The relationship among physical activity, motor competence and health-related fitness in 14-year-old adolescents

Systematic review of the relationships between objectively measured physical activity and health indicators in school-aged children and youth

Moderate-to-vigorous physical activity (MVPA) is essential for disease prevention and health promotion. Emerging evidence suggests other intensities of physical activity (PA), including light-intensity activity (LPA), may also be important, but there has been no rigorous evaluation of the evidence. The purpose of this systematic review was to examine the relationships between objectively measured PA (total and all intensities) and health indicators in school-aged children and youth. Online databases were searched for peer-reviewed studies that met the a priori inclusion criteria: population (apparently healthy, aged 5-17 years), intervention/exposure/comparator (volumes, durations, frequencies, intensities, and patterns of objectively measured PA), and outcome (body composition, cardiometabolic biomarkers, physical fitness, behavioural conduct/pro-social behaviour, cognition/academic achievement, quality of life/well-being, harms, bone health, motor skill development, psychological distress, self-esteem). Heterogeneity among studies precluded meta-analyses; narrative synthesis was conducted. A total of 162 studies were included (204 171 participants from 31 countries). Overall, total PA was favourably associated with physical, psychological/social, and cognitive health indicators. Relationships were more consistent and robust for higher (e.g., MVPA) versus lower (e.g., LPA) intensity PA. All patterns of activity (sporadic, bouts, continuous) provided benefit. LPA was favourably associated with cardiometabolic biomarkers; data were scarce for other outcomes. These findings continue to support the importance of at least 60 min/day of MVPA for disease prevention and health promotion in children and youth, but also highlight the potential benefits of LPA and total PA. All intensities of PA should be considered in future work aimed at better elucidating the health benefits of PA in children and youth.

Comparison of Health Outcomes Among Children with Different Levels of Motor Competence

While evidence suggests that children with the developmental coordination disorder (DCD) have worse health outcomes than their typically developing peers, it remains unclear whether children with low motor competence but without DCD are also characterized by worse health outcomes than those with average motor competence. The main purpose of this study was to compare health outcomes between children with low motor competence without DCD and those with average motor competence.

The total of 127 children aged 12–14 years were recruited. Motor competence, physical activity, flexibility, and muscular strength/endurance were assessed with, respectively, the Körperkoordinationstest für Kinder, a validated self-administered questionnaire, sit-and-reach, and sit-up 60s tests. Skinfold thickness was measured to assess the children’s adiposity. Multivariate analysis of variance, Kruskal-Wallis, and Mann-Whitney tests were performed.

Children with average motor competence had lower body fat percentage and higher levels of physical activity and muscular strength/endurance than the groups with low (

Our findings suggest that children with low motor competence without DCD have worse health outcomes than their peers with average motor competence. We suggest that both the development of motor competence and improvement of health outcomes should be targeted during childhood and adolescence by health professionals.

Development and evaluation of the psychometric properties of the Adolescent Motor Competence Questionnaire (AMCQ) for Adolescents

BACKGROUND

There are no valid and reliable self-report measures designed to identify level of motor competence and suspected motor difficulties among 12-18year old adolescents.

AIM

This paper reports the development and evaluation of a self-report questionnaire (Adolescent Motor Competence Questionnaire; AMCQ) to address this need.

METHOD

The project proceeded in 3 phases; (A) item development, (B) content evaluation, and (C) examination of reliability and validity of the final questionnaire. Each phase was informed by criteria A and B in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), comments from a sample of 10 adolescents aged between 12 and 18 years with a range of movement skills, key informants and international experts. A convenience sample of 38 adolescents completed the final version of the AMCQ. The McCarron Assessment of Neuromuscular Development (MAND) was used to investigate concurrent validity.

RESULTS

The final version of the AMCQ comprised 26 items scored using a 4 point Likert scale with a maximum score of 104. Analyses revealed the questionnaire has an acceptable internal consistency (0.902) and 7day test-retest reliability (0.956). A moderate positive correlation between the AMCQ and the MAND of 0.491 (p<0.002) provides some evidence of concurrent validity.

CONCLUSION

The development of the AMCQ was exploratory in nature and has the potential to be a reliable and valid tool for measuring motor competence in Australian adolescents.

Flexibility is associated with motor competence in schoolchildren

Available data on the associations between motor competence (MC) and flexibility are limited and result inconclusive. This study aims to examine the relationship between flexibility and MC in children. The sample comprised 596 Portuguese children (47.1% girls) aged 9.7 ± 0.6 years. Motor competence was evaluated with the body coordination test, Körperkoordination Test für Kinder. Cardiorespiratory fitness (20-m shuttle run), muscular strength (curl-up and push-up tests), and flexibility (back-saver sit and reach and trunk-lift tests) were evaluated using the Fitnessgram Test Battery. Z-scores by age and gender for the physical fitness tests were constructed. Analysis of variance and regression analysis were performed. Participants in the healthy zone groups of both flexibility tests exhibited significantly better scores of MC than the participants under the healthy zone (P < 0.001). Back-saver sit and reach and trunk-lift Z-scores, either individually or as a sum, were significant predictors of MC (P < 0.05 for all) after adjustments for the other physical fitness components, age, body mass index, and socioeconomic status, in both genders. Our findings highlight the importance of promoting and developing flexibility, as well as the other health-related physical fitness components in schoolchildren to reach adequate levels of MC.

The relationship between motor skills, ADHD symptoms, and childhood body weight

BACKGROUND

Research has suggested an important association between motor proficiency and overweight/obesity. Many children with motor difficulties experience ADHD symptoms which have also been linked with overweight/obesity. Previous research has not considered both ADHD and motor performance when investigating their relationship with overweight/obesity.

AIMS

To investigate the relationships between motor performance, ADHD symptoms, and overweight/obesity in children.

METHODS AND PROCEDURES

A cross-sectional study was conducted involving189 children aged six to 10 years. Symptoms of ADHD were identified using the SNAP-IV rating scale. Motor impairment (MI) was identified using the Movement Battery Assessment for Children-2. Body composition was estimated from the Body Mass Index (BMI) based on World Health Organization child growth standards.

OUTCOMES AND RESULTS

Balance was the only motor skill associated with BMI even after controlling for gender and ADHD. Group comparisons revealed that the proportion of overweight ADHD children was significantly less than the proportion of overweight control children and overweight MI children; the proportion of underweight ADHD children was significantly greater than the proportion of underweight MI children.

