bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of the RT3 Accelerometer for Measuring Physical Activity of Children in Simulated Free-Living Conditions
Authors: Sun David Xiaoqian , Schmidt Gordon , Teo-Koh Sock Miang
Published: August 2016

This is a validation study of the RT3 accelerometer for measuring physical activities of children in simulated free-living conditions. Twenty-five children age 12–14 years completed indoor testing, and 18 of them completed outdoor testing. Activity counts from the RT3 accelerometer estimated activity energy expenditure (AEE) and the Cosmed K4b2 analyzer measured oxygen uptake. Correlations were found between activity counts and metabolic cost (r = .95, p < .001), metabolic cost and RT3 estimated AEE (r = .96, p < .001) in the indoor test, activity counts and RT3 estimated AEE (r = .97, p < .001) in the outdoor test, and activity counts and metabolic cost when all activities were combined (r = .77, p < .001). Results indicate that the RT3 accelerometer might be used to provide acceptable estimates of free-living physical activity in children.
Sociocultural Correlates of Physical Activity in Children and Adolescents: Findings from the Danish Arm of the European Youth Heart Study
Authors: McMinn Alison M. , van Sluijs Esther M.F. , Wedderkopp Niels , Froberg Karsten , Griffin Simon J.
Published: August 2016

Cross-sectional associations between sociocultural factors and objectively-measured physical activity in a sample of 397 children (aged 9) and 213 adolescents (aged 15) were investigated. Associations with children’s physical activity were found for mothers’ physical activity (β=80,p < .01), parental participation (β=67,p = .01), mother’s age (β=−8,p < .01) and, in girls, fathers’ physical activity (β=73, p = .045; R2 for final model: 10.6%). No sociocultural factors were significantly associated with adolescents’ physical activity. Parental factors might be important targets for interventions to increase children’s physical activity but other factors may have greater influence. For adolescents’ physical activity, factors from other domains may be more important to target.
The Contribution of Stretch-Shortening Cycle and Arm-Swing to Vertical Jumping Performance in Children, Adolescents, and Adult Basketball Players
Authors: Gerodimos Vassilis , Zafeiridis Andreas , Perkos Stefanos , Dipla Konstantina , Manou Vassiliki , Kellis Spiros
Published: August 2016

This study examined from childhood to adulthood: (1) the effects of countermovement (use of stretch-shortening cycle-SSC) and arm-swing (AS) on vertical jumping (VJ) performance and (2) the ability to use the SSC and AS during VJ. Male basketball players (n = 106) were divided according to their age into: children (12.0 ± 0.23), young adolescents (14.5 ± 0.41), old adolescents (16.9 ± 0.27), and adults (21.9 ± 0.32). Each participant executed three maximal squat jumps (SJ), countermovement jumps without arms (CMJ) and with arms (CMJA). The contribution of SSC and AS was calculated by the augmentation (difference and percent change) in performance between CMJ and SJ, and CMJA and CMJ, respectively. CMJA performance was significantly (p < .05) higher than CMJ and SJ, and CMJ was higher than SJ within all age-groups. There were no significant differences (p > .05) among children, young and old adolescents, and adults in the percent contribution of SSC and AS to VJ performance. The variability in the contribution of SSC and AS to VJ performance was about twofold higher in children vs. adults. It appears that the ability to use the SSC and AS is not affected by the maturation process in males, trained in basketball.
Impact of Curriculum-Based Bone Loading and Nutrition Education Program on Bone Accrual in Children
Authors: Nichols David L. , Sanborn Charlotte F. , Essery Eve V. , Clark Rachel A. , Letendre Jennifer D.
Published: August 2016

The purpose of this study was to investigate the influence of jumping activities and nutrition education on bone accretion in prepubescents. Fourth-grade children were divided into four groups: jumping (n = 61), nutrition (n = 9), jumping plus nutrition (n = 14), and control (n = 28). Interventions spanned the fourth and fifth grade academic years. Assessments were gathered at 0, 8 and 20 months. Baseline BMD values were (mean ± SD): lumbar (0.752 ± 0.095 g/cm2), neck (0.794 ± 0.089 g/cm2) and total (0.907 ± 0.060 g/cm2). There was a significant increase in BMD over time. However, the interventions produced no significant effects. Twice weekly jumping and/or biweekly nutrition education did not influence bone accrual.
Critical Hours: Physical Activity and Sedentary Behavior of Adolescents after School
Authors: Atkin Andrew J. , Gorely Trish , Biddle Stuart J.H. , Marshall Simon J. , Cameron Noel
Published: August 2016

The present study examined physical activity and sedentary behavior patterns of adolescents between 15.30h and 18.30h. The sample for this study is 1,484 (boys: n = 561; girls: n = 923). Boys and girls reported 21 and 19 min of physical activity and 24 and 26 min of homework respectively during this period. Technology-based sedentary behavior (TV viewing, computer and video game use) was significantly higher in boys than girls (boys = 50 mins; girls = 35 mins; p < .05). The most prevalent behaviors after school are technology-based sedentary behavior, homework and physical activity. During these hours, engagement in physical activity does not appear to displace time spent doing homework.
Validity of Fat-Free Weight Equations for Estimating Mean and Peak Power in High School Wrestlers
Authors: Zuniga Jorge , Housh Terry J. , Mielke Michelle , Camic Clayton L. , Hendrix C. Russell , Johnson Glen O. , Housh Dona J. , Schmidt Richard J.
Published: August 2016

The purpose of this study was to cross-validate the fat-free weight (FFW) equations derived on nonathletic children and adolescents for estimating mean power (MP) and peak power (PP) in high school wrestlers. One hundred and three male high school wrestlers performed the Wingate Anaerobic Test to estimate MP and PP, as well as underwater weighing to determine FFW. The follow equations were used to estimate the MP and PP of the wrestlers in the current study.

