The Coordination and Activity Tracking in CHildren (CATCH) study: rationale and design

Comorbid Developmental Coordination Disorder and ADHD: The Effects on Emotional and Behavioural Problems in Young Children

Both DCD and ADHD are recognised neurodevelopmental conditions, however, their co-occurrence and subsequent effects remain insufficiently explored. This paper aims to address this gap by examining the relationship between motor proficiency and ADHD symptoms in young children, and elucidating the combined impact on internalising and externalising symptoms. Data from the Coordination and Activity Tracking in CHildren (CATCH) study (n = 532) were analysed. Children aged 6-9years were classified into typically motor developing (TMD; Movement Assessment Battery for Children-2nd Edition [MABC-2] > 16th percentile), at risk for DCD (DCDr; MABC-2 6th ≤ 16th percentile), or with probable DCD (pDCD; MABC-2 < 6th percentile). ADHD symptoms were assessed using the Conners Parent Rating Scale, 3rd Edition, and mental health symptoms assessed with the Child Behaviour Checklist for school-aged children (CBCL). 28% of children with pDCD and 19% of children with DCDr had clinically significant ADHD symptoms. Those with comorbid pDCD and clinically significant ADHD symptoms exhibited significantly elevated CBCL scores compared to those without clinically significant ADHD symptoms. The increased experience of mental health challenges in children with comorbid pDCD and clinically significant ADHD symptoms underscores the importance of universal screening for ADHD and mental health concerns in children with DCD.

Developmental Coordination Disorder and Early Childhood Trajectories of Physical Activity

PURPOSE

Developmental coordination disorder (DCD) is a common neurodevelopmental disorder characterized by motor impairments and subsequent physical activity (PA) deficits in middle childhood. It is not well understood when this gap in PA emerges. The purpose of the current study was to examine the longitudinal trajectories of device-assessed PA in a large cohort of children with and without DCD from ages 4 to 8 yr.

METHODS

Children ( n = 535; age, 4-5 yr) completed four annual assessments as part of a prospective cohort study. Children were classified into three groups based on their average performance on the Movement Assessment Battery for Children-Second Edition: probable DCD <6th percentile ( n = 72), at risk for DCD between the 6th and 16th percentile ( n = 127), and typically developing >16th percentile ( n = 336). Moderate-to-vigorous PA (MVPA) and average PA volume (vector counts per minute) were assessed using ActiGraph accelerometers. A series of linear mixed-effects models were used to examine longitudinal PA trajectories between groups.

RESULTS

Children in both the probable DCD and at-risk for DCD groups engaged in significantly less MVPA compared with the typically developing group, whereas the deficit in PA volume was only marginally evident in the probable DCD group. The rate of change did not differ by group, indicating that this deficit is relatively consistent across the early childhood period.

CONCLUSIONS

Young children with DCD are in an MVPA deficit that persists across early childhood. Early interventions targeting motor skills and PA may help to reduce this gap and promote positive trajectories of health among children with motor difficulties.

Paediatric motor difficulties and internalising problems: an integrative review on the environmental stress hypothesis

The current study aims to provide an in-depth analysis and extension of the Environmental Stress Hypothesis (ESH) framework, focusing on the complex interplay between poor motor skills and internalising problems like anxiety and depression. Using an integrative research review methodology, this study synthesises findings from 38 articles, both empirical and theoretical, building upon previous foundational works. The hypothesis posits that poor motor skills serve as a primary stressor, leading to internalising problems through various secondary stressors. A rigorous comparison of data was conducted, considering study design, findings, and methodologies-while exploring variables such as age, sex, and comorbidities. The study also enhances the ESH framework by including intrapersonal stressors and introducing resource buffers, including optimism and familial support as additional influencing factors. This multi-level approach yields a more nuanced and comprehensive ESH framework, highlighting the need for future studies to consider variables that intersect across multiple domains and how the relationship between poor motor skills and internalising problems may vary across different life stages.

