matched for body size. There were no significant differences between groups in anthropometrics, stride frequency, or VO2peak. Mean mass-specific VO2 was not significantly different during walking (girls: 12.3 ± 1.7 ml·kg-1·min-1; women: 10.9 ± 1.4 ml·kg-1·min-1) or running (girls: 30.5 ± 3.5 ml·kg-1·min-1; women: 29.0 ± 2.0 ml·kg-1·min-1). Body size appears to have the largest effect on oxygen cost differences usually seen between girls and women during locomotion.
Cross Validation of Fat-Free Mass Prediction Models for Elite Female Gymnasts
Authors: Bauer Patricia W. , Pivarnik James M. , Fornetti Willa C. , Jallo Jennifer J. , Nassar Lawrence
Published: August 2016

The purpose of this investigation was to evaluate three bioelectrical impedance analysis (BIA) prediction models for fat-free mass (FFM) using the U.S. National Women’s Gymnastics team (N = 48; age = 15.8 ± 1.8 years). One model had been developed recently using dual-energy x-ray absorptiometry (DEXA) as the criterion measure, whereas the other two used hydrodensitometry. In this investigation, FFM predictions were compared with measures obtained via DEXA. FFM measured by DEXA averaged 40.5 ± 7.4 kg (± SD), whereas values generated using the three BIA models were within 0.8 kg of this actual measure. Validity coefficients for all models were high (Rxy = .95-98). FFM prediction error was lowest with the model using DEXA as the criterion measure (1.3 kg) compared with the other two (1.9 and 2.4 kg). All BIA models underpredicted FFM in the heaviest girls, and the Lohman and Van Loan et al. models overpredicted FFM in the lightest girls. Whereas prediction error was significantly correlated to the girls’ bone mineral density in all BIA models, this relationship was strongest in the two that were developed using hydrodensitometry.
Relationship between Critical Speed and Endurance Capacity in Young Swimmers: Effect of Gender and Age
Authors: Greco Camila Coelho , Denadai Benedito Sérgio
Published: August 2016

This study analyzed the relationship between critical speed (CS) and maximal speed for 30 min (S30) in swimmers of ages 10-15 years. Fifty-one swimmers were divided by chronological age (10-12 years = G10-12, 13-15 years = G13-15), sexual maturation (pubic hair stages; P1-P3 and P4-P5), and gender (M = boys, F = girls). The CS was determined through the slope of the linear regression between the distances (100, 200, and 400 m) and participants’ respective times. CS and S30 were similar in the younger (G10-12M = 0.97 vs. 0.97 m/s, and G10-12F = 1.01 vs. 0.97 m/s, respectively), and older swimmers (G13-15M = 1.10 vs. 1.07 m/s and G13-15F = 0.93 vs. 0.91 m/s, respectively). In conclusion, the CS can be used in young swimmers for the evaluation of aerobic capacity, independent of gender and age.
Bone and Muscle Geometry in Female Adolescent Middle-Distance Runners
Authors: Greene David A. , Naughton Geraldine A. , Briody Julie N. , Kemp Allan , Woodhead Helen , Farpour-Lambert Nathalie
Published: August 2016

This study compared tibial bone and muscle geometry and total body and regional bone mineral content (BMC) in elite female adolescent middle-distance runners (n = 20, age: 16 ± 1.7 years) and age- and sex-matched controls (n = 20, 16 ± 1.8 years) using magnetic resonance imaging and dual-energy X-ray absorptiometry. Significant advantages were found in athletes compared with controls in bone and muscle geometric values for distal tibial cortical, medullary cavity, distal tibial total muscle and dorsi flexor muscle compartment cross-sectional area, and regional BMC. Results imply mechanical loads associated with middle-distance running might be beneficial to musculoskeletal health in adolescent females.
Physical Activity, Aerobic Fitness, and Causality: Reflections from Complex Adaptive Systems
Authors: Biltz George R.
Published: August 2016