CONCLUSIONS AND IMPLICATIONS

The results highlight the importance of taking into consideration both ADHD symptoms and motor difficulties in the assessment and intervention of physical health outcomes in children with ADHD and/or movement problems.

Motor Development and Physical Activity: A Longitudinal Discordant Twin-Pair Study

INTRODUCTION

Previous longitudinal research suggests that motor proficiency in early life predicts physical activity in adulthood. Familial effects including genetic and environmental factors could explain the association, but no long-term follow-up studies have taken into account potential confounding by genetic and social family background. The present twin study investigated whether childhood motor skill development is associated with leisure-time physical activity levels in adulthood independent of family background.

METHODS

Altogether, 1550 twin pairs from the FinnTwin12 study and 1752 twin pairs from the FinnTwin16 study were included in the analysis. Childhood motor development was assessed by the parents' report of whether one of the co-twins had been ahead of the other in different indicators of motor skill development in childhood. Leisure-time physical activity (MET·h·d) was self-reported by the twins in young adulthood and adulthood. Statistical analyses included conditional and ordinary linear regression models within twin pairs.

RESULTS

Using all activity-discordant twin pairs, the within-pair difference in a sum score of motor development in childhood predicted the within-pair difference in the leisure-time physical activity level in young adulthood (P < 0.001). Within specific motor development indicators, learning to stand unaided earlier in infancy predicted higher leisure-time MET values in young adulthood statistically significantly in both samples (FinnTwin12, P = 0.02; and FinnTwin16, P = 0.001) and also in the pooled data set of the FinnTwin12 and FinnTwin16 studies (P < 0.001). Having been more agile than the co-twin as a child predicted higher leisure-time MET values up to adulthood (P = 0.03).

CONCLUSIONS

More advanced childhood motor development is associated with higher leisure-time MET values in young adulthood at least partly independent of family background in both men and women.

Hypothalamic-pituitary-adrenal axis activity under resting conditions and cardiovascular risk factors in adolescents

BACKGROUND

Activation of the hypothalamic-pituitary-adrenal (HPA) axis has been associated with higher levels of cardiovascular (CVD) risk factors in adults. This study aimed to assess the relation between measures of HPA axis activity under resting conditions and CVD risk factors in a general population of adolescents at 17 years.

METHODS

A total of 1134 adolescents from the Western Australian Pregnancy Cohort (Raine) Study had phenotypic and socio-demographic data. The associations between HPA axis measures (plasma ACTH, total cortisol, calculated free cortisol, corticosteroid binding globulin (CBG), and salivary cortisol) and a range of cardiovascular risk factors were examined using multivariable linear regression models, with adjustment for gender, adiposity, birth weight, gestational age, and socio-behavioural factors.

RESULTS

Plasma total cortisol was positively associated with systolic blood pressure (SBP) (p=0.011), total cholesterol, HDL-cholesterol, and triglycerides (all p<0.001), and hs-CRP (p=0.047). Salivary cortisol was associated positively with HDL-C (p=0.033) and negatively with LDL-cholesterol (p=0.016); plasma calculated free cortisol was positively associated with triglycerides (p=0.006); plasma CBG was positively associated with total cholesterol and HDL-cholesterol (both p<0.001), LDL-cholesterol (p=0.022), and hs-CRP (p=0.001). After correction for multiple comparisons, significant associations remained for total cortisol with total cholesterol, HDL-C, and triglycerides; for calculated free cortisol with triglycerides; and for CBG with HDL-C, total cholesterol, and hs-CRP. Plasma ACTH was not associated with any cardiovascular risk factor. There was no association between BMI and any measure of HPA axis activity.

CONCLUSION

In an adolescent population, HPA axis measures under resting conditions are associated with a range of CVD risk factors. Clarification of the mechanisms underlying these associations in adolescence would be an important step in understanding the evolution of adult CVD.

Physical Activity, Affect, and Cognition in Children With Symptoms of ADHD

OBJECTIVE

To examine the role of physical activity in determining the affect and executive functioning of children with symptoms of ADHD.

METHOD

In Study 1, the association between physical activity and affect in the daily lives of children with varying degrees of hyperactivity was examined. In Study 2, children with ADHD were randomly assigned a physical activity or a sedentary task before working on a task requiring executive control.

RESULTS

Lack of physical activity was shown to relate to depressed affect, more strongly in participants with severe hyperactivity symptoms (Study 1). The physically active participants showed improved executive functioning after only 5 min of vigorous activity; the sedentary control participants showed no improvement (Study 2).

CONCLUSION

These results indicate that interventions to increase the level of physical activity in children with and without ADHD might improve affect and executive functioning.

THE RELATIONSHIP BETWEEN MOTOR COMPETENCE AND PHYSICAL FITNESS IS WEAKER IN THE 15-16 YR. ADOLESCENT AGE GROUP THAN IN YOUNGER AGE GROUPS (4-5 YR. AND 11-12 YR.)

Developing motor competence and physical fitness can affect the maintenance of a sufficient level of physical activity in children and adolescents. This study assesses the relationship between motor competence and physical fitness from childhood through early adolescence. A cross-sectional sample of 194 participants from 4 to 16 years old were divided into three groups; 4-6 yr. (n=42, M age=5.2, SD 0.6), 11-12 yr. (n=58, M age=12.4, SD=0.3), and 15-16 yr. (n=94, M age=15.9, SD=0.4). To assess motor competence, each child completed the Movement Assessment Battery for Children (MABC). To measure physical fitness, three tasks (strength, speed, and endurance) were selected from the Test of Physical Fitness (TPF). To analyze the significance of the difference between the correlation coefficient in the three age groups (samples) (4-6, 11-12, and 15-16 yr.), Fischer r-to-z transformation was used. The correlation (Pearson's) between motor competence and physical fitness in the age groups was statistically higher for the youngest age groups (4-6 and 11-12 yr.) and the adolescent group (age 15-16). The differences between the two youngest age groups were not statistically significant. The results demonstrate that the correlation between motor competence and physical fitness decreases with age.

Identification of a dietary pattern prospectively associated with bone mass in Australian young adults

BACKGROUND

Relatively little is known about the relations between dietary patterns and bone health in adolescence, which is a period of substantial bone mass accrual.