MP (W) = 9.3 (FFW) − 109.8 EQ.1

PP (W) = 14.1 (FFW) − 162.1 EQ.2

The results in the current study indicated that as percent of the mean values, the equation that predicted MP resulted in a substantially greater total error (TE; 19.9% of the mean) than the equation that predicted PP (8.3% of the mean). These findings indicated that the equation that was derived on nonathletes did not accurately estimate MP in the high school wrestlers. The equation for estimating PP, however, was valid when applied to the current sample of high school wrestlers. These findings supported previous studies that have shown that in adolescent males, exercise training improves the metabolic capabilities of the anaerobic glycolytic system, but not the phosphagen system.
Environmental and Safety Barriers to Youth Physical Activity in Neighborhood Parks and Streets: Reliability and Validity
Authors: Durant Nefertiti , Kerr Jacqueline , Harris Sion Kim , Saelens Brian E. , Norman Gregory J. , Sallis James F.
Published: August 2016

Few studies have explored barriers to physical activity in parks and streets among children, adolescents, and their parents. The purpose of this article is to evaluate the psychometric properties of a new survey of barriers to physical activity in neighborhood parks and streets. Adolescents and parents of children and adolescents completed surveys twice. Two barrier subscales (environment and safety) emerged that applied to both locations and all participant groups. Results generally supported acceptable, internal consistency as well as construct validity, but test-retest reliabilities were lower than desired. These scales may be used to improve understanding of perceptions of barriers to physical activity in neighborhood parks and streets, but further development is needed.
Physical Fitness and Developmental Coordination Disorder in Greek Children
Authors: Tsiotra Georgia D. , Nevill Alan M. , Lane Andrew M. , Koutedakis Yiannis
Published: August 2016

We investigated whether children with suspected Developmental Coordination Disorder (DCD+) demonstrate different physical fitness levels compared with their normal peers (DCD−). Randomly recruited Greek children (n = 177) were assessed for body mass index (BMI), flexibility (SR), vertical jump (VJ), hand strength (HS), 40m dash, aerobic power, and motor proficiency. ANCOVA revealed a motor proficiency (i.e., DCD group) effect for BMI (p < .01), VJ (p < .01), and 40m speed (p < .01), with DCD+ children demonstrating lower values than DCD−. Differences between DCD+ and DCD− were also obtained in log-transformed HS (p < .01). These findings suggest that intervention strategies for managing DCD should also aim at physical fitness increases.
Gender Similarities and Differences in Factors Associated with Adolescent Moderate-Vigorous Physical Activity
Authors: Wenthe Phyllis J. , Janz Kathleen F. , Levy Stephen M.
Published: August 2016

This study investigated the relationship between predisposing, reinforcing, and enabling factors conceptualized within the Youth Physical Activity Promotion Model (YPAP) and moderate to vigorous physical activity (MVPA) of adolescent males and females. Specifically, self-efficacy to overcome barriers, enjoyment of physical activity; family support, peer support, perceived school climate, neighborhood safety and access to physical activity were examined. The Physical Activity Questionnaire for Adolescents (PAQ-A) and the Actigraph 7164 were used to obtain three different measures of MVPA in 205 adolescents (102 males, 103 females). Family support emerged as the most significant and consistent factor associated with the MVPA of both adolescent males and females. This relationship was noted even when different methods of measuring MVPA were employed. These findings should increase the confidence of public health officials that family support has the potential to positively alter the physical activity behavior of adolescents.
Is Fitness Level in Childhood Associated with Physical Activity Level as an Adult?
Authors: Trudeau François , Laurencelle Louis , Shephard Roy J.
Published: August 2016

The purpose of this study was to examine the possible influence of childhood physical fitness on physical activity level and some of its psychosocial determinants as an adult. Childhood (age 10–12 years) data from the longitudinal Trois-Rivières Growth and Development Study (body mass index, Physical Work Capacity (PWC170)), number of sit-ups/min, left + right hands grip strength) were correlated with adult data (age 35.0 ± 0.3 years) for physical activity (PA) level, attitude toward PA, intention to exercise, perceived barriers to exercise and support of an active lifestyle by significant others. No significant relationships between childhood physical fitness and adulthood PA were found. Although the sample size is relatively small, our data suggest that the preadolescent physical fitness level has no measurable impact on adult habitual PA, attitudes toward PA, intentions to exercise, perceived barriers to exercise or support from the individual’s entourage.
Examination of Physical Activity in Adolescents Over the School Year
Authors: Bruner Mark W. , Chad Karen E. , Beattie-Flath Jodie A. , Humbert M. Louise , Verrall Tanya C. , Vu Lan , Muhajarine Nazeem
Published: August 2016

This study monitored the physical activity behavior of adolescent students over a ten month school year. Physical activity was assessed at two month intervals using selfreport and objective (Actical accelerometers) measures. Self-report results (n = 547) indicated a decline in physical activity throughout the school year for all grades and genders. The decline was attributed largely to a decrease in organized activity participation. Objective physical activity results (n = 40) revealed a significant decline in activity in the latter half of the school year (February to June). Declining physical activity was attributed to a decrease in vigorous activity which was consistent across grade and gender. Collectively, the results highlight the importance of promoting consistent opportunities for adolescents to be active throughout the school year.
Predicting Maximal Lactate Steady State in Children and Adults
Authors: Beneke Ralph , Heck Hermann , Hebestreit Helge , Leithäuser Renate M
Published: August 2016