In their article, Kemper and Koppes have presented their assessment of the long-term relationship between physical activity (PA) and aerobic fitness (AF). Specifically, their autoregression analysis did not support a significant causal relationship between current PA and subsequent AF as measured by VO2max. Thus, the authors question how to interpret this unexpected result. Which way does the causal arrow point between PA and AF? This reflection aims to conceptually reframe the causality question, not to resolve its behavioral or physiologic components. This reflection will explore potential sources of unexpected outcomes, analyze dimensions of cognitive difficulty in the context of exercise science, and introduce complex adaptive systems (CAS) as an alternative framework for asking questions and understanding outcomes in exercise research.
Effect of Acute Static Stretching Duration on Isokinetic Peak Torque in Pubescent Soccer Players
Authors: Zakas Athanasios , Doganis George , Galazoulas Christos , Vamvakoudis Efstratios
Published: August 2016

Although athletes routinely perform warm-up and stretching exercises, it has been suggested that prolonged stretching immediately before an activity might negatively affect the force production. Sixteen male pubescent soccer players participated in the study to examine whether a routine duration of acute static stretching is responsible for losses in isokinetic peak torque production. All participants performed two static stretching protocols in nonconsecutive training sessions. The first stretching protocol was performed three times for 15 s (volume 45) and the second 20 times for 15 s (volume 300). Range of motion (ROM) was determined during knee flexion with the use of a goniometer. The peak torque of the dominant leg extensors was measured on a Cybex NORM dynamometer at various angular velocities. The statistical analysis showed that peak torque did not change following the static stretching for 45 s in all angular velocities, while it decreased (p < .001) in all angular velocities following the static stretching for 5 min. The findings suggest that strength decreases after static stretching exercises may be the result of the performed stretching duration.
Judo Training Is More Effective for Fitness Development than Recreational Sports for 7-Year-Old Boys
Authors: Sekulic Damir , Krstulovic Sasa , Katic Ratko , Ostojic Ljerka
Published: August 2016

In this article we compared the effects of 9 months of judo training (JT; N = 41) and recreational sports games training (SGT; N = 57) on the fitness development of 7-year-old boys. Both programs were performed three times per week. Apart from body height, body weight, and skinfold thickness (SUM2SF), changes in muscular and cardiovascular endurance, flexibility, speed, agility, and coordination were studied. Using the analysis of variance, we found no differences between the groups at study entry, but after 9 months the JT participants achieved significantly better results in the shuttle-run task to test agility, the sit-up test for abdominal muscle endurance, and the sit-and-reach test for flexibility. The JT group also maintained their SUM2SF over the 9-month period, whereas the SGT group showed a significant increase in SUM2SF. No differences were observed between the groups in coordination, flexibility of the shoulder joint, speed, endurance, body height, and body weight. In conclusion, the specialized JT allowed the participants to improve more of their fitness capacities compared with nonspecialized SGT.
An Analysis of Sport Identity as a Predictor of Children’s Participation in Sport
Authors: Lau Patrick W.C. , Fox Kenneth R. , Cheung Mike W.L.
Published: August 2016

The purpose of this study was to examine the role of sport identity within a model of children’s sport participation. Participants were 238 boys and 231 girls aged 12 to 13 years from state secondary schools in Hong Kong. Questionnaires were administered in order to assess the influences of psychosocial and socioenvironmental constructs on children’s sport involvement. Regression analyses and path analysis were used to assess hypothesized relationships in the model. Results indicated that sport identity was the strongest predictor of children’s sport participation; perceived sport competence, peer influence, and relative autonomy index (RAI) were predictors of sport identity; and path analysis indicated that the data provided a good fit to the model featuring sport identity as the mediator between psychosocial and socioenvironmental variables and children’s sport participation.
Effect of Carbohydrate Intake during Wrestling Practice on Upper-Body Work in Adolescents
Authors: Horswill Craig A. , Curby Dave G. , Bartoli William P. , Stofan John R. , Murray Robert
Published: August 2016

We examined whether the type of fluid ingested during wrestling training would affect arm ergometry in adolescent athletes. Wrestlers (n = 11) trained for 2-hr sessions and consumed fluid containing 6% carbohydrate or a placebo of equal volume administered double blind and in randomized fashion. To account for training demands across beverage comparisons, energy expenditure (EE) was estimated by using the rate of appearance of CO2 (RaCO2) after 13C-bicarbonate ingestion. The performance test was completed after training and consisted of 6 min of intermittent, high-intensity arm cranking. The results showed the difference in total arm work (kg • m−2 • min) between carbohydrate (2,130 ± 263) and placebo (1,961 ± 401) conditions approached statistical significance (p = .07). Fluid intake matched 50% of sweat loss, resulting in modest dehydration for both treatments. Carbohydrate ingestion during training may enhance high-intensity intermittent arm work in adolescent wrestlers; however, the additive effects of carbohydrate dose and fluid volume for hydration need to be teased apart in subsequent research on adolescents performing such exercise.
Tracking Physical Activity and Sedentary Behavior in Young Children
Authors: Kelly Louise A. , Reilly John J. , Jackson Diane M. , Montgomery Colette , Grant Stanley , Paton James Y.
Published: August 2016