OBJECTIVES

We derived dietary patterns that were hypothesized to be related to bone health on the basis of their protein, calcium, and potassium contents and investigated their prospective associations with bone mineral density (BMD), bone area, and bone mineral content (BMC) in a cohort of young adults.

DESIGN

The study included 1024 young adults born to mothers who were participating in the Western Australian Pregnancy Cohort (Raine) Study. Dietary information was obtained from food-frequency questionnaires at 14 and 17 y of age. Dietary patterns were characterized according to protein, calcium, and potassium intakes with the use of reduced-rank regression. BMD, bone area, and BMC were estimated with the use of a total body dual-energy X-ray absorptiometry scan at 20 y of age.

RESULTS

We identified 2 major dietary patterns. The first pattern was positively correlated with intakes of protein, calcium, and potassium and had high factor loadings for low-fat dairy products, whole grains, and vegetables. The second pattern was positively correlated with protein intake but negatively correlated with intakes of calcium and potassium and had high factor loadings for meat, poultry, fish, and eggs. After adjustment for anthropometric, sociodemographic, and lifestyle factors, a higher z score for the first pattern at 14 y of age was positively associated with BMD and BMC at 20 y of age [differences: 8.6 mg/cm(2) (95% CI: 3.0, 14.1 mg/cm(2)) and 21.9 g (95% CI: 6.5, 37.3 g), respectively, per SD increase in z score]. The z score for this same pattern at 17 y of age was not associated with bone outcomes at 20 y of age. The second pattern at 14 or 17 y of age was not associated with BMD, BMC, or bone area.

CONCLUSIONS

A dietary pattern characterized by high intakes of protein, calcium, and potassium in midadolescence was associated with higher BMD and BMC at 20 y of age. Our results indicate that high consumption of low-fat dairy products, whole grains, and vegetables in adolescence are associated with beneficial effects on bone development.

Correlates of physical activity behaviours in young Iranian girls

BACKGROUND

This study examined the relationship among motor skill competence, perceived motor competence (PMC), health-related physical fitness and physical activity in 8-9-year-old Iranian girls (n = 352).

METHODS

Locomotor and object control motor skill competence was assessed using the Test of Gross Motor Development - 2nd edition. PMC was assessed using the Physical Ability subscale of Marsh's Self-Description Questionnaire-1. Health-related physical fitness was measured with body mass index, the 600 yard run/walk, curl-ups, push-ups, and back-saver sit and reach tests. Children's physical activity was assessed using the Physical Activity Questionnaire for Older Children.

RESULTS

Regression analysis revealed that locomotor proficiency, aerobic fitness and PMC accounted for 56% (P < .001) of variance associated with moderate-to-vigorous physical activity.

CONCLUSION

The findings warrant future investigations that examine interventions that focus on motor skill and perceived competence along with aerobic fitness to promote physical activity in girls.

Two-year longitudinal health-related fitness, anthropometry and body composition status amongst adolescents in Tlokwe Municipality: The PAHL Study

AIM

To evaluate a two-year longitudinal development of health-related fitness, anthropometry and body composition status amongst adolescents in Tlokwe Municipality, Potchefstroom, South Africa.

SETTING

A total of 283 high-school learners (111 boys and 172 girls) of ages 14 and 15 years who were part of the ongoing Physical Activity and Health Longitudinal Study (PAHLS) participated in the study. For the purpose of the present study, data collected for 2011 and 2012 for anthropometric, body composition and health-related physical fitness were used.

RESULTS

Body mass index (BMI) classification of boys and girls for 2011 and 2012 showed that 24.3% of them were underweight compared with 21% in 2012. In 2011, 50% of boys and girls had normal bodyweight compared with 52% in 2012, whilst 25.5% of the total group of participants were overweight compared with 27% in 2012. Both boys and girls showed significant increases of 5.9% in body fat (BF) and 3.2 kg in body weight over two years' measurements, respectively. Regarding health-related fitness (i.e BAH), boys showed an increase of 14.8 seconds whilst girls gained 9.6 seconds. Significant decreases were found for sit-ups in both boys and girls. A significant VO2max increase of 2.9 mL/kg/min. was found in boys over the time period. A non-significant decrease of -0.5 mL/kg/min. was observed in girls. Regression coefficients showed that changes in BMI were inversely associated with those in health-related physical fitness. The changes in percentage BF were negatively associated with standing broad jump (SBJ), bent arm hang (BAH) and VO2 max in both boys and girls. A low significant positive association was found between changes in waist-to-height ratio (WHtR) and SBJ in both genders, whilst inverse low associations were found between WHtR and BAH in girls and for VO2max in both genders.

CONCLUSION

Changes in BMI, %BF and WHtR were negatively associated with strength and running performances in the participating children. The relative increase in overweight, especially in girls, negatively affected their endurance running and static strength performances. The health implications of the observed findings are discussed and recommendations offered for physical activity intervention in school physical education (PE) programmes.

The health benefits of muscular fitness for children and adolescents: a systematic review and meta-analysis

BACKGROUND

Physical fitness during childhood and adolescence has been identified as an important determinant of current and future health status. While research has traditionally focused on the association between cardio-respiratory fitness and health outcomes, the association between muscular fitness (MF) and health status has recently received increased attention.

OBJECTIVE

The aim of this systematic review and meta-analysis was to evaluate the potential physiological and psychological benefits associated with MF among children and adolescents.

METHODS

A systematic search of six electronic databases (PubMed, SPORTDiscus, Scopus, EMBASE, PsycINFO and OVID MEDLINE) was performed on the 20th May, 2013. Cross-sectional, longitudinal and experimental studies that quantitatively examined the association between MF and potential health benefits among children and adolescents were included. The search yielded 110 eligible studies, encompassing six health outcomes (i.e., adiposity, bone health, cardiovascular disease [CVD] and metabolic risk factors, musculoskeletal pain, psychological health and cognitive ability). The percentage of studies reporting statistically significant associations between MF and the outcome of interest was used to determine the strength of the evidence for an association and additional coding was conducted to account for risk of bias. Meta-analyses were also performed to determine the pooled effect size if there were at least three studies providing standardised coefficients.