The value of blood lactate concentration (BLC) measured during incremental load tests in predicting maximal lactate-steady-state (MLSS) workload has rarely been investigated in children. In 17 children and 18 adults MLSS was 4.1 ± 0.9mmol 1.1. Workload at BLC of 3.0mmol 1.1 determined during an incremental load test explained about 80% of the variance (p < .001) and best predicted MLSS workload independent of age. This was despite the increase in power per time related to maximum incremental load test power being higher (p < .001) in children than in adults. The BLC response to given exercise intensities is faster in children without affecting MLSS.
Physical Characteristics and Physiological Attributes of Adolescent Volleyball Players—A Review
Authors: Lidor Ronnie , Ziv Gal
Published: August 2016

The purpose of this article was to review a series of studies (n = 31) on physical characteristics, physiological attributes, and volleyball skills of female and male adolescent volleyball players. Among the main findings were (a) that male national players were taller and heavier than state and novice players, while female national players showed lower body fat values compared with state and novice players, and (b) vertical jump values were higher in starters versus nonstarters. Among the methodological concerns based on the reviewed studies were the lack of information on maturational age and lack of longitudinal studies. It was recommended that a careful selection of physiological tests should be made when assessing the abilities of adolescent volleyball players.
A Multivariate Analysis of Performance in Young Swimmers
Authors: Saavedra José M. , Escalante Yolanda , Rodríguez Ferran A.
Published: August 2016

This study develops multivariate models to predict swimming performance based on multidimensional assessment. 66 male (age 13.6 ± 0.6 y) and 67 female (11.5 ± 0.6 y) swimmers undertook a test battery including a sports background and training questionnaire, anthropometry, general and specific fitness tests, and technique. Competitive performance (LEN scores in three best events) was the predicted variable. A multiple linear regression model explained 82.4% of performance variability in males (based on age, sitting height, 30-min test, 6 × 50 m at 1:30, and swimming index) and 84.5% in females (age, 30-min test, 6 × 50 m at 1:30, and velocity at 50 m). Discriminant analysis using a four-group split-sample approach correctly classified 94.1% of the best male swimmers (based on age, 30-min test, 6 × 50 m at 1:30, shoulder extension, arm span, and height), and 71.0% of the best females swimmers (30-min test, horizontal floating, velocity at 50 m, and age). Chronological age was the main predictor of performance in this age category. Main predictive variables pertained to the anthropometric (particularly in males), specific fitness (aerobic speed and endurance), and technical domains (particularly in females). In these ages competitions should be organized according to year of birth and not by age categories.
Longitudinal Changes in the Oxygen Uptake Kinetic Response to Heavy-Intensity Exercise in 14- to 16-Year-Old Boys
Authors: Breese Brynmor C. , Williams Craig A. , Barker Alan R. , Welsman Joanne R. , Fawkner Samantha G. , Armstrong Neil
Published: August 2016

This study examined longitudinal changes in the pulmonary oxygen uptake (pV̇O2) kinetic response to heavy-intensity exercise in 14–16 yr old boys. Fourteen healthy boys (age 14.1 ± 0.2 yr) completed exercise testing on two occasions with a 2-yr interval. Each participant completed a minimum of three ‘step’ exercise transitions, from unloaded pedalling to a constant work rate corresponding to 40% of the difference between the pV̇O2 at the gas exchange threshold and peak pV̇O2 (Δ). Over the 2-yr period a significant increase in the phase II time constant (25 ± 5 vs. 30 ± 5 s; p = .002, ω2 = 0.34), the relative amplitude of the pV̇O2 slow component (9 ± 5 vs. 13 ± 4%; p = .036, ω2 = 0.14) and the pV̇O2 gain at end-exercise (11.6 ± 0.6 vs. 12.4 ± 0.7 mL·min−1·W−1; p < .001, ω2 = 0.42) were observed. These data indicate that the control of oxidative phosphorylation in response to heavy-intensity cycling exercise is age-dependent in teenage boys.
Reproducibility of Measurement of Muscle Deoxygenation in Children During Exercise
Authors: Leclair Erwan , Thevenet Delphine , Reguem Sophie C. , Borel Benoit , Baquet Georges , Berthoin Serge , Mucci Patrick
Published: August 2016

This study was designed to test the reproducibility of muscle oxygenation by NIRS in children during exercise. Twelve healthy non-obese and non-trained children performed one maximal graded test, and four 6-min constant load cycle exercises. Deoxy-hemoglobin (Hb/Mb-H+) data were averaged every 1, 5, 10, 20 and 30s. Hb/Mb-H+ data averaged every 5, 10, 20 and 30s showed good reproducibility. When averaged every second, Hb/Mb-H+ values were reproducible after the first minute of exercise. Based on 1s averaged signal modeling, time period and t values for Hb/Mb-H+ were not reproducible but mean response time values showed an acceptable reproducibility.
Performance of Young Male Swimmers in the 100-Meters Front Crawl
Authors: de Mello Vitor Fabrício , Böhme Maria Tereza Silveira
Published: August 2016