Tracking of total physical activity (PA), moderate to vigorous activity (MVPA), and sedentary behavior was assessed in 42 young children (mean age at baseline 3.8 years) over a 2-year period using the Actigraph accelerometer. Tracking was analyzed using Spearman rank correlations, percentage agreements, and kappa statistics. Spearman rank correlations were r = .35 (p = .002) for total PA, r = .37 (p = .002) for MVPA, and r = .35 (p = .002) for sedentary behavior. Percentage agreements for PA, MVPA, and sedentary behavior were 38, 41, and 26 respectively. Kappa statistics for PA, MVPA, and sedentary behavior ranged from poor to fair. Results suggest low levels of tracking of total physical activity, MVPA, and sedentary behavior in young Scottish children over a 2-year period.
Aerobic-Exercise Training Improves Ventilatory Efficiency in Overweight Children
Authors: Kaufman Christopher , Kelly Aaron S. , Kaiser Dan R. , Steinberger Julia , Dengel Donald R.
Published: August 2016

The objective of this study was to investigate the effect of an 8-week aerobic-exercise training program on ventilatory threshold and ventilatory efficiency in overweight children. Twenty overweight children (BMI > 85th percentile) performed a graded cycle exercise test at baseline and were then randomly assigned to 8 weeks of stationary cycling (n = 10) or a nonexercising control group (n = 10). Ventilatory variables were examined at ventilatory threshold (VT), which was determined via the Dmax method. After 8 weeks, significant improvements occurred in the exercise group compared with the control group for oxygen uptake at VT (exercise = 1.03 ± 0.13 to 1.32 ± 0.12 L/min vs. control = 1.20 ± 0.10 to 1.11 ± 0.10 L/min, p < .05) and ventilatory equivalent of carbon dioxide (VE/VCO2) at VT (exercise = 32.8 ± 0.80 to 31.0 ± 0.53 vs. control = 30.3 ± 0.88 to 31.7 ± 0.91, p < .05). Aerobic-exercise training might help reverse the decrements in cardiopulmonary function observed over time in overweight children.
Calibration of the Biotrainer Pro Activity Monitor in Children
Authors: Welk Gregory J. , Eisenmann Joey C. , Schaben Jodee , Trost Stewart G. , Dale Darren
Published: August 2016

The unique physical and movement characteristics of children necessitate the development of accelerometer equations and cut points that are population specific. The purpose of this study is to develop an ecologically valid cut point for the Biotrainer Pro monitor that reflects a threshold for moderate-intensity physical activity in elementary school children. A sample of 30 children (ages 8−12) wore a Biotrainer monitor while completing a series of 7 movement tasks (calibration phase) and while participating in an organized group activity (cross-validation phase). Videotapes from each session were processed using a computerized direct-observation technique to provide a criterion measure of physical activity. Analyses involved the use of mixed-model regression and receiver operator characteristic (ROC) curves. The results indicated that a cut point of 4 counts/min provides the optimal balance between the related needs for sensitivity (accurately detecting activity) and specificity (limiting misclassification of activity as inactivity). Results with the cross-validation data demonstrated that this value yielded the best overall kappa (.58) and a high classification agreement (84%) for activity determination. The specificity of 93% demonstrates that the proposed cut point can accurately detect activity; however, the lower sensitivity value of 61% suggests that some minutes of activity might be incorrectly classified as inactivity. The cut point of 4 counts/min provides an ecologically valid cut point to capture physical activity in children using the Biotrainer Pro activity monitor.
Comparison of Pedometer and Accelerometer Measures of Physical Activity in Preschool Children
Authors: Cardon Greet , De Bourdeaudhuij Ilse
Published: August 2016