Auditory rhythm facilitates perception and action in children at risk for developmental coordination disorder

Developmental Coordination Disorder (DCD) is a common neurodevelopmental disorder featuring deficits in motor coordination and motor timing among children. Deficits in rhythmic tracking, including perceptually tracking and synchronizing action with auditory rhythms, have been studied in a wide range of motor disorders, providing a foundation for developing rehabilitation programs incorporating auditory rhythms. We tested whether DCD also features these auditory-motor deficits among 7-10 year-old children. In a speech recognition task with no overt motor component, modulating the speech rhythm interfered more with the performance of children at risk for DCD than typically developing (TD) children. A set of auditory-motor tapping tasks further showed that, although children at risk for DCD performed worse than TD children in general, the presence of an auditory rhythmic cue (isochronous metronome or music) facilitated the temporal consistency of tapping. Finally, accuracy in the recognition of rhythmically modulated speech and tapping consistency correlated with performance on the standardized motor assessment. Together, the results show auditory rhythmic regularity benefits auditory perception and auditory-motor coordination in children at risk for DCD. This provides a foundation for future clinical studies to develop evidence-based interventions involving auditory-motor rhythmic coordination for children with DCD.

Cumulative Prenatal Risk Factors and Developmental Coordination Disorder in Young Children

OBJECTIVES

To examine the effect of cumulative prenatal risk factors (RFs) on the presence of Developmental Coordination Disorder (DCD) in young children.

METHODS

Participants (N = 589, 338 boys, Mage = 4.5 ± 0.5 years) were from a larger cohort study, the Coordination and Activity Tracking in Children (CATCH). Motor coordination was assessed using the Movement Assessment Battery for Children- 2nd Edition. Children were classified as at risk for DCD (DCDr) based on European Academy of Childhood Disability guidelines. RFs were obtained through a parent-completed survey. A multiple logistic regression was conducted to examine the effect of the RFs on DCD.

RESULTS

Results showed that the odds of a child having DCDr are significantly higher with a greater total number of prenatal RFs, after adjustment for mother's age at child's birth, child's sex, child's age, marital status and total annual household income (OR = 1.48, p < 0.01).

CONCLUSIONS

These findings warrant further investigation into the cumulative impact of multiple prenatal RFs and whether specific combinations of RFs might be more strongly linked to DCD than others. These results provide additional insight into possible causes and prevention of DCD.

Reliability of field- and laboratory-based assessments of health-related fitness in preschool-aged children

OBJECTIVES

Reliable measurements of health-related fitness-cardiorespiratory endurance, muscular endurance, muscular strength, body composition, and flexibility-are imperative for understanding and tracking health-related fitness from the preschool age. This study aimed to examine the test-retest reliability of field-based (i.e., sit and reach [standard and back-saver], standing long jump, grip strength); and laboratory-based (i.e., Bruce Protocol Treadmill Test, Wingate Anaerobic Test) assessments of health-related fitness in preschool aged children (4-5 years).

METHODS

Forty-two typically developing children participated in both assessment time points separated by 2-3 weeks. All fitness assessments were administered individually and repeated in the same order by the same assessor. Heteroscedasticity was examined for each parameter. Intraclass correlation coefficients were calculated to assess test-retest reliability.

RESULTS

All parameters were homoscedastic. Test-retest reliability for the field-based tests and Bruce Protocol Treadmill Test parameters were moderate to good. Test-retest reliability for the Wingate Test parameters were good to excellent for maximum pedal rate, peak power, and peak power/kg; mean power and fatigue measured at 10 and 30 s demonstrated moderate to excellent test-retest reliability.

CONCLUSION

The standard sit and reach, grip strength, and short-term muscle power from the Wingate test are reliable assessments of health-related fitness in preschool-aged children.

Stability of M-ABC-2-measured motor functioning in early childhood: Evidence from a large prospective cohort

AIM

Some studies have reported that children with poor motor functioning tend to improve over time. However, much existing research does not account for regression towards the mean (RTM). Here, we examine measurement stability among 589 children aged 4-5 years.

METHOD

We administered the Movement Assessment Battery for Children 2nd Edition annually to 269 children initially scoring above and 252 at or below the 16th percentile. We measured agreement between year 1 and year 2 standard scores using Pearson correlation and derived expected regression towards the mean (RTM). We then regressed follow-up on baseline scores, controlling for relative age, sex, and exact interval between assessments. Finally, we performed a small illustrative simulation.