Youth swimming performance may be influenced by anthropometric, physiology and technical factors. The present paper examined the role of these factors in performance of 100m freestyle in swimmers 12–14 years of age (n = 24). Multiple regression analysis (forward method) was used to examine the variance of the 100 meters front crawl. Anaerobic power, swimming index and critical speed explained 88% (p < .05) of the variance in the average speed of 100 meters front crawl among young male pubertal swimmers. To conclude, performance of young swimmers in the 100 meters front crawl is determined predominantly by physiological factors and swimming technique.
Oxygen Uptake Efficiency Slope in Healthy Children
Authors: Akkerman Moniek , van Brussel Marco , Bongers Bart C. , Hulzebos Erik H.J. , Helders Paul J.M , Takken Tim
Published: August 2016

The objective of this study was to investigate the characteristics of the submaximal Oxygen Uptake Efficiency Slope (OUES) in a healthy pediatric population. Bicycle ergometry exercise tests with gas-analyses were performed in 46 healthy children aged 7–17 years. Maximal OUES, submaximal OUES, V̇O2peak, VEpeak, and ventilatory threshold (VT) were determined. The submaximal OUES correlated highly with V̇O2peak, VEpeak, and VT. Strong correlations were found with basic anthropometric variables. The submaximal OUES could provide an objective, independent measure of cardiorespiratory function in children, reflecting efficiency of ventilation. We recommend expressing OUES values relative to Body Surface Area (BSA) or Fat Free Mass (FFM).
Time-of-Day Effects on Short-Term Exercise Performances in 10- to 11-Year-Old Boys
Authors: Souissi Hichem , Chaouachi Anis , Chamari Karim , Dogui Mohamed , Amri Mohamed , Souissi Nizar
Published: August 2016

The purpose of this study was to examine the time-of-day effects on short-term performances in boys. In a balanced and randomized study design, 20 boys performed four anaerobic tests of strength and power (grip strength, Squat-Jump, Five-jump and cycle Wingate tests) at 08:00, 14:00 and 18:00 hr on separate days. The results showed a time-of-day effect on oral temperature. Analysis of variance revealed a significant time-of-day effect for short-term performances for strength, cycle, and jump tests. The post hoc analysis revealed that performances improved significantly from morning to afternoon but no significant differences were noticed between 14:00 and 18:00 hr. The differences between the morning and the afternoon (the highest value measured either at 14:00 or at 18:00 hr) reached 5.9% for grip strength, 3.5% for the squat jump test, 5% for the five jump test, and 5.5% for Ppeak and 6% for Pmean during the Wingate test. A significant positive correlation was found between temperature and short-term performances. In conclusion, a time-of-day effect in the child’s maximal short-term exercise performances exists in relation with core temperature. Such variations would have pronounced effects when expressed in training programs and competitions.
Reliability of Squat and Countermovement Jump Tests in Children 6 to 8 Years of Age
Authors: Acero Rafael Martín , Olmo Miguel Fernández-del , Sánchez José Andrés , Otero Xosé Luis , Aguado Xavier , Rodríguez Ferrán A.
Published: August 2016

The aim of this study was to determine the reliability of the squat jump test (SJ) and countermovement jump test (CMJ), in fifty-six children (30 girls and 26 boys) with ages ranging from 6 to 8 years. Each subject performed two evaluation sessions (T1, T2) with seven days between tests. The results show that the CMJ test has a high intratrial reproducibility in T1 and T2 measured through intraclass correlation coefficient (ICC ≥ 0.95). The ICC for the SJ test had a high value (0.99) only in T1. The variability for both tests among children under 9 years of age is higher than those reported for adult subjects in other studies. The intersession reliability was questionable with a high methodical error (ME= 9.86–15.1%, for the SJ and CMJ, respectively) and a significant worsening of the results of CMJ in T2 (p < .05).
Bone Speed of Sound and Physical Activity Levels of Overweight and Normal-Weight Girls and Adolescents
Authors: Yao Mathew , Ludwa Izabella , Corbett Lauren , Klentrou Panagiota , Bonsu Peter , Gammage Kimberley , Falk Bareket
Published: August 2016

Bone properties, reflected by speed of sound (SOS), and physical activity levels were examined in overweight (OW) girls (n = 19) and adolescents (n = 22), in comparison with normal-weight (NW) girls (n = 21) and adolescents (n = 13). Moderate-to-vigorous physical activity (MVPA) was higher in NW than in OW in both age groups. Tibial SOS was lower in OW compared with NW in both age groups. MVPA correlated with tibial SOS, once age was partialed out. The results suggest that overweight girls and adolescents are characterized by low tibial SOS, which may be partially attributed to lower physical activity levels.
Predictors of VO2Peak in Children Age 6- to 7-Years-Old
Authors: Dencker Magnus , Hermansen Bianca , Bugge Anna , Froberg Karsten , Andersen Lars B.
Published: August 2016

This study investigated the predictors of aerobic fitness (VO2PEAK) in young children on a population-base. Participants were 436 children (229 boys and 207 girls) aged 6.7 ± 0.4 yrs. VO2PEAK was measured during a maximal treadmill exercise test. Physical activity was assessed by accelerometers. Total body fat and total fat free mass were estimated from skinfold measurements. Regression analyses indicated that significant predictors for VO2PEAK per kilogram body mass were total body fat, maximal heart rate, sex, and age. Physical activity explained an additional 4–7%. Further analyses showed the main contributing factors for absolute values of VO2PEAK were fat free mass, maximal heart rate, sex, and age. Physical activity explained an additional 3–6%.
Active Travel to School and Physical Activity Levels of Irish Primary Schoolchildren
Authors: Murtagh Elaine M. , Murphy Marie H.
Published: August 2016