In this study, daily step counts were recorded for 4 consecutive days in 129 four- and five-year-old children. To compare daily Yamax Digiwalker step counts with minutes of engagement in moderate to vigorous physical activity (MVPA), concurrent accelerometer data were collected in a random subsample (n = 76). The average daily step count was 9,980 (± 2,605). Step counts and MVPA minutes were strongly correlated (r = .73, p < .001). The daily step count of 13,874, equating to 1-hr MVPA engagement, was reached by 8% of the children. Daily step counts in preschool children give valid information on physical activity levels—daily step counts in preschoolers are low.
Comparative Validity Assessment of Five Activity Monitors: Does Being a Child Matter?
Authors: Stone Michelle R. , Esliger Dale W. , Tremblay Mark S.
Published: August 2016

The purpose of this study was to determine the effects of age and leg length on the energy-expenditure predictions of five activity monitors. Participants (N = 86, ages 8–40 years) performed three progressive bouts of treadmill activity ranging from 4 to 12 km/hr. Differences between measured energy expenditure (VO2) and activity-monitor-predicted energy expenditure were assessed across five leg length categories to determine the influence of leg length. Accelerometer counts or pedometer steps along with age, weight, and leg length accounted for 85–94% of measured energy expenditure. The addition of age and leg length as predictor variables explained a larger amount of variance in energy expenditure across all speeds. Differences in leg length and age might affect activity-monitor validity and, therefore, should be controlled for when estimating physical activity energy expenditure.
Validation of the Caltrac Movement Sensor Using Direct Observation in Young Children
Authors: Mukeshi Meke , Gutin Bernard , Anderson William , Zybert Patricia , Basch Charles
Published: August 2016

The validity of the Caltrac movement sensor for use with preschool children was assessed. Caltrac-derived values for energy expenditure were compared with those derived via laborious coding of direct observation that involved classification of the child’s videotaped activity every other 5 seconds for an hour in the day-care center or on the playground. Both Caltrac and direct observation values were expressed in kilocalories. The subjects were 20 children with a mean age of 35 months. The correlation coefficient for the total of indoor and outdoor activity was r= .62 (p<.01). The separate correlations for indoor and outdoor activity were r=.56 (p<.05) and r=.48 (p<.05), respectively. However, when the children’s weight, height, age, and sex were factored out of both the Caltrac and direct observation scores, the correlations fell to r= .25 (n.s.), r= .47 (p<.05), and r=.16 (n.s.) for the total, indoor, and outdoor activity, respectively. Thus the Caltrac seemed to record indoor activity (mainly walking) more accurately than it recorded the more varied playground movements, casting doubt on its value as a means of measuring physical activity in children 2-3 years of age.
Disease-Specific Benefits of Training in the Child with a Chronic Disease: What Is the Evidence?
Authors: Bar-Or Oded
Published: August 2016

This review is intended to critically examine the notion that physical training, in addition to its nonspecific effects on fitness, can induce disease-specific benefits in the child with a chronic disease. Conditions included in this analysis are asthma, cerebral palsy, coronary risk, cystic fibrosis, diabetes mellitus, hypertension, myopathies, and obesity. Most of the published intervention studies are deficient in design by not including randomly assigned (or matched) controls. Other constraints stem from the need to simultaneously maintain other therapeutic modalities, the progressive nature of some of the diseases, and the small pool of suitable subjects.
Elevated Blood Pressure in a High School Football Player: Case Presentation and Discussion
Authors: Kaplan Ted A
Published: August 2016

A case is presented of an adolescent high school athlete found to have mildly elevated systolic blood pressure (BP) at the preseason group physical examination. As part of the evaluation to clear him for participation, a graded exercise stress test was performed. The test revealed a systolic BP at peak exercise of 260 mm Hg. The rationale for hygienic and pharmacologic management of this situation is discussed, and the results of this process are detailed. This patient was finally treated with nifedipine after unacceptable results with lisinopril, pindolol, and nonpharmacological approaches. The graded exercise test can be a valuable part of the evaluation of a hypertensive athlete. Besides revealing the occasional dangerous superelevation of BP, the test results can reveal the individual’s cardiovascular response to stress. This can provide insight into the etiology of and prognosis for the patient’s problem. Follow-up testing should be done after any treatment is provided.
Quadriceps Femoris Muscle Voluntary Force and Relaxation Capacity in Children with Spastic Diplegic Cerebral Palsy
Authors: Tammik Karin , Matlep Mariann , Ereline Jaan , Gapeyeva Helena , Pääsuke Mati
Published: August 2016