OUTCOMES AND RESULTS

The mean score in the poor-coordination group rose from 5.6 (SD = 1.5) to 7.2 (SD = 2.8). Year 1 and year 2 scores were correlated at r = 0.66, corresponding to predicted RTM in the MI group of 1.56, close to the observed change of 1.57. Degree of change was not associated with time between assessments.

INTERPRETATION

Observed improvements in motor functioning were consistent with measurement error. The stability of motor functioning may be greater than it appears from past research, and reported functional improvements in some studies may be illusory. WHAT THIS PAPER ADDS?

Effects of Comorbid Developmental Coordination Disorder and Symptoms of Attention Deficit Hyperactivity Disorder on Physical Activity in Children Aged 4-5 Years

Developmental coordination disorder (DCD) is often comorbid with attention-deficit/hyperactivity disorder (ADHD). While children with DCD engage in less moderate-to-vigorous physical activity (MVPA) compared to typically developing (TD) children, research pertaining to how ADHD affects this relationship is limited. We investigated the effect of ADHD on MVPA among children at risk for DCD (DCDr). 507 children aged 4-5 years (DCDr = 233, TD = 274) participated. Motor skills were assessed using the Movement Assessment Battery for Children-2nd edition (DCDr; ≤ 16th percentile), ADHD symptoms were assessed using the Child Behaviour Checklist, and Actigraph accelerometers measured MVPA over seven days. DCD did not negatively affect MVPA, however, after adjusting for ADHD symptoms, the effect of DCD became significant and was driven by symptoms of inattention. Symptoms of ADHD may be suppressing the negative effects of DCD on MVPA, highlighting the importance of assessing and controlling for ADHD symptoms in this population.

Investigating the mediating role of internalizing and externalizing problems on physical fitness in children at risk for Developmental Coordination Disorder

Children with Developmental Coordination Disorder (DCD) have poorer fitness and greater internalizing/externalizing problems compared with typically developing (TD) children. The purpose of this study was to examine the potential mediating role of internalizing/externalizing problems on the relationship between children at risk for DCD (DCDr) and physical fitness. Participants (N = 589) included 288 children with DCDr (M_age = 4.9, 67% male) and 301 TD children (M_age = 5.0, 48% male). Motor skills were assessed using the Movement Assessment Battery for Children-2^nd edition (DCDr: at or below the 16th percentile, TD: >16th percentile). Parent-reported internalizing/externalizing problems were measured using the Child Behaviour Checklist. Physical fitness was measured using the Bruce protocol maximal treadmill test and a 30-second Wingate test. Tests for indirect (mediation) effects were assessed using the PROCESS v3.5 software macro. Children with DCDr had higher internalizing and externalizing problems (p < 0.001, d = 0.35-0.46) and poorer fitness levels (p < 0.001, ηp² = 0.05-0.09). Internalizing problems mediated fitness performance on both the treadmill and Wingate test; however, externalizing problems showed no mediating effects. Thus, interventions targeting internalizing problems may contribute to improving performance on fitness-based tasks among children with DCDr. Novelty: Children at risk for DCD have poorer fitness when compared with TD children. Children at risk for DCD experience greater internalizing/externalizing problems. Internalizing problems were found to mediate the DCD-physical fitness relationship.

Associations Between Fitness, Physical Activity, and Fatness in Preschool Children With Typical and Atypical Motor Coordination

PURPOSE

Increased adiposity in children confers a higher risk of cardiovascular disease in later life, with low cardiorespiratory fitness strongly linked to poorer metabolic health. Children with motor coordination problems are likely to be less physically fit and at a higher risk of obesity. In this study, we examined the associations between aerobic and anaerobic fitness, device-measured physical activity, and body adiposity in children (aged 4-5 years) with typical and atypical motor coordination.

METHODS

Baseline data from the Coordination and Activity Tracking in CHildren (CATCH) cohort study were utilised. The assessments included aerobic and anaerobic fitness via time-to-exhaustion on Bruce treadmill test and normalised mean power on Wingate cycling test, respectively; light physical activity (LPA), moderate-to-vigorous physical activity (MVPA), and sedentary time via accelerometry; and body adiposity (%) via bioelectrical impedance analysis (BIA). The Movement Assessment Battery for Children-Second Edition (MABC-2) was used to assess motor coordination and classify children as typically developing (TD, >16th percentile) or at risk of developmental coordination disorder (DCD, ≤16th percentile). General linear regression models were fitted to examine associations.