The purpose of this study was to (1) determine the physical activity levels of 9–11 year old children, and (2) compare the activity levels of children who commute to school by active and passive modes. 140 children aged 9–11 years (85 boys) were recruited from four urban Irish schools. Mode of commuting was assessed by questionnaire. Step counts were measured for 4 consecutive days. Mean daily step counts for the sample were 14386 ± 5634. Boys were significantly more active than girls (15857 ± 5482 vs. 12113 ± 5127 steps). Eighty-seven children (62.1%) traveled by car, 51 children (36.4%) walked to school, one child traveled by bus and one child cycled. Children who walked or cycled to school had higher daily step counts than those who traveled by passive modes (16118 ± 5757 vs. 13363 ± 5332 steps). Active commuting to school may therefore represent a worthwhile strategy for improving children’s physical activity levels.
Physical Activity Levels to Estimate the Energy Requirement of Adolescent Athletes
Authors: Carlsohn Anja , Scharhag-Rosenberger Friederike , Cassel Michael , Weber Josefine , Guzman Annette de Guzman , Mayer Frank
Published: August 2016

Adequate energy intake in adolescent athletes is considered important. Total energy expenditure (TEE) can be calculated from resting energy expenditure (REE) and physical activity level (PAL). However, validated PAL recommendations are available for adult athletes only. Purpose was to comprise physical activity data in adolescent athletes and to establish PAL recommendations for this population. In 64 competitive athletes (15.3 ± 1.5yr, 20.5 ± 2.0kg/m2) and 14 controls (15.1 ± 1.1yr, 21 ± 2.1kg/m2) TEE was calculated using 7-day activity protocols validated against doubly-labeled water. REE was estimated by Schofield-HW equation, and PAL was calculated as TEE:REE. Observed PAL in adolescent athletes (1.90 ± 0.35) did not differ compared with controls (1.84 ± 0.32, p = .582) and was lower than recommended for adult athletes by the WHO. In conclusion, applicability of PAL values recommended for adult athletes to estimate energy requirements in adolescent athletes must be questioned. Instead, a PAL range of 1.75–2.05 is suggested.
Assessing Youth Sprint Ability–Methodological Issues, Reliability and Performance Data
Authors: Rumpf Michael C. , Cronin John B. , Oliver Jon L. , Hughes Michael
Published: August 2016

The primary purpose of this paper was to provide insight into the methodological issues and associated reliability of assessments used to quantify running sprint ability in youth athletes aged 8–18 years. Over-ground sprinting was the most reliable and common used choice of assessment to measure sprint performance of youth. In addition, the performance data of those athletes over distances ranging from 5 to 40 meters was collated from 34 published articles and tabulated with regards to the athlete’s chronological age. Torque or nonmotorized treadmills have been used to quantify sprint performance in youth with acceptable reliability, this technology providing deeper insight into sprint kinetics and kinematics; however there is limited performance data on youth using the torque and the nonmotorized treadmill. It is suggested that future research should use this technology in youth to better understand changes associated with growth, maturation and training.
Intrapersonal, Behavioral and Environmental Factors Associated With Meeting Recommended Physical Activity Among Rural Latino Youth
Authors: Perry Cynthia K. , Saelens Brian E. , Thompson Beti
Published: August 2016

This study aimed to identify intrapersonal, behavioral, and environmental factors associated with engaging in recommended levels of physical activity among rural Latino middle school youth. Data were from an anonymous survey of 773 Latino youth (51% female) about level of and barriers and motivators to physical activity, risk behaviors, and park use. Logistic regression models identified factors correlated with meeting recommended levels of physical activity (5 days or more 360 min/day). Thirty-four percent of girls and 41% of boys reported meeting this physical activity recommendation. Participation in an organized after school activity (p < .001) and in physical education (PE) classes 5 days a week (p < .001) were strongly associated with meeting recommended physical activity level. Making PE available 5 days a week and creating opportunities for organized after school physical activity programs may increase the number of rural Latino middle school youth who meet recommended physical activity level.
Analyses of Gait and Jump Tasks in Female Obese Adolescents
Authors: de Carvalho Filipe Ricardo Pires , Martins Ana Teresa da Conceição Figueira , Teixeira Ana Maria Miranda Botelho
Published: August 2016

In spite of the advances in knowledge on the multi–factorial nature of obesity, many questions related to the consequences of the disease continue to be unanswered. Several studies have reported biomechanic and kinematic adaptation and alterations in walking and in tasks of every day life, motivated by the additional load of fat mass in children and adults. The main objective of this study was to understand the effect of obesity in the electromyographic activity of four lower extremity muscles during three speeds of walking and during a countermovement jump (CMJ) in twenty two (9 obese and 13 normal weight) female adolescents aged 13. Although electromyographic differences were not observed between groups for normal, slow and fast speeds, data suggests that the preferred pace of the obese is less efficient than that of the normal weight group. In CMJ task, differences in the after–fall jump phase were observed. More studies are needed to explain if the few differences observed between groups are caused by the bigger amount of fat mass.
Test-Retest Reliability and Validity of a Child and Parental Questionnaire on Specific Determinants of Cycling to School
Authors: Ducheyne Fabian , De Bourdeaudhuij Ilse , Lenoir Matthieu , Cardon Greet
Published: August 2016