RESULTS

Strong evidence was found for an inverse association between MF and total and central adiposity, and CVD and metabolic risk factors. The pooled effect size for the relationship between MF and adiposity was r = -0.25 (95% CI -0.41 to -0.08). Strong evidence was also found for a positive association between MF and bone health and self-esteem. The pooled effect size for the relationship between MF and perceived sports competence was r = 0.39 (95% CI 0.34-0.45). The evidence for an association between MF and musculoskeletal pain and cognitive ability was inconsistent/uncertain. Where evidence of an association was found, the associations were generally low to moderate.

CONCLUSION

The findings of this review highlight the importance of developing MF in youth for a number of health-related benefits.

Mediating effects of resistance training skill competency on health-related fitness and physical activity: the ATLAS cluster randomised controlled trial

The purpose of this study was to examine the mediating effect of resistance training skill competency on percentage of body fat, muscular fitness and physical activity among a sample of adolescent boys participating in a school-based obesity prevention intervention. Participants were 361 adolescent boys taking part in the Active Teen Leaders Avoiding Screen-time (ATLAS) cluster randomised controlled trial: a school-based program targeting the health behaviours of economically disadvantaged adolescent males considered "at-risk" of obesity. Body fat percentage (bioelectrical impedance), muscular fitness (hand grip dynamometry and push-ups), physical activity (accelerometry) and resistance training skill competency were assessed at baseline and post-intervention (i.e., 8 months). Three separate multi-level mediation models were analysed to investigate the potential mediating effects of resistance training skill competency on each of the study outcomes using a product-of-coefficients test. Analyses followed the intention-to-treat principle. The intervention had a significant impact on the resistance training skill competency of the boys, and improvements in skill competency significantly mediated the effect of the intervention on percentage of body fat and the combined muscular fitness score. No significant mediated effects were found for physical activity. Improving resistance training skill competency may be an effective strategy for achieving improvements in body composition and muscular fitness in adolescent boys.

Development and validation of a model of motor competence in children and adolescents

OBJECTIVES

This study was aimed at developing a quantitative model to evaluate motor competence (MC) in children and adolescents, to be applicable in research, education, and clinical contexts.

DESIGN

Cross-sectional.

METHODS

A total of 584 children (boys n=300) with ages between 6 and 14 years were assessed using nine well known quantitative motor tasks, divided into three major components (stability, locomotor and manipulative). Structural equation modelling through EQS 6.1 was used to find the best model for representing the structural and measurement validity of MC.

RESULTS

The final MC model was composed by three latent factors closely related with each other. Each factor was best represented by two of the initial three motor tasks chosen. The model was shown to give a very good overall fit (χ(2)=12.04, p=.061; NFI=.982; CFI=.991; RMSEA=.059).

CONCLUSIONS

MC can be parsimoniously represented by six quantitative motor tasks, grouped into three interrelated factors. The developed model was shown to be robust when applied to different samples, demonstrating a good structural and measurement reliability. The use of a quantitative protocol with few, simple to administer and well known, motor tasks, is an important advantage of this model, since it can be used in several contexts with different objectives. We find it especially beneficial for physical educations teachers who have to regularly assess their students.

Identification of a dietary pattern associated with greater cardiometabolic risk in adolescence

BACKGROUND AND AIMS

Energy dense, high fat, low fibre diets may contribute to obesity in young people, however their relationships with other cardiometabolic risk factors are unclear. We examined associations between an 'energy-dense, high-fat and low-fibre' dietary pattern (DP) and cardiometabolic risk factors, and the tracking of this DP in adolescence.

METHODS AND RESULTS

Data was sourced from participants in the Western Australian Pregnancy (Raine) Cohort Study. At 14 and 17 y, dietary intake, anthropometric and biochemical data were measured and z-scores for an 'energy dense, high fat and low fibre' DP were estimated using reduced rank regression (RRR). Associations between DP z-scores and cardiometabolic risk factors were examined using regression models. Tracking of DP z-scores was assessed using Pearson's correlation coefficient. A 1 SD unit increase in DP z-score between 14 and 17 y was associated with a 20% greater odds of high metabolic risk (95% CI: 1.01, 1.41) and a 0.04 mmol/L higher fasting glucose in boys (95% CI: 0.01, 0.08); a 28% greater odds of a high-waist circumference (95% CI: 1.00, 1.63) in girls. An increase of 3% and 4% was observed for insulin and HOMA (95% CI: 1%, 7%), respectively, in boys and girls, for every 1 SD increase in DP z-score and independently of BMI. The DP showed moderate tracking between 14 and 17 y of age (r = 0.51 for boys, r = 0.45 for girls).

CONCLUSION

An 'energy dense, high fat, low fibre' DP is positively associated with cardiometabolic risk factors and tends to persist throughout adolescence.

The relationship between segmental coordination, agility and physical activity in adolescents

Motor competence (MC) may be related to youth physical activity (PA) level. In the last few years, MC has been studied as a possible determinant of children PA level, but has not been widely studied in adolescents. To analyze the relationship between MC and PA level 533 adolescents (271 men and 261 women) from the southeast of Spain were assessed. To register weekly PA was used the International Physical Activity Questionnaire (IPAQ) and for the MC, four coordination tests including throw and catch test, eye-hand and eye-foot coordination tests and agility circuit. Data were analyzed using ANOVA and binary logistic regression. The overall MC is consistently related with PA level. Eye-hand coordination test and the agility test define more accurately the tendency to high PA level. Programs to promote PA and focused on MC should be emphasized from early ages to adolescence.

A review of five tests to identify motor coordination difficulties in young adults

Difficulties with low motor competence in childhood and adolescence, such as that seen in Developmental Coordination Disorder (DCD), often persist into adulthood. Identification of DCD at all ages is particularly challenging and problematic because of the diversity of motor symptoms. Many tests of motor proficiency and impairment have been developed for children up to 12 years of age. Whilst identification of DCD is important during childhood, it is of equal importance to identify and monitor the impact of this impairment as an individual grows and develops. Currently there is no test specifically designed to support diagnosis and monitor change in the age range 16-30 years. In this article we review five tests that have been used to assess motor competence among young adults (Bruininks-Oseretsky Test of Motor Proficiency-2, McCarron Assessment of Neuromuscular Development, Movement Assessment Battery for Children-2, Tufts Assessment of Motor Performance and the Zurich Neuromotor Assessment). Key issues relevant to testing motor skills in older populations, such as the inclusion of age appropriate skills, are explored. While the BOT-2 provided the most evidence for valid and reliable measurement of Criterion A of the diagnostic criteria for DCD among this age group, no test adequately evaluated Criterion B. Further evaluation of motor skill assessment among the young adult population is needed.