RESULTS

The analyses included 495 participants (5.0 ± 0.6 years, 56% male, and body adiposity 22.7 ± 4.2%). Aerobic fitness (β = -0.006, p < 0.001) and MVPA (β = -0.018, p = 0.045) were negatively associated with body adiposity when adjusted for age, sex, and MABC-2 score. There was no relationship between sedentary time and body adiposity. There were no interactions of sex or MABC-2 score with any variable.

CONCLUSION

Lower aerobic fitness and MVPA were associated with higher body adiposity in preschoolers, regardless of motor coordination. Interventions targetting improved aerobic fitness and MVPA are therefore warranted in both TD and atypically developing preschoolers. Whether maintaining high aerobic fitness in children with possible DCD confers protection against obesity requires longitudinal investigation.

Ecological validity of the PERF-FIT: correlates of active play, motor performance and motor skill-related physical fitness

Background

Active games are important health enhancing physical activities in children with and without developmental disorders and will help children to develop fundamental motor skills, while inactivity exacerbates coordination difficulties and increases the risk of obesity. Regular engagement in active play promotes physical, social and cognitive development. It is therefore important to know if children have the capabilities for healthy behavior. Motor skills and muscular fitness are both important components to participate in play, sport and leisure. The Performance and Fitness (PERF-FIT) test battery integrates motor skills (running, jumping, hopping, catching, bouncing, throwing, balance) and muscular fitness (explosive power and muscular endurance) needed in many forms of active play.

Aim

To test the ecological validity of the PERF-FIT test battery; a field-based test integrating motor skill proficiency and muscular fitness.

Methods

Seventy-five children were assessed on the PERF-FIT, Movement Assessment Battery for Children (MABC)-2 and performance in 6 active games was scored. Of these children, 52 children scored in the normal range and 23 (or 30.3%) below the 16^th percentile of the MABC-2. Association between the outcomes of the two tests and the 6 games was calculated.

Results

High to moderate associations were found between game scores and PERF-FIT items; moderate to low associations between game scores and MABC-2 items. Principle axes factor analysis with oblique rotation revealed communalities between the explosive power and agility items of the PERF-FIT and the running and ball catching games but not between the games and the balance items.

Conclusions and implications

Scores on the PERF-FIT are significantly related to performance in active play. The tool is able to measure aspects of motor skills, muscle endurance and explosive power needed in children's active games and could be used as an additional tool to measure requirements for participation in everyday physical activity in children with and without developmental disorders.

Inferior Auditory Time Perception in Children With Motor Difficulties

Accurate time perception is crucial for hearing (speech, music) and action (walking, catching). Motor brain regions are recruited during auditory time perception. Therefore, the hypothesis was tested that children (age 6-7) at risk for developmental coordination disorder (rDCD), a neurodevelopmental disorder involving motor difficulties, would show nonmotor auditory time perception deficits. Psychophysical tasks confirmed that children with rDCD have poorer duration and rhythm perception than typically developing children (N = 47, d = 0.95-1.01). Electroencephalography showed delayed mismatch negativity or P3a event-related potential latency in response to duration or rhythm deviants, reflecting inefficient brain processing (N = 54, d = 0.71-0.95). These findings are among the first to characterize perceptual timing deficits in DCD, suggesting important theoretical and clinical implications.

