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Physical activity in children linked to motor abilities
By LOIS BAKER
Contributing Editor
Boys and girls who have better motor abilities are more physically active and less likely to be sedentary than children with poorer coordination, research conducted at UB with children between the ages of 8 and 10 has shown.
Results of the study appear in the December issue of the journal Pediatrics.
While the finding may appear intuitive, few studies have used a valid assessment of motor proficiency in children and compared the outcomes with an objective measure of physical activity, according to Brian H. Wrotniak, lead author on the study.
"The primary question of this cross-sectional research was to determine if there is a relationship between how coordinated children were and their level of physical activity," said Wrotniak, who conducted the study while a doctoral student at UB in the departments of Social and Preventive Medicine and Pediatrics. He now is a postdoctoral fellow at The Children's Hospital of Philadelphia and University at Pennsylvania School of Medicine.
"We thought it made sense that if a child is more coordinated, he or she would be more physically active, but no other known study had examined this association using valid measures of physical activity and motor proficiency.
"Many children in the U.S. are less physically active than recommended," Wrotniak continued. "Because a physically active lifestyle can help prevent the development of chronic diseases like cardiovascular disease and obesity, it is important to understand ways to help children become more physically active and less sedentary. One potential way is to teach youth to improve the movement skills that serve as the foundation for common forms of physical activity."
The study involved 34 girls and 31 boys living in Erie County. To measure physical activity, the children wore a device called an accelerometer for seven days. An accelerometer is similar to a pedometer, but instead of counting steps, it records activity counts per minute and indicates the intensity of physical activity—sedentary, light, moderate and vigorous—and picks up small movements that a pedometer would miss.
Children's motor proficiency was determined using a test comprised of age-appropriate activities to assess running speed and agility, balance, bilateral coordination, strength, upper-limb speed and dexterity, response time and visual-motor control.
The results of the study showed that motor proficiency is associated positively with physical activity and related negatively to the percentage of time in sedentary activity in children. When this association was examined by quartiles of motor abilities, children in the highest quartile of motor proficiency were the most physically active, compared with children in the lower quartiles.
"It was particularly interesting that children in the highest quartile of motor proficiency had an average of 18 minutes per day more moderate-to-vigorous physical activity than youth in the lower quartiles," said Wrotniak. "If we could improve coordination in children in the lower quartiles, they may be more likely to increase their physical activity."
Although none of the children were overweight in this study, the findings from the research also indicated that children who were heavier were less physically active and had poorer motor abilities.
"This relationship may explain some of the reason for weight gain in some children," said Wrotniak. "That is, it could be that children who are not that coordinated avoid participating in physical activity as a coping strategy and this then leads to more sedentary activity and positive energy balance, which results in weight gain."
Based on these findings, potential skills to target in children include activities that involve running speed, agility, jumping, balance and visual motor skills, said Wrotniak. "Including these skills as part of a school physical-education curriculum may be important. Activities that are fun and developmentally appropriate that children at any level of motor ability can participate in would be the most relevant. This could include dance or aerobic classes geared toward youth; after-school physical activity such as running games, obstacle courses, jump rope or hop-scotch; swimming; and agility activities involving changes in direction, such as soccer or basketball.
"Starting early is best," noted Wrotniak, "because physical activity dramatically declines when children reach adolescence and because physical activity in childhood is associated with physical activity later in life."
He explained, however, that because this was a study of the behavior and habits of a cross-section of children and not an intervention with a specific group of children, it cannot be assumed from the results that improving motor proficiency would increase physical activity.
"It could be that just by being physically active a child improves his or her motor abilities," he said. "I think it is likely that physical activity and movement abilities are interrelated. Also, there are many other variables that could explain children's physical activities, such as access to playgrounds and physical-activity facilities, neighborhood safety and parental physical activity and support that were not assessed in this study. This is just one piece of the puzzle."
He suggested that studying children over time or through an intervention designed to improve motor abilities could provide more definitive results.
Additional contributors to the research, all from UB, were Leonard Epstein, UB Distinguished Professor in the Department of Pediatrics, School of Medicine and Biomedical Sciences; Joan M. Dorn, associate professor in the Department of Social and Preventive Medicine, School of Public Health and Health Professions; and psychology students Katherine Jones and Valerie Kondilis.
The research was funded in part by grants to Wrotniak from the American Physical Therapy Association and the Mark Diamond Research Fund at UB.