Peripheral quantitative computed tomography (pQCT) reveals low bone mineral density in adolescents with motor difficulties

This is the first reported study to describe local bone mineral density, assess parameters of fracture risk and report history of fractures in adolescents with motor difficulties. Motor difficulties evidenced by poor coordination in adolescence should be considered a new risk factor for below-average bone strength and structure and fracture risk.

INTRODUCTION

Adolescents with motor difficulties are characterised by poor coordination and low levels of physical activity and fitness. It is possible these deficits translate into below-average bone strength and structure. The objectives of this study were to describe local bone mineral density (BMD), assess parameters of fracture risk (stress-strain index, SSI) and report history of fractures in this group.

METHODS

Thirty-three adolescents (13 females), mean age of 14.3 (SD = 1.5) years, with motor difficulties underwent peripheral quantitative computed tomography (pQCT) measurements at proximal (66 %) and distal (4 %) sites of the non-dominant radius (R4 and R66) and tibia (T4 and T66). One sample t test was used to compare Z-scores for total BMD, trabecular density, cortical density and stress strain index (SSI) against standardized norms.

RESULTS

Significant differences were present at R4 total density mean Z-score = -0.85 (SD = 0.7, p < 0.001), R66 cortical density mean Z-score = -0.74 (SD = 1.97, p = 0.038), R66 SSI mean Z-score = -1.00 (SD = 1.08, p < 0.001) and T66 SSI mean Z-score = -0.70 (SD = 1.15, p < 0.001). There was a higher incidence of fractures (26.9 %) compared to the normal population (3-9 %).

CONCLUSIONS

Motor difficulties in adolescence should be considered a risk factor for below-average bone strength and structure and fracture risk. Strategies are needed to improve bone health in this high-risk-group.

Exercise can improve physical self perceptions in adolescents with low motor competence

Adolescents with low motor competence have diminished perceptions of their physical self and tend to avoid physical activities. This study examined the outcomes of an exercise intervention that focused on improving aerobic fitness, strength, and self-perceptions in the physical domain in adolescents with poor motor coordination. The sample included 35 adolescents with low motor competence, comprising boys (n = 25) and girls (n = 10) ranging in age from 13 to 17 years, who attended two sessions per week in the 13 week exercise intervention study (AMP it up). Physical self-perceptions were measured before and after the intervention using the Physical Self Perception Profile and Perceived Importance Profile. Significant improvements in perceived Physical Condition, Attractive Body and Physical Strength sub domain scores were identified between pre and post-test. Adjusting for age, gender, BMI and attendance, regression analyses revealed that Attractive Body was the strongest predictor of Physical Self Worth at pre-test, joined by Physical Condition at post-test. This exercise intervention had a positive impact on adolescent physical self-perceptions, in particular males, with improvements in those sub domains specifically related to the exercise program. Changes in specific aspects of Physical Self Worth can be facilitated by exercise interventions, after a relatively short period of time, in adolescents with poor motor coordination.

Meditation and mindfulness in clinical practice

This article describes the various forms of meditation and provides an overview of research using these techniques for children, adolescents, and their families. The most researched techniques in children and adolescents are mindfulness-based stress reduction, mindfulness-based cognitive therapy, yoga meditation, transcendental meditation, mind-body techniques (meditation, relaxation), and body-mind techniques (yoga poses, tai chi movements). Current data are suggestive of a possible value of meditation and mindfulness techniques for treating symptomatic anxiety, depression, and pain in youth. Clinicians must be properly trained before using these techniques.

The effects of aquatic exercise on body composition, physical fitness, and vascular compliance of obese elementary students

The purpose of this study was to investigate the effects of aquatic exercise on body composition, physical fitness, and vascular compliance of obese elementary school students. For the purpose of this study, 20 obese elementary students were selected as subjects. The subjects were then divided into two groups: the swimming group (n= 10) and the control group (n= 10). The subjects were asked to exercise for 60 minutes a day, 3 times a week for 12 weeks with an exercise intensity of 50-70% HRmax. The following results were achieved: first, in terms of body composition, both body fat percentage and fat-free mass showed significant differences within the swimming group. There were also significant differences again in the posttest of difference between the two groups. Second, in terms of changes in physical fitness, there were, again, no significant changes in muscular strength between the two groups. However, muscular endurance, flexibility, and cardiopulmonary endurance showed significant differences in the swimming group's test for difference within groups. Significant differences in both groups for the posttest of differences between groups were also seen. Third, in terms of vascular compliance, there was a significant increase in the right leg for the swimming groups' test of difference within groups, as well as in the posttest of difference between groups.

Physical fitness in children with developmental coordination disorder: measurement matters

Children with Developmental Coordination Disorder (DCD) experience considerable difficulties coordinating and controlling their body movements during functional motor tasks. Thus, it is not surprising that children with DCD do not perform well on tests of physical fitness. The aim of this study was to determine whether deficits in motor coordination influence the ability of children with DCD to perform adequately on physical fitness tests. A case-control study design was used to compare the performance of children with DCD (n=70, 36 boys, mean age=8 y 1 mo) and Typically Developing (TD) children (n=70, 35 boys, mean age=7 y 9 mo) on measures of isometric strength (hand-held dynamometry), functional strength, i.e. explosive power and muscular endurance (Functional Strength Measurement), aerobic capacity (20 m Shuttle Run Test) and anaerobic muscle capacity, i.e. muscle power (Muscle Power Sprint Test). Results show that children with DCD were able to generate similar isometric forces compared to TD children in isometric break tests, but were significantly weaker in three-point grip strength. Performance on functional strength items requiring more isolated explosive movement of the upper extremities, showed no significant difference between groups while items requiring muscle endurance (repetitions in 30s) and items requiring whole body explosive movement were all significantly different. Aerobic capacity was lower for children with DCD whereas anaerobic performance during the sprint test was not. Our findings suggest that poor physical fitness performance in children with DCD may be partly due to poor timing and coordination of repetitive movements.