Cross-Sectional Associations Between Wake-Time Movement Compositions and Mental Health in Preschool Children With and Without Motor Coordination Problems

Movement behaviors have been found to be important correlates of health for children and may be particularly important for children with Developmental Coordination Disorder (DCD) who often experience greater mental health problems. To date, however, little research has investigated the daily movement composition of preschool children with Developmental Coordination Disorder (DCD) and/or its association with mental health. The purpose of the current study was to: (1) examine whether differences in movement compositions (i.e., sedentary time, light physical activity, moderate-to-vigorous physical activity) exist between typically developing (TD) preschool-age children and those at risk for DCD (rDCD); and (2) investigate associations between movement compositions and mental health indicators. This cross-sectional study used the baseline cohort data from the Coordination and Activity Tracking in CHildren (CATCH) study. A total of 589 preschool-age children (Mage = 4.94 ± 0.59 years; 57.4% boys) were included in this analysis, of which 288 scored at or below the 16th percentile on the Movement Assessment Battery for Children-2 and were thus classified as rDCD. Wake time movement behaviors were measured using accelerometers and parents completed the Child Behavior Checklist to assess their child's mental health (i.e., internalizing and externalizing problems). Compositional data analysis techniques were used. After adjusting for potential confounders, the results demonstrated similar movement compositions between TD and rDCD children. Among the full sample, findings revealed a significant association between sedentary time and externalizing problems, however, each of the other associations did not reach statistical significance. These results are consistent with emerging evidence demonstrating similar patterns of physical activity and sedentary time among TD children and those classified as rDCD during the preschool years. Although movement behaviors explained little variance in mental health during this period, future research should investigate when movement compositions diverge, and how these changes may impact the mental health of TD children and those classified as rDCD later in childhood.

Does physical activity and BMI mediate the association between DCD and internalizing problems in early childhood? A partial test of the Environmental Stress Hypothesis

BACKGROUND AND PURPOSE

Young children with Developmental Coordination Disorder (DCD) are more likely to experience internalizing problems, such as depression and anxiety, than typically developing (TD) children. Currently, the underlying mechanisms resulting in increased internalizing problems in DCD remains unknown; however, a previous study based on the Environmental Stress Hypothesis (ESH) indicated that physical inactivity and obesity may mediate the relationship between DCD and internalizing problems. The purpose of this study is to investigate the relationships among DCD, internalizing problems, physical activity, and BMI, and the role of sex in these relationships in preschool children, a population for which we currently have very limited data.

METHODS

Young children between the ages of 4 and 5 years enrolled in the Coordination and Activity Tracking in CHildren (CATCH) study comprised the sample (n = 589). Of these, 288 (193 boys, 67.0%) were classified as at risk for DCD (rDCD), based on scoring at or below 16th percentile on the Movement Assessment Battery for Children - Second Edition. Physical activity was measured using accelerometers and height and weight were measured by trained research assistants, while parents completed the Child Behavior Checklist to rate internalizing problems. The mediating effects of physical activity and BMI were tested on the relationship between rDCD and internalizing problems.

RESULTS

Children with rDCD reported more internalizing problems than TD children. While there was a direct effect of rDCD on internalizing problems, neither physical activity nor BMI were found to mediate this relationship.

CONCLUSION

The findings from this study support co-occurring internalizing problems in preschool children with DCD, and extend these findings to demonstrate that this relationship is not explained by physical activity or BMI in early childhood. Further research should be directed toward other psychosocial factors identified in the ESH to better understand the underlying mechanisms between DCD and co-occurring internalizing problems.

Perceptions of Ability Mediate the Effect of Motor Coordination on Aerobic and Musculoskeletal Exercise Performance in Young Children at Risk for Developmental Coordination Disorder

This study examined the effects of perceptions of motor abilities on aerobic and musculoskeletal exercise performance in young children at risk for developmental coordination disorder (rDCD). The participants (N = 539) were part of a larger cohort study, the Coordination and Activity Tracking in Children (CATCH) study. The Movement Assessment Battery for Children (2nd Edition) was used to determine rDCD children. Perceptions of motor abilities were measured by the Perceived Efficacy and Goals Setting system. Aerobic exercise performance was measured using the Bruce Protocol treadmill test, and musculoskeletal exercise performance was assessed using the standing long jump and the Wingate Anaerobic test. The rDCD children reported lower Perceived Efficacy and Goals Setting scores and performed worse on all exercise performance measures. Perceptions of ability also mediated the relationship between developmental coordination disorder and each exercise performance test. It is concerning that children with low motor coordination report lower perceptions of ability even at a very young age.

