Original research
Tracking cardiorespiratory fitness and physical activity in children with and without motor coordination problems

https://doi.org/10.1016/j.jsams.2016.08.025Get rights and content

Abstract

Objectives

Previous research has shown children with Developmental Coordination Disorder (DCD) have lower cardiorespiratory fitness (CRF) than typically developing (TD) children. This has been hypothesized to be due to an activity deficit, whereby poor motor functioning discourages children from participating in physical activities, but this hypothesis has not been directly tested. In this study, we use longitudinal data to measure the extent to which physical activity explains differences in CRF between children with and without motor coordination deficits.

Design

Longitudinal observational study.

Methods

The study sample is an open cohort of children, numbering 2278 at baseline (age 9–10), that was followed for up to 5 years (to age 13–14). Motor skills were assessed once over the study period. Children scoring at or below the 5th percentile (n = 103) on the Bruininks–Oseretsky Test of Motor Proficiency-Short Form were considered to have possible DCD (pDCD). CRF (estimated peak VO2) was estimated from performance on the Léger 20 m shuttle run test, and physical activity was measured with the Participation Questionnaire. Both fitness and physical activity were measured up to 7 times over the study period.

Results

Children with pDCD had significantly lower CRF than their TD peers at each time point. CRF declined for both groups, but this decline was steeper for children with pDCD. Physical activity explained only a small part of the difference in CRF.

Conclusions

The activity deficit did not contribute to the persistent and gradually widening gap in CRF between children with and without possible DCD. Possible reasons for this and future directions are discussed.

Introduction

Developmental Coordination Disorder (DCD) is a chronic neurodevelopmental condition affecting between 2 and 6% of all children.1, 2 The functional presentation of the disorder is heterogeneous, but involves deficits in gross and/or fine motor skills.1

Existing studies show that children with DCD are at greater risk for a number of physical and mental health-related problems, including poor physical fitness3, 4 (particularly cardiorespiratory fitness (CRF)5, 6), overweight and obesity,7 and depression and anxiety.8 Studies have also shown that children with DCD are less physically active than their typically developing peers.9, 10

Lower levels of CRF are one of the more concerning health outcomes associated with DCD.4 Improving CRF produces physiological adaptations that improve the efficiency of the respiratory and circulatory oxygen transport system, and these adaptations confer numerous health benefits, including reduced risk for cardiovascular disease and reduced all-cause mortality.11

The activity deficit hypothesis describes connections between poor motor coordination, physical inactivity and CRF (as well as overweight/obesity) as a negative feedback loop.4, 5, 9 It is hypothesized that poor motor coordination discourages children from participating in physical activities, which negatively affects the development of physical fitness and increases the risk for unhealthy weight gain. Poor health-related fitness, in turn, leads to further reductions in physical activity.4 In this way, poor motor coordination becomes a risk factor for negative health outcomes later in life.12

Evaluating the activity deficit hypothesis requires longitudinal data with repeated assessments of physical activity (PA) and fitness. Few studies have tracked changes in CRF in children with DCD,3, 13, 14 and these studies are limited by small samples3, 14 and/or by relatively short follow-up periods.3, 13 More importantly, no attempts have been made to test the activity-deficit hypothesis with these data. If an activity deficit is responsible for poor fitness among children with DCD, then a measure of physical activity should explain a substantial part of the association between motor proficiency and fitness.

In a previous paper, we examined changes in CRF over a 2.5-year period, and showed that both boys and girls with possible DCD (pDCD) have poorer fitness levels than typically developing children.13 Since this analysis was conducted, data collection for this study cohort has been completed. The final dataset includes an additional 2 years of follow-up, making it possible to track CRF from age 9 to age 14. In this report, we also examine the associations between self-reported participation in organized and active free play and CRF in children with and without pDCD.

Section snippets

Methods

The Physical Health Activity Study Team (PHAST) project was a longitudinal prospective cohort study of children designed to examine change over time in PA and health-related fitness in children with and without poor motor coordination. Details of the design have been described in previous publications.10, 15 Data collection commenced during the 2004–2005 school year. The target population was all children in the fourth grade who were enrolled in the public school system in the Niagara region of

Results

Descriptive statistics are presented in Table 1. At baseline, there were 97 children (5.0%) with pDCD. Of these, 56 (58%) were girls and 41 (42%) boys. As the study was an open cohort, the number of children with pDCD rises to 103 when participants joining in later waves are included. The analysis included a total of 12,338 follow-ups on 2117 children.

The number of boys and girls in the cohort were roughly equal, and the average age of children at the start of the study was 9.9 years (SD = 0.4).

Discussion

Performance on the shuttle run in our sample was very similar to that reported in a recent meta-analysis,23 and showed closely comparable patterns of age and sex differences: The mean stage reached increased for both boys and girls, while body mass-scaled VO2 peak decreased. Consistent with previous work reporting on smaller samples, our results also show that children with pDCD, regardless of sex, have poorer CRF than typically developing children.6, 24 Moreover, differences in CRF between

Conclusion

The purpose of this study was to evaluate the activity deficit hypothesis in a large cohort of children by testing whether levels of measured physical activity accounted for poor fitness among children with pDCD. Our results show that they do not: Although we have suggested possible explanations for the absence of effect modification by PA in our models, we have found no good evidence that PA explains overall group differences in CRF. Although this difference increases with age, it is

Practical implications

  • Children with motor coordination problems have poorer cardiorespiratory fitness than typically developing children.

  • This fitness difference is present at age 9 and increases somewhat through age 14.

  • The gap in fitness is not explained by differences in self-reported physical activity at these ages.

Acknowledgements

Financial support for this study was provided by the Canadian Institutes of Health Research, Award No. 66959; Dr. Cairney is supported by an endowed professorship through the Department of Family Medicine at McMaster University.

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