Physical fitness, motor skill, and physical activity relationships in grade 4 to 6 children

The present study sought to quantify the relationships among physical activity (PA), health-related fitness, and motor skill in children (grades 4 to 6), and to determine whether specific tests of fitness or motor skill are independently associated with objectively measured PA level. Four hundred and ninety-one students (56.4% female) wore a Digi-Walker pedometer for 7 consecutive days. Standardized protocols were used to assess health-related fitness (body mass index percentile, waist circumference, 20-m shuttle run, plank, handgrip, and trunk flexibility). Motor skill was evaluated using a validated obstacle course. Pearson correlations (with Holm adjustments for multiple comparisons) initially assessed associations among PA, health-related fitness, and motor skill. Multi-variable linear regression was used to determine which factors were significantly associated with daily step counts, while adjusting for gender, age, testing season, and socioeconomic status. Step counts were significantly correlated with predicted aerobic power (r = 0.30), obstacle course time (r = −0.27), obstacle course score (r = 0.20), plank isometric torso endurance (r = 0.16), and handgrip strength (r = 0.12), but not with waist circumference (r = −0.10), trunk flexibility (r = 0.10), or overweight status (ρ = −0.06). In the multi-variable model, predicted aerobic power, obstacle course time, testing season, gender, and the predicted aerobic power by gender interaction were significantly associated with step counts, explaining 16.4% of the variance. Specifically, the relationship between predicted aerobic power and step counts was stronger in girls. These findings suggest that aerobic fitness and motor skill are independently associated with children’s PA. Future longitudinal studies should evaluate whether interventions to enhance aerobic fitness and motor skill could enhance daily PA among children of this age.

Lower fructose intake may help protect against development of nonalcoholic fatty liver in adolescents with obesity

OBJECTIVES

Although obesity is a major risk factor for nonalcoholic fatty liver (NAFL), not all individuals with obesity develop the condition, suggesting that other factors such as diet may also contribute to NAFL development. We evaluated associations between fructose and total sugar intake and subsequent diagnosis of NAFL in adolescents with obesity and without obesity in a population-based cohort.

METHODS

Adolescents participating in the Western Australian Pregnancy Cohort (Raine) Study completed 3-day food records and body mass index measurement at age 14 years. At age 17 years, participants underwent abdominal ultrasound to determine NAFL status. Multivariable logistic regression models were used to analyse associations between energy-adjusted fructose and total sugar intake and NAFL status. Food diaries and liver assessments were completed for 592 adolescents.

RESULTS

The prevalence of NAFL at age 17 was 12.8% for the total group and 50% for adolescents with obesity. Fructose intake did not significantly differ between adolescents with or without NAFL in our cohort as a whole. Among adolescents with obesity, those without NAFL had significantly lower energy-adjusted fructose intake at age 14 years compared with those with NAFL (mean ± standard deviation [SD] 38.8 ± 19.8 g/day, vs 55.7 ± 14.4 g/day, P = 0.02). Energy-adjusted fructose intake was independently associated with NAFL in adolescents with obesity (OR [odds ratio] 1.09, 95% CI 1.01-1.19, P = 0.03) after the adjustment for confounding factors. Energy-adjusted total sugar intake showed less significance (OR 1.03, 95% CI 0.999-1.07, P = 0.06). No significant associations were observed in other body mass index categories.

CONCLUSIONS

Lower fructose consumption in adolescents with obesity at 14 years is associated with a decreased risk of NAFL at 17 years. Fructose rather than overall sugar intake may be more physiologically relevant in this association.

Gender and the active smoking and high-sensitivity C-reactive protein relation in late adolescence

C-reactive protein (CRP), smoking, and oral contraceptive (OC) use are associated with CVD risk in adults. This study examines the effect of smoking on high-sensitivity CRP (hs-CRP) levels, and the interactive effects of sex and OC use on this relationship in an adolescent cohort. A total of 1,050 adolescents (mean age 17 ± 0.25 years) from the Western Australian Pregnancy Cohort (Raine) Study had anthropometric, lifestyle, and metabolic measures recorded. The association between smoking status and log-transformed hs-CRP was analyzed using multivariable Tobit linear regression models, with adjustment for adiposity, lifestyle, and early-life confounders. A three-level variable (girls not using OCs, girls using OCs, and boys) was employed to assess the interactive effects of sex, OC use, and smoking. Smoking associated with higher hs-CRP levels in girls not using OCs (b = 0.571; P = 0.001), but not in girls using OCs (b = -0.117; P = 0.598) or in boys (b = 0.183; P = 0.2). OC use in nonsmoking girls was the strongest factor associated with higher hs-CRP levels (b = 1.189; P < 0.001). This study has demonstrated a more robust effect of smoking on hs-CRP levels in girls not using OCs compared with boys. The findings may explain why CVD risk conferred by smoking is higher in women than in men.

Motor competence and physical fitness in adolescents

PURPOSE

In this study we examined the relationship between physical fitness and motor competence in adolescents aged 15 to 16 years.

METHODS

A sample of 94 adolescents participated in the study. To test motor competence, the Movement Assessment Battery for Children-2 was used. Physical fitness was assessed using the following test items: standing broad jump, 20-m dash, reduced Cooper test, and sit-and-reach test.

RESULTS

The results revealed a significant but weak relationship (0.248) between motor competence and physical fitness for the whole sample. More specifically, the correlation between the 2 variables was significant for girls (0.353) but not for boys (0.248).

CONCLUSIONS

The relatively weak relationship between motor competence and physical fitness suggests that motor competence might not be critical in adolescents to maintain their physical fitness.

A massa gorda de risco afeta a capacidade aeróbia de jovens adolescentes

OBJETIVO: Estudar o comportamento do sexo e os efeitos da idade e da massa gorda sobre a capacidade aeróbia de jovens adolescentes. MÉTODOS: Os 621 estudantes do ensino secundário participantes no estudo (14 aos 17 anos; feminino: n = 329, idade, 15,84 ± 0,92 anos; masculino: n = 292, idade, 15,82 ± 0,87 anos) foram avaliados em duas categorias: morfologia (altura, peso e % massa gorda - %MG) e aptidão física (capacidade aeróbia). As medições antropométricas foram realizadas de acordo com o protocolo descrito por Marfell-Jones e a %MG foi calculada por bioimpedância. A avaliação da capacidade aeróbia foi realizada com o teste aeróbio de corrida - PACER, e VO2máx relativo foi calculado utilizando a equação de Léger. Os resultados das avaliações foram classificados de acordo com os valores normativos das tabelas de referência da bateria de testes FITNESSGRAM® As técnicas estatísticas utilizadas foram: 1) cálculo de frequências; 2) teste t de Student para amostras independentes; e 3) ANOVA two-way seguida do teste post-hoc HSD de Bonferroni. RESULTADOS: 1) existem diferenças significativas entre sexos no que se refere à %MG e ao VO2máx; 2) durante a adolescência, o VO2máx estabiliza nos rapazes e sofre um declínio nas moças; 3) independentemente do sexo, a classe de %MG e a idade cronológica têm um efeito significativo sobre a capacidade aeróbia; e 4) em jovens adolescentes, com %MG de risco, a redução da %MG para níveis saudáveis parece resultar na melhoria da capacidade aeróbia. CONCLUSÃO: O impacto da %MG na capacidade aeróbia, reforça a importância da educação física escolar na promoção da saúde cardiovascular.