This study examined the reliability of a newly developed child and parental questionnaire on specific determinants of cycling to school among 10–12 year olds. Validity of child reported distance, bicycle equipment and basic bicycle skills was also investigated. In total 211 children and 33 parents participated in this study. The reliability of the questionnaires was acceptable with results indicating reliability ranging from fair to perfect agreement. Therefore, the questionnaires appear to be reliable tools for assessing specific determinants of cycling to school. Furthermore, it was found that children overestimate their abilities to perform basic bicycle skills. This suggests that objectively measuring bicycle skills is preferred to child reported skills assessment.
Evaluation of a Redesigned Outdoor Space on Preschool Children’s Physical Activity During Recess
Authors: Nicaise Virginie , Kahan David , Reuben Karen , Sallis James F.
Published: August 2016

This study investigated the impact of renovation and redesign of a university preschool’s outdoor space on children’s sedentary behavior, light activity, and moderate-to-vigorous-physical-activity (MVPA) during unstructured recess. Physical activity was measured by accelerometry and direct observation in two independent samples of 50 (baseline) and 57 (postintervention) children (Mage=4.4 yrs ± 0.5). Controlling for gender, age, BMI and recess length, observational data, but not accelerometry, revealed a significant decrease in intervals spent sedentary (-26.5%) and increases in light physical activity (+11.6%) and MVPA (+14.9%). Higher levels of MVPA were associated with specific environmental changes (new looping cycle path, OR = 2.18; increased playground open space, OR = 7.62; and new grass hill, OR = 3.27). Decreased sedentary behavior and increased light activity and MVPA may be realized with environmental changes that promote continuous and novel movement experiences in more expansive spaces.
Linking Selected Kinematic, Anthropometric and Hydrodynamic Variables to Young Swimmer Performance
Authors: Morais Jorge E. , Jesus Sérgio , Lopes Vasco , Garrido Nuno , Silva António , Marinho Daniel , Barbosa Tiago M.
Published: August 2016

The aim of this study was to develop a structural equation model (i.e., a confirmatory technique that analyzes relationships among observed variables) for young swimmer performance based on selected kinematic, anthropometric and hydrodynamic variables. A total of 114 subjects (73 boys and 41 girls of mean age of 12.31 ± 1.09 years; 47.91 ± 10.81 kg body mass; 156.57 ± 10.90 cm height and Tanner stages 1–2) were evaluated. The variables assessed were the: (i) 100 [m] freestyle performance; (ii) stroke index; (iii) speed fluctuation; (iv) stroke distance; (v) active drag; (vi) arm span and; (vii) hand surface area. All paths were significant (p < .05). However, in deleting the path between the hand surface area and the stroke index, the model goodness-of-fit significantly improved. Swimming performance in young swimmers appeared to be dependent on swimming efficiency (i.e., stroke index), which is determined by the remaining variables assessed, except for the hand surface area. Therefore, young swimmer coaches and practitioners should design training programs with a focus on technical training enhancement (i.e., improving swimming efficiency).
Moderate-Intensity Aerobic Training Program Improves Insulin Sensitivity and Inflammatory Markers in a Pilot Study of Morbidly Obese Minority Teens
Authors: Many Gina , Hurtado Maria-Eugenia , Tanner Charles , Houmard Joseph , Gordish-Dressman Heather , Park Jung-Jun , Uwaifo Gabriel , Kraus William , Hagberg James , Hoffman Eric
Published: August 2016

We initiated a pilot study to investigate the effects of 8 wks of aerobic exercise training (ET) on insulin sensitivity and inflammatory markers in obese and insulin-resistant minority adolescents. Eleven morbidly obese (BMI 41.4 ± 1.8 kg/m2) minority adolescents were entered into a supervised ET intervention (~180 min/wk at 40–55%VO2PeakR [(VO2Peak − VO2Rest)/VO2Rest]). The effects of training on insulin sensitivity (SI), inflammation and other metabolic syndrome features were examined. Results: Insulin action improved in response to training, as indicated by a ~37% increase in SI (p = .018). Plasma levels of several proinflammatory cytokines were reduced in response to ET, as indicated by significant decrements in sTNF-R, CCL2, MPO, IL-6, resistin, and leptin, with no significant changes in hsCRP. ET induced reductions in BMI and percent total body fat. Conclusions: The present study supports the efficacy of ET interventions on metabolic syndrome features in morbidly obese minority youth.

Nosotros iniciamos un estudio piloto para investigar los efectos de 8 semanas de entrenamiento con ejercicios aeróbicos (EA) sobre la sensibilidad insulinica y los marcadores inflamatorios en un grupo minoritario de adolescentes abesos con resistencia a lá insulina. Once adolescentes con obesidad mórbida (IMC 41, 4+1.8kg/m2) fueron asignados a un grupo de intervención que realizo un EA supervisado (~180 min/semana al 40-55%VO2 picoR [(VO2Pico − VO2Reposo)/VO2Reposo]). Se analizo el efecto del entrenamiento sobre la sensibilidad insulinica (IS), inflamación y otras características del síndrome metabòlico. RESULATDOS: El incremento del 37% en la SI (p = 0.018) indico que La acción de la insulina mejora en respuesta al entrenamiento. Como indican la disminución significativa de sTNF-R, CCL2, MPO, IL-6, resistina, and leptina, y la falta de cambios significativos en hsCR, los niveles plasmáticos de varias citoquinas proinflamatorias se redujeron en respuesta al EA. Además, el entrenamiento produjo una reducción del IMC y del porcentaje de grasa corporal. CONCLUSIONES: Los resultados del presente estudio apoyan la eficacia de una intervención con EA sobre las características del síndrome metabólico en un grupo minoritario de adolescentes con obesidad mórbida.
Influence of Pubertal Stage on Local Sweating Patterns of Girls Exercising in the Heat
Authors: Wilk Boguslaw , Pender Nola , Volterman Kim , Bar-Or Oded , Timmons Brian W.
Published: August 2016