Isometric voluntary force production and relaxation capacity of the quadriceps femoris (QF) muscle was compared between 12 children with spastic diplegic cerebral palsy (CP) and healthy controls, age 10–11 years. Children with CP had less (p < .05) maximal voluntary-contraction force, voluntary activation, and rate of force development than controls. Visual reaction to contraction did not differ significantly in measured groups, whereas the reaction time to relaxation and halfrelaxation time were longer (p < .05) in children with CP. The authors concluded that in children with CP, the capacity for rapid voluntary force production and relaxation is reduced to a greater extent than isometric maximal force.
Habit Strength of Physical Activity and Sedentary Behavior among Children and Adolescents
Authors: Kremers Stef P.J. , Brug Johannes
Published: August 2016

Internal reliability, convergent validity, and construct validity of the Self-Report Habit Index (SRHI) were examined with respect to physical activity (Study 1) and sedentary behavior (Study 2) among children and adolescents. Internal reliabilities of the SRHI proved to be high in both studies. The SRHI correlated significantly with behavioral frequency measures, as well as with known cognitive associates of these behaviors. Moreover, theory-based moderating influences of habit on the attitude–intention and intention–behavior relationships were identified. The study provides early evidence to support the concept of habit as being important in dealing with physical activity in children.
Longitudinal Stability of Sedentary Behaviors and Physical Activity during Early Adolescence
Authors: Raudsepp Lennart , Neissaar Inga , Kull Merike
Published: August 2016

The purpose of this study was to examine the stability of sedentary behaviors and physical activity in Estonian school children aged 11–12 year at the beginning of the study. In addition, the consequence of changes in sedentary behaviors on a change in physical activity was investigated. Adolescents (N = 345) completed the 3-Day Physical Activity Recall on four occasions over a 22-month period. Results indicated the curvilinear changes in sedentary behaviors and physical activity across time. There was a significant decrease in physical activity and an increase in sedentary behaviors across three years. Stability coefficients indicated a moderate differential stability of the sedentary behaviors (ranged from 0.31 to 0.64) and physical activity (ranged from 0.36 to 0.59) during early adolescence. Latent growth modeling indicated that increase in sedentary behaviors across a 22-month period was inversely associated with a change in physical activity. Interventions targeted at “high-risk” groups to reduce sedentary behaviors during early adolescence are encouraged.
Asymmetry in Volume between Dominant and Nondominant Upper Limbs in Young Tennis Players
Authors: Rogowski Isabelle , Ducher Gaële , Brosseau Olivier , Hautier Christophe
Published: August 2016

This study aimed at demonstrating the asymmetry in volume between the dominant and nondominant upper limbs in tennis players, controlled for maturity status. Upper limb volumes on both sides were calculated in 72 tennis players and 84 control subjects, using the truncated cone method. The participants’ maturity status was determined using the predicted age at peak height velocity (PHV). The results showed significant larger side-to-side asymmetry in volume in tennis groups than in control groups. These findings suggested that, even before PHV, specific-sport adaptations occurred in the dominant upper limb in tennis players.
Effect of Relative Changes in Anthropometry during Childhood on Muscular Power Production in Pedaling: A Biomechanical Simulation
Authors: Korff Thomas , Jensen Jody L.
Published: August 2016

When performing skillful movement muscular and nonmuscular forces act in concert to produce a resultant force that complies with the goal of the task. Nonmuscular forces are directly dependent on the anthropometry of the performer. The purpose of this study was to determine the effect of age-related changes in relative anthropometric characteristics between 5 and 10 years of age on muscular power production during pedaling. A secondary purpose was to determine the dependence of this effect on movement speed. A torque-driven model of two-legged pedaling was used to track experimental kinematics and forces obtained from 6 experienced adult cyclists pedaling at 60 and 120 rpm. Relative anthropometric characteristics were modified to simulate pedaling for children of 5, 7.5, and 10 years of age. Analyses of variance revealed that age-related differences in anthropometry did not affect the muscular contribution to crank power (p > .05), while they had a significant effect on the muscular contribution to limb power (p < .05). Adjustments by the proximal muscle groups (muscles spanning the hip and knee joints) were necessary to account for anthropometry-driven changes in nonmuscular power. These effects were independent of movement speed. Our results provide researchers with useful information to interpret age-related differences in muscular power production more accurately.
Does the Twenty Meter Shuttle-Run Test Elicit Maximal Effort in 11- to 16-Year-Olds?
Authors: Voss Christine , Sandercock Gavin
Published: August 2016