The role of content knowledge in conceptions of teaching effectiveness in physical education

Physical education teachers and the programs that prepare them find themselves in the early part of the 21st century in a public policy environment that differs significantly from that of the 20th century. This policy environment is grounded in an ideology that postulates that schools and teachers, rather than social forces, should be held responsible for academic outcomes, and in turn, economic success. For the first time, physical education teachers are being held accountable for student learning in the same way as their classroom peers. Improving the effectiveness of teachers is seen as the primary mechanism for improving student learning. In discussing how teaching effectiveness has evolved, I describe a relationship among the process-product paradigm, the ecological paradigm, and a neo-ecological paradigm called the instructional core. The latter paradigm extends our understanding of teaching effectiveness in new ways by describing the dynamic and interdependent relationship among teacher, student, and content in the gymnasium. It has significant implications for the professional development of teachers and the conduct of teaching effectiveness research. I conclude by discussing why content is so critical to conceptions of teaching effectiveness.

Health-related physical fitness children with severe and moderate developmental coordination disorder

The present study aims to examine physical fitness among children with developmental coordination disorder (DCD) with varying degrees of severity (moderate and severe - mDCD, sDCD), and a group of children without DCD (wDCD), in the city of Manaus, Brazil. Initially, 180 children aged 6-10 years old participated in this study. After being diagnosed according to the DSM-IV-TR, 63 children were then divided into three groups (21 in each group). Health-related physical fitness was measured by means of the Fitnessgram, which included several core components, namely, body composition, muscle strength and endurance, flexibility, and cardiorespiratory resistance. The results showed no statistically significant differences between both groups in any of the assessed components. However, when analyzing the results of each component according to the criteria of the Fitnessgram, we observed that, regardless of the classification group, less than half of the children achieved scores that, according to the motor tests, would classify them as having a healthy fitness. Children with sDCD, mDCD and wDCD presented similar levels of health-related physical fitness, with an unsatisfactory performance for the component strength and muscular endurance. We therefore emphasize the importance of further research in this area, more particularly when it comes to following the development of motor skills and physical fitness in children with DCD, as well as the observation of the interactions between these variables over time.

Is developmental coordination disorder a fundamental cause of inactivity and poor health-related fitness in children?

Developmental coordination disorder (DCD) is a common, neurodevelopmental disorder of children that results in significant impairment in everyday activities of living. Over the past two decades, a large body of work has documented associations between DCD, physical inactivity, and poor health-related fitness. The exact nature of these relations, however, has been relatively little studied. In this paper, we ask whether the balance of evidence supports the proposition that DCD is a fundamental cause of inactivity and poor fitness. To address this question, we apply Hill's criteria for causation. We conclude that the evidence is consistent with, and reasonably supportive of, this proposition, but does not exclude alternative explanations.

Seasonal variations in physical fitness among elementary school children

There is empirical evidence that children's physical activity is dependent on climatic conditions. In addition, a correlation between physical activity level and physical fitness has been identified. In this longitudinal study, we investigate whether seasons have an influence on physical fitness. A total of 145 German elementary school children were tested every six months over a two-year period. We used the German Motor Test 6-18 to assess physical fitness. Performance in the 6-min endurance run (P < 0.001), bidirectional jumping (P < 0.001), the standing long jump (P = 0.026), the 20 m sprint (P = 0.006) and the stand-and-reach task (P = 0.017) was significantly better in summer than in winter. There were no differences in the ability to balance backwards (P = 0.120); in the winter, the results for push-ups (P < 0.001) and sit-ups (P < 0.001) were better than those in the summer. We have shown that physical fitness is significantly influenced by the season. Consequently, when children's fitness tests are used (e.g. as the basis for intervention programs, for classifying health-risk groups or for recognising talent), the season in which testing occurred should be reported and accounted for in future studies.

Associations among selected motor skills and health-related fitness: indirect evidence for Seefeldt's proficiency barrier in young adults?

PURPOSE

This exploratory study examined the notion of Seefeldt's (1980) hypothesized motor skill "proficiency barrier" related to composite levels of health-related physical fitness (HRF) in young adults.

METHOD

A motor skill competence (MSC) index composed of maximum throwing and kicking speed and jumping distance in 187 young adults aged 18 to 25 years old was evaluated against a composite index of 5 health-related fitness (HRF) test scores. MSC (high, moderate, and low) and HRF indexes (good, fair, and poor) were categorized according to normative fitness percentile ranges. 2 separate 3-way chi-square analyses were conducted to determine the probabilities of skill predicting fitness and fitness predicting skill.

RESULTS

Most correlations among HRF and MSC variables by gender demonstrated low-to-moderate positive correlations in both men (12/15; r = .23-.58) and women (14/15; r = .21-.53). Chi-square analyses for the total sample, using composite indexes, demonstrated statistically significant predictive models, chi2(1, N = 187) = 66.99, p < .001, Cramer's V = .42. Only 3.1% of low-skilled (2 of 65) individuals were classified as having a "good" HRF. Only 1 participant (out of 65) who demonstrated high MSC was classified as having "poor" HRF (1.5%).

CONCLUSION

Although individual correlations among individual MSC and HRF measures were low to moderate, these data provide indirect evidence for the possibility of a motor skill "proficiency barrier" as indicated by low composite HRF levels. This study may generate future research to address the proficiency barrier hypothesis in youth as well as adults.