The influence of puberty on sweating patterns of girls exercising in the heat is not known. Nine- to 17-year-old girls, representing 4 stages of breast development: T1 (n = 21); T2 (n = 22); T3 (n = 25); and T4 (n = 22), cycled for 20 min at 60% in 35 °C. The population density of heat activated sweat glands was higher in T1 vs T3 and T4 and in T2 vs T4. Sweat drop area was lower in T1 vs T3 and in T1 vs T4, T2 vs T4 and T3 vs T4. The proportion of skin covered by sweat was lower in T1 vs T4. Sweating patterns of girls exercising in the heat are influenced by pubertal stage.
A Feasibility Study of the Effect of Intra-Articular Corticosteroid Injection on Isokinetic Muscle Strength in Children With Juvenile Idiopathic Arthritis
Authors: McKay Damien , Ostring Genevieve , Broderick Carolyn , Chaitow Jeffrey , Singh-Grewal Davinder
Published: August 2016

This study assessed the magnitude of changes in isokinetic muscle strength in children with juvenile idiopathic arthritis (JIA) before and after treatment with intra-articular corticosteroid injection and assessed the feasibility of a larger study of the same effect. Isokinetic dynamometry was used to measure peak knee extension and flexion torque in 12 children before and after treatment for unilateral knee arthritis. Extensor and flexor strength was reduced on the affected side before treatment (-0.56Nm/kg, p = .004 and −0.24Nm/kg, p = .02 respectively). Increases in extensor strength were observed at two weeks (p = .01) and twelve weeks postinjection (p = .03). Improvements at 6 weeks approached but did not reach statistical significance (p = .17). Improvements in flexor strength were not observed until 12 weeks postinjection (p = .03). Despite significant improvements in extensor strength, low peak knee extensor torque continued to be observed at 12 weeks (p = .01). Knee extensor and flexor strength is reduced in children with JIA with active arthritis and improves following intra-articular corticosteroid injection. Significant improvements in knee extensor and flexor strength were seen postinjection; however deficits in extensor strength were still evident at three months. Isokinetic dynamometry was safe and well tolerated in our sample of children with JIA with active arthritis.
Light Activity Following a Meal and Postprandial Cardiometabolic Risk in Adolescents
Authors: Sisson Susan B. , Gibson Ashley E. , Short Kevin , Gardner Andrew W. , Whited Teresa , Robledo Candace , Thompson David M.
Published: August 2016

The purpose of this study was to determine if light physical activity (LPA) minimizes the impairment of cardiometabolic risk factors following a typical meal in adolescents. Eighteen adolescents (50% male, 14.8 ± 2.3 yrs) consumed a meal (32% fat, 14% protein, 53% carbohydrate), then completed a walking (1.5mph for 45 min of each hour) or sitting treatment for 3 hr in randomized order on separate days. Following the meal, HDL cholesterol declined 4.8% but remained higher during walking at 3 hr (42.1mg/dl ± 9.3) than sitting (8.4% decline; 40.5mg/dL ± 9.9; treatment × time interaction, p < .03). The 3-hr insulin was lower after walking (24.8μIU/ml ± 33.4) than sitting (37.8μIU/ml ± 34.7; treatment × time interaction, p < .0001). Triglycerides increased by ~40% above baseline at 1 and 2 hr, with higher values for walking (treatment × time interaction, p < .02). However by 3 hr, triglycerides were not different from baseline. Area under the curve (AUC) analyses were not significantly different between treatments for any outcomes. Although minor, LPA appears to mitigate the undesirable postprandial changes in HDL cholesterol and insulin but not triglycerides, following a typical meal in adolescents.
Physical Activity Problem-Solving Inventory for Adolescents: Development and Initial Validation
Authors: Thompson Debbe , Bhatt Riddhi , Watson Kathy
Published: August 2016

Youth encounter physical activity barriers, often called problems. The purpose of problem solving is to generate solutions to overcome the barriers. Enhancing problem-solving ability may enable youth to be more physically active. Therefore, a method for reliably assessing physical activity problem-solving ability is needed. The purpose of this research was to report the development and initial validation of the physical activity problem-solving inventory for adolescents (PAPSIA). Qualitative and quantitative procedures were used. The social problem-solving inventory for adolescents guided the development of the PAPSIA scale. Youth (14- to 17-year-olds) were recruited using standard procedures, such as distributing flyers in the community and to organizations likely to be attended by adolescents. Cognitive interviews were conducted in person. Adolescents completed pen and paper versions of the questionnaire and/or scales assessing social desirability, self-reported physical activity, and physical activity self-efficacy. An expert panel review, cognitive interviews, and a pilot study (n = 129) established content validity. Construct, concurrent, and predictive validity were also established (n = 520 youth). PAPSIA is a promising measure for assessing youth physical activity problem-solving ability. Future research will assess its validity with objectively measured physical activity.
New Protocol for Submaximal and Peak Exercise Values for Children and Adolescents: The Muscatine Study
Authors: Golden Jane C. , Janz Kathleen F. , Clarke William R. , Mahoney Larry T.
Published: August 2016