The aim of this study was to determine if maximal effort, evidenced by peak HR was attained during the 20m shuttle-run test in a naturalistic setting. Shuttle-run test performance and peak HR were measured in 208 volunteers (11–16 years). Peak HR was 196 (95% confidence interval (C.I.) 194–198 bpm). The relationship between test performance and peak HR was assessed by regression. There was a weak, but statistically significant relationship between test performance and peak HR (R2 = .029, p = .029) but with such a low coefficient of determination (less than 5% criterion), poor performances were not associated with low peak HR values or underestimation of maximal performance. Peak HR values (196 bpm) were higher than cited criterion values (185 bpm) for maximal effort in laboratory studies. In a naturalistic setting, the 20m shuttle-run test elicits a maximal effort in most children.
Effects of Group- and Individual-Based Step Goals on Children’s Physical Activity Levels in School
Authors: Kang Minsoo , Brinthaupt Thomas M.
Published: August 2016

This study examined the effect of a 6-week school-based pedometer intervention for children. It compared the number of step counts between group- and individual-based step goal conditions over time, and compared the number of goal attainments between the two step goal conditions by physical activity levels. Ninety-nine 4th-grade students’ (50 boys, 49 girls) data were analyzed. Overall step counts continued to increase over time, increasing about 19% from baseline. Different step goal conditions produced similar effects on children’s physical activity levels across all time points. The number of goal attainments was higher for low active children with individual-based step goals than those with group-based step goals. Using pedometers in school is promising for enhancing physical activity in children.
Modifying Middle School Physical Education: Piloting Strategies to Increase Physical Activity
Authors: Jago Russell , McMurray Robert G. , Bassin Stanley , Pyle Laura , Bruecker Steve , Jakicic John M. , Moe Esther , Murray Tinker , Volpe Stella L.
Published: August 2016

Two pilot studies were conducted to examine whether 6th grade students can achieve moderate to vigorous physical activity (MVPA) from 1) activity-based physical education (AB-PE) with 585 participants and 2) a curricular-based (CB-PE) program with 1,544 participants and randomly sampled heart rates during lessons. AB-PE participants spent between 54–66% with a heart rate >140 bpm. CB-PE participants spent between 49–58% with a heart rate >140 bpm. Girls’ mean heart rate was 3.7 bpm lower than the boys. PE can be readily modified so that students spend more than 50% of time in MVPA.
Methodological Approaches for Investigating the Biological Basis for Physical Activity in Children
Authors: Rowlands Ann V.
Published: August 2016

In this insightful article, Eisenmann and Wickel (6) bring together diverse areas of animal and human research to address the issue of the existence of an “activity stat,” or biological basis for activity, outlining the evidence accumulated in this area since Rowland’s excellent commentary in 1998 (10). As the authors state, there has been progress in this area over the last 10 years, however there are still a limited number of studies that specifically address the possible existence of an activity stat in children, whether the strength of this varies by age, sex or culture, the degree of influence of environmental and social factors on this set-point and therefore the crucial question—if activity level is under central control are activity interventions doomed to failure?
Preschool Children Physical Activity Measurement: Importance of Epoch Length Choice
Authors: Vale Susana , Santos Rute , Silva Pedro , Soares-Miranda Luísa , Mota Jorge
Published: August 2016

The purpose of this study was twofold: first to document the gender differences in Moderate to Vigorous Physical Activity (MVPA) according to two epoch systems (5 vs. 60 s) in preschoolers, and, second to document the differences in physical activity (PA) patterns according to two different epoch choices. The sample comprised 59 preschoolers (31 girls) aged 2–5 years old. PA was assessed by accelerometer during school hours. The time spent in MVPA was significantly higher (p < .001) when a 5-s epoch was considered compared to the 60-s epoch, regardless gender. Further, it was found a difference of ?17 min difference between the 2 epoch systems for MVPA. Different epoch times might affect the time spent in MVPA among preschool children.