Dawne Larkin

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

Physical activity, physical fitness and motor competence are important health‐related constructs. However, the relationship among them, particularly for children and adolescents, is still unclear. In this study, motor competence (measured by the McCarron Assessment of Neuromuscular Development), pedometer‐determined physical activity and physical fitness (aerobic fitness, muscle strength, muscle endurance, flexibility and body composition) were examined in a cohort of 1585 adolescents (771 girls, 814 boys) of mean age 14.06 years. Significant gender differences were observed for all measures except motor competence. Apart from hip and shoulder flexibility, males outperformed females. For both males and females, motor competence was associated with all fitness measures, physical activity was associated only with aerobic fitness and aerobic fitness was associated with physical activity, motor competence, BMI and chest pass. Among males, aerobic fitness was also associated with all other fitness tests. The correlations were, in general, moderate to weak. The results challenge the current focus on physical activity rather than physical fitness as the preferred intervention.

Activities of daily living in children with developmental coordination disorder: Dressing, personal hygiene, and eating skills

In order to understand how age, culture, and problems in motor coordination impact the performance of activities of daily living, we used focus groups and in-depth interviews with Australian and Canadian parents to examine activities of daily living of younger (5-7 years of age) and older (8-9 years of age) children with and without DCD. By comparison with their typically developing age group, children with DCD had more difficulty with dressing, personal hygiene, and eating skills. Difficulties with postural control and fine-motor skills were reported to contribute to poorer performance of activities of daily living. As expected, competence in the performance of activities of daily living improved in the older children with and without DCD and there were few differences in the performance of daily living tasks between typical children in Australia and Canada. Overall, the motor difficulties of children with DCD had a significant impact on performance of a wide range of daily activities.

Physical fitness differences in children with and without motor learning difficulties

Children with motor learning difficulties (MLD) tend to be less physically active than their coordinated peers and one likely consequence is a reduced level of physical fitness. In this study, 52 children with MLD, aged 5 to 8 years, were compared to 52 age‐ and gender‐matched control children across a range of health and skill related fitness components. Analyses of variance revealed significantly lower scores in the group with MLD on the tests for cardiorespiratory endurance, flexibility, abdominal strength, speed and power than the control group. Furthermore, the group with MLD had a significantly higher Body Mass Index (BMI). These findings have implications for educators and allied health professionals working with this age group. Programmes need to teach children with movement difficulties to perform tasks used in fitness assessment and also to work on the development of physical fitness.

The associations between physical activity, screen time and weight from 6 to 14 yrs: the Raine Study.

To examine the strength and direction of the relationship between physical activity level, screen use and BMI in a cohort at ages 6, 8, 10 and 14 yrs as part of a prospective longitudinal cohort study. The sample comprised 1403 males and females who participated in the follow-up survey at 14 yrs of age between 2003 and 2005. Exploratory structural equation modelling was used to examine the interrelationships between physical activity level, BMI and screen time at 6, 8, 10 and 14 yrs. Predictors of BMI at 6, 8, 10 and 14 yrs explained 1.3, 76.1, 80.1 and 73.1 percent of the variances, respectively, with previous BMI the largest predictor [χ(2)=43.082, df=36, p=194]. Increased screen time predicted higher BMI and lower physical activity at 8 and 10 yrs but not 14 yrs. At 14 yrs, physical activity predicted BMI. Sedentary patterns of behaviour in early childhood were predictive of later and concurrent obesity, whereas physical activity was predictive of obesity in adolescence. Different intervention targets are required for children and adolescents.

Laterality, motor asymmetry and clumsiness in children

Abstract This study explored relationship between clumsiness, laterality and performance asymmetry with particular emphasis on the lower limbs. Coordination levels of two clumsy groups and two coordinated groups (40 per condition) in the age bands of 5 to 6 years and 8 to 9 years were identified using the McCarron (1982) Assessment of Neuromuscular Development. A laterality battery based on Porac and Corens (1981) Self-Report Inventory was administered behaviourally to identify patterns of laterality across hand, foot, eye and ear. Preference assessment preceded measures of performance of the left and right leg for the stationary repetitive hop, one-leg balance and one-foot tapping. There was a higher incidence of left-eyedness in the clumsy sample which contributed to their reduced degree of laterality across all indexes. The clumsy group had relatively larger differences between the legs for the hop and balance tasks. Despite relatively smaller performance differences, the older coordinated group were better able to match preference and performance.

Physical activity measurement methods for young children: A comparative study

Many behavior patterns that impact on physical activity experiences are established in early childhood, therefore it is important that valid, reliable, and feasible measures are constructed to identify children who are not developing appropriate and healthy activity habits. In this study, measures of physical activity derived by accelerometry and pedometry are compared with direct observation of 5- and 6-year-old children (N = 24). The children were monitored for 30 min over 5 consecutive days during a free play session in their preprimary setting. The results for all measures were significantly correlated. When compared to direct observation, the coefficient of determination indicated that the pedometer (R2 = .81) was able to more accurately predict all levels of physical activity compared to the accelerometer (R2 = .59). When the children were grouped into low, moderate, wand high activity levels using observation, the pedometer data were better able to separate the groups than the accelerometer data. These findings indicate that the pedometer is a better measure of free play physical activity in 5- and 6-year-old children compared to the accelerometer.

Increased associated movements: Influence of attention deficits and movement difficulties

This study was designed to examine whether increased associated movements (AMs) reflect motor difficulties or the symptoms associated with attention disorders. Four groups of male children (N=51) aged 6-8 years participated: Group 1 consisted of 13 children diagnosed with developmental coordination disorder (DCD); Group 2 consisted of 13 children diagnosed with attention deficit hyperactivity disorder (ADHD); Group 3 consisted of 10 children diagnosed with co-occurring DCD and ADHD, and Group 4 was a control sample of 15 children, with no known movement or attention difficulties. Various AM tasks were selected from established assessments and previous research to measure AM severity. The results supported the hypothesis that increased severity of AMs reflect movement difficulties with children in the DCD and DCD/ADHD groups displaying significantly more AMs than children in the ADHD and control groups (p<.001). No differences were found between the ADHD only and control groups (p=.67) or the DCD and DCD/ADHD groups (p=.81) suggesting that AM severity is not influenced by the neurodevelopmental symptoms associated with ADHD.

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.

Intra-individual variation in children's physical activity patterns: Implications for measurement

Childrens physical activity (PA) patterns change from day to day. This intra-individual variability affects precision when measuring key physical activity and sedentary behaviour variables. This paper discusses strategies used to reduce the random error associated with intra-individual variability and demonstrates the implications for assessing PA when varying number of days are sampled. Self-reported data collected on two hundred and ninety eight 13-14-year-olds were used to compare estimates of PA and sedentary behaviour derived from between 1 and 7 days of recall data. Large intra-individual coefficients of variation were calculated for physical activity level (14.5%), moderate-to-vigorous physical activity (83.4%), screen time (60.8%) and sleep (12.2%). While the magnitude of error associated with estimating means decreased as more days were sampled, the paper notes that depending on the nature of the research question being asked, sampling fewer days may yield sufficiently precise estimates. Therefore, researchers should conduct power analyses based on estimated inter- and intra-individual variability and sample size to determine how many days to sample when assessing childrens PA patterns.

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.