Field-Based Tests of Strength and Anaerobic Capacity Used in Children With Developmental Coordination Disorder: A Systematic Review

OBJECTIVE

Children with developmental coordination disorder (DCD) are reported to have lower levels of strength and anaerobic capacity. The purpose of this study was to (1) identify field-based tests for strength and anaerobic capacity used in studies comparing children with DCD and children who were typically developing (TD), (2) examine the methodological quality of studies reporting psychometric properties and rate the psychometric properties of the examined test, and (3) summarize available evidence by combining the methodological quality of the studies and the quality of the psychometric properties of the test.

METHODS

An electronic search was conducted in July 2019 in 4 electronic databases. For purpose 1, primary studies were included with no exclusion of study design in which children aged 4 to 18 years with DCD were compared with children who were TD on strength and/or anaerobic capacity measures. For purpose 2, primary studies were included with no exclusion of study design in which a psychometric property was investigated. The Consensus-Based Standards for Selection of Health Measurement Instruments (COSMIN) was used to evaluate the methodological quality of the 34 studies and rate the psychometric properties of the tests used.

RESULTS

Hand-held dynamometer, bent knee push-up, vertical jump, standing long-jump, functional strength measurement, fitness test, and test battery can be recommended for TD, and the shuttle run item of the Bruininks-Oseretsky Test of Motor Proficiency-Second Edition and 10 m × 5 m sprints (straight and slalom) can be recommended for DCD.

CONCLUSION

Information regarding psychometric properties of field-based tests for strength and anaerobic capacity in children with DCD is lacking.

IMPACT

Information about the psychometric properties of field-based tests for strength and anaerobic capacity in children with DCD is lacking. More information is available on TD children, but it is also not complete; information regarding validity and responsiveness, especially, is missing. When using measures in children with DCD, it is important to keep in mind this lack of evidence for the validity and reliability of the outcomes for this target group.

Assessing the Validity of Standing Long Jump to Predict Muscle Power in Children With and Without Motor Delays

PURPOSE

To determine the validity of standing long jump (SLJ) for predicting muscle power in children with and without developmental coordination disorder (DCD).

METHODS

A total of 589 children were recruited as part of the Coordination and Activity Tracking in CHildren study (251 girls and 338 boys; mean age 59.2 mo). Children were classified as typically developing (>16th percentile), at risk for DCD (sixth to 16th percentile), or probable DCD (<sixth percentile) based on Movement Assessment Battery for Children-Second Edition scores. SLJ was measured from the back of the heel. Peak power and mean power over 10 seconds and 30 seconds were measured using the Wingate test.

RESULTS

SLJ was moderately correlated with peak and mean powers in all groups (R = .51-.55). Regression analysis showed that when combined with weight and age, SLJ performance could predict peak power and mean power over 10 seconds and 30 seconds in typically developing children (adjusted R2 = .68, .61, and .58, P < .001, respectively) and in children with risk for DCD (adjusted R2 = .74, .65, and .60, respectively) and probable DCD (adjusted R2 = .68, .61, and .59, respectively).

CONCLUSIONS

SLJ, in combination with weight and age, may be used to measure muscle power in typically developing children, and in children with risk for DCD and probable DCD. This measure can be used as an inexpensive estimate of musculoskeletal fitness in children regardless of motor abilities.

Physical activity in young children at risk for developmental coordination disorder

AIM

To examine cross-sectional differences in patterns of daily physical activity accumulation between preschool children at risk for developmental coordination disorder (DCD) compared to typically developing children.

METHOD

In total, 514 children (292 males, 222 females; 4-5y) were recruited as part of the Coordination and Activity Tracking in CHildren (CATCH) study. Motor competence was assessed using the Movement Assessment Battery for Children, Second Edition; children scoring ≤5th centile comprised the probable DCD group (pDCD, n=87), between the 6th and 16th centile were considered to be at risk for DCD (rDCD, n=149), and >16th centile were considered typically developing (n=278). Seven-day physical activity was measured using hip-worn accelerometers. Average daily intensity of activity, frequency, and duration of moderate-to-vigorous physical activity (MVPA) bouts, and triaxial activity counts per minute were determined.

RESULTS

No differences in daily activity in any intensity or axis of movement were found among the three groups. However, young children with pDCD accumulated their MVPA in slightly shorter bouts compared to typically developing children.

