THE PHYSICAL ACTIVITY PATTERNS OF CHILDREN WITH DOWN SYNDROME DURING SCHOOL

written by Megan MacDonald¹ (corresponding author), Phil Esposito², Dale Ulrich²

Background
The obesity epidemic facing the nation is well-known. In fact, recent reports from the Whitehouse have clearly established health & well-being as a national priority (USDHHS, 2000). Health, as we know it, includes many aspects one of which is physical activity.

The physical activity patterns of children and youth with Down syndrome (DS) are not well known. DS is the most common genetic cause of intellectual disability, and occurs in approximately 1 in every 700 live births (CDC, 2011). Individuals with DS are at a higher risk for obesity, osteoporosis, musculoskeletal disorders and cardiovascular related health problems, all risk factors that can be improved with moderate bouts of physical activity (Barnhart & Connolly, 2007).

A significant portion of a child's day takes place in school, and physical activity occurs in different amounts throughout the school day both formally and informally. Better understanding how much physical activity occurs during school can help us, as physical educators, towards creating effective programs to increase in-school physical activity at different ages.

The purpose of this study is to understand the physical activity patterns of children and youth with DS during the school day across four different age groups.

Method
Children 8-18 years of age, with DS, were recruited through parent support groups in the state of Michigan (n= 71). Each child wore an Actical ® accelerometer for a period of seven days (see figure 1). The accelerometers recorded physical activity counts in 15 second intervals. Accelerometer data were cleaned based on the following criteria: 1) the monitor was worn for 10 hours per day 2) the monitor was worn for a minimum of four days and 3) one of the four days was a weekend.

Regular school days and regular school hours were selected from the physical activity count data and analyzed. Physical activity was grouped into the categories of sedentary, light and moderate, to vigorous based on the previously established and validated physical activity counts from accelerometer data (Payau, Adolph, Vohra, Zakeri, & Butte, 2004).

Sedentary activity was coded if physical activity counts were less than 25, light activity was coded if physical activity counts were between 25-375, and moderate to vigorous physical activity was coded if physical activity count was above 375 (all counts were based on 15 second intervals).

Four age groups were created: 8 and 9 years (n= 19), 10 and 11 years (n= 25), 12 and 13 years (n= 16) and 14 and 15 years (n= 11). A mixed-model analysis was performed across age groups and covered for the amount of time spent wearing the physical activity monitor while in school. Post-hoc bonferroni corrections were performed across each age group comparison.

Results
Significant differences existed across age groups in time spent in sedentary (p < 0.001), light (p < 0.001) and moderate to vigorous physical activity (p < 0.01). Post-hoc pairwise comparisons indicated that students with DS in the 14 and 15 year age group were spending more time in sedentary activity compared to the 8 and 9 year age group, and 10 and 11 year age group (p < 0.05).

Youth in the 14 and 15 year age group were also obtaining significantly less light activity than students falling in the 8 and 9 year and 10 and 11 year age group (p < 0.05), and obtaining significantly less moderate to vigorous physical activity compared to the 10 and 11 year old age group (p < 0.05).

In short, these results suggest that children are participating in more sedentary physical activity, and less moderate to vigorous physical activity as they age. The results suggest that daily averages are significantly different and less physically active than younger children who also have DS.

Conclusions
It appears that physical activity obtained in school decreases as children with DS get older. Youth who fall into the oldest age group of 14 and 15 years seem to be the most at risk for physical inactivity during school. In general sedentary behavior increases as light and moderate to vigorous physical activity decrease.

These results corroborate previous studies that have found lower levels of physical activity in adolescents when compared to younger children (Esposito, MacDonald, & Ulrich, in press; Troiano, 2007). Interventions focused on physical activity have the potential to act as a preventative measure in health related problems associated with DS. This study strongly supports the implementation of quality daily physical activity during school for all children and youth, especially those with DS.

¹ School of Biological & Population Health Sciences, Exercise & Sport Science Program, Oregon State University, Corvallis, OR

² Center on Physical Activity & Health in Pediatric Disabilities, School of Kinesiology, University of Michigan, Ann Arbor, MI

Megan MacDonald is an Assistant Professor of Movement Studies in Disability at Oregon State University. She received a PhD in Kinesiology from the University of Michigan in 2011.

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