Prospective associations between sugar-sweetened beverage intakes and cardiometabolic risk factors in adolescents

BACKGROUND

High sugar-sweetened beverage (SSB) consumption is associated with cardiometabolic disturbances in adults, but this relation is relatively unexplored in children and adolescents.

OBJECTIVE

We tested the hypothesis that higher SSB intakes are associated with increases in cardiometabolic risk factors between 14 and 17 y of age.

DESIGN

Data were provided by 1433 adolescent offspring from the Western Australian Pregnancy Cohort (Raine) Study. At 14 and 17 y of age, SSB intakes were estimated by using a food-frequency questionnaire; body mass index (BMI), waist circumference, blood pressure, fasting serum lipids, glucose, and insulin were measured, and overall cardiometabolic risk was estimated. Prospective associations between cardiovascular disease risk factors and SSB intake were examined with adjustment for age, pubertal stage, physical fitness, socioeconomic status, and major dietary patterns.

RESULTS

The average SSB intake in consumers (89%) was 335 g/d or 1.3 servings/d. Girls who moved into the top tertile of SSB consumption (>1.3 servings/d) between 14 and 17 y of age had increases in BMI (3.8%; 95% CI: 1.8%, 5.7%), increased overweight and obesity risk (OR: 4.8, 95% CI: 2.1, 11.4), and greater overall cardiometabolic risk (OR: 3.2; 95% CI: 1.6, 6.2) (all P-trend ≤ 0.001). Girls and boys who moved into the top tertile of SSB intake showed increases in triglycerides (7.0-8.4%; P-trend ≤ 0.03), and boys showed reductions in HDL cholesterol (-3.1%; 95% CI: -6.2%, 0.1%; P-trend < 0.04) independent of BMI. Some associations were attenuated after adjustment for major dietary patterns.

CONCLUSION

Increased SSB intake may be an important predictor of cardiometabolic risk in young people, independent of weight status.

Exercise deficit disorder in youth: a paradigm shift toward disease prevention and comprehensive care

Despite the widely recognized benefits of daily play, recreation, sports, and physical education on the physical and psychosocial well-being of children and adolescents, many contemporary children and adolescents worldwide do not meet the recommendations for daily physical activity (PA). The decline in PA seems to start early in life, which leads to conditions characterized by reduced levels of PA in the pediatric population that are inconsistent with current public health recommendations. Unlike many other diseases and disorders in pediatrics, physical inactivity in youth is unique in that it currently lacks a clinical gold standard for diagnosis. This makes the diagnosis and treatment medically challenging, though no less important, as the resultant ramifications of a missed diagnosis are of significant detriment. Exercise-deficient children need to be identified early in life and treated with developmentally appropriate exercise programs designed to target movement deficiencies and physical weaknesses in a supportive environment. Without such interventions early in life, children are more likely to become resistant to our interventions later in life and consequently experience adverse health consequences. Integrative approaches that link health care professionals, pediatric exercise specialists, school administrators, community leaders, and policy makers may provide the best opportunity to promote daily PA, reinforce desirable behaviors, and educate parents about the exercise-health link.

The psychometric properties of the McCarron Assessment of Neuromuscular Development as a longitudinal measure with Australian youth

The importance of considering age and sex differences in the assessment of motor performance has been largely overlooked. This study examines the psychometric properties of the US developed McCarron Assessment of Neuromuscular Development (MAND) using data from a longitudinal sample of 986 Australian youth at 10, 14 and 17 years. A key finding was the sex and age interaction of the Neuromuscular Developmental Index (NDI) (F=121.46, p<.001). Males had a significantly lower mean NDI score at 10 years and the females had a lower score at 17 years. The factor structure differed from the US samples (McCarron, 1997) at each age and between males and females. The sex specific analyses showed that the underlying structure was more complex for younger females. Although the MAND remains a useful test of motor performance for Australian children, further consideration is warranted regarding sex differences, the relevance of the US based normative tables and factor structures.

Gender difference in the relationship between passive smoking exposure and HDL-cholesterol levels in late adolescence

BACKGROUND

High-density lipoprotein-cholesterol (HDL-C) levels are influenced by gender and by genetic and environmental factors. We aimed to assess the impact of passive smoking exposure since birth on HDL-C levels of nonsmoking adolescents at age 17 years and to determine whether there was a gender difference in the relationship between smoking exposure and HDL-C.

METHODS

A total of 804 nonsmoking adolescents with biochemical, anthropometric, and lifestyle data from a cohort of 1754 adolescents (mean age, 17 ± 0.25 y) of the Western Australian Pregnancy Cohort (Raine) Study had data of maternal smoking during pregnancy and smoking exposure in the household over 17 years. HDL-C was analyzed using multivariable linear regression, with adjustment for early-life, adiposity, and current lifestyle confounders.

RESULTS

HDL-C levels were significantly lower in girls exposed to passive smoking compared to those not exposed (regression coefficient b = -0.09 [95% confidence interval, -0.15, -0.03]); this was not observed in boys (b = 0.02 [95% confidence interval, -0.04, 0.08]), with a significant sex interaction P = .009. The effects of passive smoking in girls persisted after adjusting for oral contraceptive use.

CONCLUSIONS

This study has shown a gender difference in the relationship between passive smoking exposure since birth and HDL-C in late adolescence. Exposure to passive smoking in girls could have adverse consequences on their risk of cardiovascular disease in adulthood. These findings reinforce the need for future public health measures to reduce children's exposure to passive smoking.

Exercise-deficit disorder in children: are we ready to make this diagnosis?

Primary care physicians, particularly pediatricians, are expected to promote physical activity and prescribe exercise to patients. Unfortunately, many health care professionals do not have adequate skills or experience in this area, making exercise intervention logistically and psychologically challenging. Exercise-deficit disorder (EDD), which is a new term to the literature, is defined as reduced levels of moderate-to-vigorous physical activity, inconsistent with public health recommendations. Physicians are in a unique position to identify children who are deficient in exercise and initiate prevention strategies. To aid physicians in the diagnosis and treatment of children with EDD, we propose integrating exercise assessment into primary care practice, and, when appropriate, referral to a pediatric exercise specialist. This approach should ensure adequate development of muscle strength and motor skills that are required for successful physical activity participation. The timely identification of children with EDD is essential in preventing resistance to intervention. Connecting pediatric health care professionals with pediatric exercise specialists, culminating in an established professional collaborative system, is critical for promoting healthy behaviors throughout childhood and adolescence.