INTERPRETATION

Young children at risk for DCD are not yet in an activity deficit. This may be because of the low motor skill demands of play in this age group. Early motor interventions may be able to promote continued physical activity participation in children with DCD.

WHAT THIS PAPER ADDS

Preschool children at risk for developmental coordination disorder (DCD) are not less active than their peers. Overall intensity and frequency of daily activity bouts are similar among motor groups. Children with probable DCD accumulate their activity in shorter bouts.

Cohort profile: the Canadian coordination and activity tracking in children (CATCH) longitudinal cohort

PURPOSE

Developmental coordination disorder (DCD) is a prevalent, neurodevelopmental disorder affecting 2% to 5% of children, which is characterised by fine and gross motor problems. Children with DCD have been shown to be less fit and physically active than other children; however, the direction of causality is unknown as previous studies have typically been done in older children when the differences in fitness and physical activity are already present. The aim of the Coordination and Activity Tracking in Children (CATCH) study is to specifically address the issue of precedence by recruiting a large sample of children in early childhood.

PARTICIPANTS

CATCH comprises a community-based sample of parents and children 4 to 5 years of age divided into two groups: at risk for DCD (rDCD; n=287) and typically developing (TD; n=301). Inclusion in the rDCD group required a score at or below the 16^th percentile on a standardised test of motor coordination and a score above 70 on a standardised test of intelligence.

FINDINGS TO DATE

Children in the rDCD group contained a higher proportion of males (67% vs 48%, χ²=21.9, p<0.001). Children in the rDCD group had lower mean IQs, aerobic and musculoskeletal fitness than children in the TD group (p<0.001 for all). There were no differences observed between groups for body composition or physical activity. Parent characteristics did not differ, with one exception: partners of reporting parents of rDCD children were less likely to hold a university degree (44% vs 57%, χ²=7.4, p=0.004). According to parent report, rDCD children experienced more problems in self-care, school and leisure activities (p<0.001 for all).

FUTURE PLANS

Children are being followed up annually for 3 years. At each follow-up, motor coordination testing is repeated, and data are collected on physical activity, fitness and social-emotional problems.

Influence of the Box Dimensions on the Reliability and Validity of the Sit and Reach in Preschoolers

Ayán Pérez, C, Martínez de Quel, Ó, Álvarez Pérez, S, and González Baamonde, S. Influence of the box dimensions on the reliability and validity of the sit and reach in preschoolers. J Strength Cond Res 34(9): 2683-2692, 2020-This study aimed at analyzing the reliability and validity of the sit and reach (SR) test, when it was performed with a standard SR (SSR) or an adapted SR (ASR) box in preschoolers. To accomplish this, both tests were administered 3 times (familiarization, test, and retest) to a group of 148 children (mean age, 4.99 ± 0.94 years; 49.3% girls), with a week interval between each assessment. The obtained results in each test were compared with those obtained in the passive straight leg raise (PSLR) test with the aim of identifying their construct validity. The internal consistency was found to be between good and excellent for the SSR (α: 0.83-0.92) and excellent for the ASR (α: 0.92-0.96). The SSR showed a good and a fair reliability (intraclass correlation coefficient [ICC], 0.71-0.86), whereas the ASR showed an excellent reliability (ICC, 0.90-0.94) except for the 3-year-old children group (ICC, 0.84). Absolute reliability was excellent for the ASR, whereas the SSR yielded higher SEM and minimum detectable change percentage values. Regarding the criterion-related validity, statistically significant fair correlations were observed between both SR tests and the PSLR test. The ASR yielded higher levels of statistical significance as well as greater correlation coefficients than the SSR. This finding indicates that when it comes to assess flexibility through a low cost and easy-to-implement lineal test in preschoolers, it is advisable to use the SR with a box of reduced dimensions.

A mixed-longitudinal study of children's growth, motor development and cognition. Design, methods and baseline results on sex-differences

BACKGROUND

There is a renewed interest in longitudinal studies which link children's growth, motor and cognition development. This is important for both educational outcomes and identification of children who are at risk.

AIM

To identify cross-sectional sex-differences.