This paper demonstrates the reliability, validity, and practical applications of a unique protocol developed to obtain both submaximal steady-state and peak exercise responses in the same test in children and adolescents. The study examined exercise efficiency, cardiovascular fitness, and cardiovascular responses in 237 children, ages 7 to 17, during exercise stress on a cycle ergometer. The graded exercise test was continuous, consisting of three steady-state submaximal stages followed by 30-sec ramp stages to obtain peak values. Intraclass correlation coefficients ranged from r=0.69 to r=0.99, with no significant mean difference for any test parameter. Mean peak heart rate, peak VO2, and 84% of the respiratory exchange ratio (RER) values equal to or greater than 1.1 were comparable to other reported values. The validity for the protocol is substantiated by the results showing normal linear exercise responses, nonsignificant mean difference between the last two 30-sec periods, normal mean peak heart rate and VO2 values, and high mean peak RER values. The protocol is practical, as demonstrated by an optimal test duration and the ability to obtain valid submaximal and peak exercise data in the same test in subjects of varying ages and body size.
Adjustment of 1-Mile Run/Walk Test Scores for Skinfold Thickness in Youth
Authors: Cureton Kirk J. , Baumgartner Ted A. , McManis Beth G.
Published: August 2016

The purposes of this study were (a) to describe the relation of 1-mile run/walk time (MRWT) to skinfold thickness measures in a national probability sample of students 8 to 18 years of age (NCYFS I and II, n = 11,123) and (b) to evaluate the impact of adjusting MRWT scores for the effect of skinfold thickness on the classification of scores using percentile ranks and criterion referenced standards (CRS). MRWT was significantly related to the sum of subscapular and triceps skinfolds in all age-gender groups. In 12-year-olds, MRWT scores adjusted for sum of skinfolds by regression analysis resulted in individual percentile ranks that differed by more than 10 from percentile ranks of unadjusted scores in 29% of girls and 39% of boys, and altered classifications on the Fitnessgram and AAHPERD mile run/walk time CRS in 11-14% of boys and girls. It is concluded that the relation between MRWT and skinfold thickness is strong enough, and the impact of adjusting MRWT scores for skinfold thickness sufficient, to justify using adjusted scores for classification of cardiorespiratory capacity as part of the assessment of health related physical fitness in youth. Additional research is needed to cross-validate the equations developed in this study.
The Physical Activity Patterns of Northern Irish Schoolchildren Ages 11–16 Years
Authors: Riddoch Chris , Mahoney Craig , Murphy Niamh , Boreham Colin , Cran Gordon
Published: August 2016

The aim of this study was to provide objective data on the cardiopulmonary fitness and physical activity patterns of Northern Irish postprimary schoolchildren. Forty-five children (23 boys, 22 girls), ages 11-16 years, took part in this study. Each child performed a laboratory test of peak aerobic power (PVO2) and had his/her heart rate monitored for up to 4 school days. The mean values of PVO2 in both boys and girls were in keeping with previous literature. No significant difference was observed between boys and girls in terms of total activity (>50% PVO2), but boys engaged in significantly more vigorous activity (>70% PVO2 than girls did (p<0.05). Younger boys engaged in significantly more vigorous activity than both older boys (p<0.01) and younger girls (p<0.05). A significant negative correlation was found between age and total activity for boys (r= −0.476, p<0.05), but not for girls (r= -0.173, n.s.). The surprisingly low levels of physical activity on the part of older children of both sexes are a cause for concern.
A Developmental Analysis of Children’s Self-Ability Judgments in the Physical Domain
Authors: Horn Thelma S. , Weiss Maureen R.
Published: August 2016

This study examined developmental differences in children’s judgments of their physical competence. Two questionnaires were administered to 134 children, ranging in age from 8 to 13 years, to measure their perceptions of competence and the criteria they use to evaluate that competence. In addition, children’s actual physical competence was assessed through teacher evaluation. Univariate and multivariate analyses of the data revealed three major findings. First, the accuracy with which children judge their competence does increase with age. Second, the criteria children use to assess their competence is also age-dependent, with younger children showing greater preference for adult feedback and older children showing greater preference for peer comparison. Third, the criteria children use in competency judgments was found to be directly related to the accuracy of such judgments. The results of this study demonstrated the existence of developmental patterns with respect to children’s judgments of their physical competence.
An Examination of Efficiency during Walking in Children and Adults
Authors: Ebbeling Christine J. , Hamill Joseph , Freedson Patty S. , Rowland Thomas W.
Published: August 2016

This study compared metabolic, kinematic, and efficiency parameters in 10 boys and 10 men while walking at speeds of similar relative intensities. Heart rate and oxygen consumption were monitored throughout the exercise and a sagittal view of the subject was filmed for biomechanical analysis. Angles of the hip, knee, and ankle changed with an increase in walking speed. There were kinematic differences between children and adults at the hip and knee. Heart rate and oxygen consumption (ml•kg−1•min−1) were greater in the children. There were no significant differences between children and adults when VO2 was normalized by body surface area rather than body mass. The work done by the body was greater in the adults, whereas the energy used was greater in the children. Therefore the children appeared less efficient. The reasons for the efficiency difference are not well documented. Scaling effects may be involved and therefore should be taken into consideration when comparing children and adults.