SUBJECTS AND METHODS

In total, 1166 Portuguese children, aged 4-11 years, were recruited into the Growth, Motor Development and Cognition Study (GMDC-Vouzela study). Measures included: anthropometry, gestational development, motor coordination, cognitive performance, laterality, physical fitness, metabolic syndrome risk, lifestyle characteristics and environmental exposures. Analysis of covariance was used to compare outcomes between boys and girls, adjusting for chronological age.

RESULTS

Most variables did not show significant differences between the sexes (p > 0.05). However, girls had more body fat mass than boys (p < 0.05) and boys were significantly heavier at birth (p < 0.05); furthermore, boys outperformed girls in a hopping high coordination test (p < 0.001) and were more physically fit (p < 0.05).

CONCLUSIONS

Baseline results from the GMDC-Vouzela study indicate the dynamic relationships between children's biological and environmental characteristics. They also highlight lifestyle traits that will most likely effect subsequent growth, motor and cognitive development.

Effect of Physical Activity on Cognitive Development: Protocol for a 15-Year Longitudinal Follow-Up Study

The aim of the study is to investigate the relationship between physical activity as assessed by accelerometers and cognitive development across the human age ranges (from children and adolescents to adults). Additionally, this study seeks to explore whether physical activity contributes to cognitive development via modification of plasma insulin-like growth factor 1 (IGF-1) and brain-derived neurotrophic factor (BDNF). In the study, 500 preschool children (3.5–5.5 years old) are taking part in 6 triennial assessment waves over the span of 15 years. At each wave, participant measures included (a) 7-day physical activity monitoring using ActiGraph's GT3X accelerometers, (b) the evaluation of cognitive development, (c) anthropometric and physical fitness assessments, (d) plasma IGF-1 and BDNF concentrations, and (e) retrospective questionnaires. Linear regression models are used to examine the effect of physical activity on cognitive development; plasma IGF-1 and BDNF concentrations are considered as mediators into data analyses. The results of the study may help to inform future health interventions that utilize physical activity as a means to improve cognitive development in children, adolescents, and adults. Additionally, the study may assist in determining whether the putative effects occur via modification of plasma IGF-1 or BDNF concentrations.

Elaboration of the Environmental Stress Hypothesis-Results from a Population-Based 6-Year Follow-Up

The aim of this paper was to contribute to the elaboration of the Environmental Stress Hypothesis framework by testing eight hypotheses addressing the direct impact of gross motor coordination problems in elementary-school on selected physical, behavioral and psychosocial outcomes in adolescence. Results are based on a longitudinal sample of 940 participants who were (i) recruited as part of a population-based representative survey on health, physical fitness and physical activity in childhood and adolescence, (ii) assessed twice within 6 years, between the ages of 6 and 10 years old as well as between the ages of 12 and 16 years old (Response Rate: 55.9%) and (iii) classified as having gross motor coordination problems (N = 115) or having no gross motor coordination problems (N = 825) at baseline. Motor tests from the Körperkoordinationstest, measures of weight and height, a validated physical activity questionnaire as well as the Strength and Difficulties Questionnaire were conducted. Data were analyzed by use of binary logistic regressions. Results indicated that elementary-school children with gross motor coordination problems show a higher risk of persistent gross motor coordination problems (OR = 7.99, p < 0.001), avoiding organized physical activities (OR = 1.53, p < 0.05), an elevated body mass (OR = 1.78, p < 0.05), bonding with sedentary peers (OR = 1.84, p < 0.01) as well as emotional (OR = 1.73, p < 0.05) and conduct (OR = 1.79, p < 0.05) problems in adolescence in comparison to elementary-school children without gross motor coordination problems. However, elementary-school children with gross motor coordination problems did not show a significantly higher risk of peer problems (OR = 1.35, p = 0.164) or diminished prosocial behavior (OR = 1.90, p = 0.168) in adolescence, respectively in comparison to elementary-school children without gross motor coordination problems. This study is the first to provide population-based longitudinal data ranging from childhood to adolescence in the context of the Environmental Stress Hypothesis which can be considered a substantial methodological progress. In summary, gross motor coordination problems represent a serious issue for a healthy transition from childhood to adolescence which substantiates respective early movement interventions.