Objective Physical Activity in Children with Down Syndrome

Introduction Children with Down Syndrome (DS) have been demonstrated as being less active¹ and have showed lower levels of physical fitness² than children without DS. To date, the information regarding physical activity (PA) and persons with DS is limited and inconclusive. Therefore, the aim of this study was to assess objectively the levels of PA in children with DS comparing with children without disabilities.

Methods Forty two children (27 with DS) aged 12-18 years participated in this study. A uni-axial accelerometer (Actigraph GT1M) was used to register PA and steps of children during seven consecutive days. Accelerometer data to be valid had to present at least four days with eight hours of valid time. Minutes of valid time and minutes of sedentary, light, moderate, and vigorous physical activity were established by using the cut-offs proposed by Sirard³. Time of bouts (period of at least 5 min of consecutive moderate PA) and number of bouts were also measured. Differences between groups were established by 2-sided Student’s t test.

Results No significant differences between children with and without DS regarding sedentary, light, and vigorous times were observed neither in minutes (698.9 vs. 741.9; 49.7 vs. 49.4; 2.9 vs. 6.1 min/day) nor in the percentages of valid time (91.8 vs. 91.1; 6.5 vs. 6.1; 0.3 vs. 0.7 %) spent on those activities. However, children with DS engaged significantly less minutes in moderate (9.2 vs. 15.4 min/day) and moderate-vigorous physical activities (12.1 vs. 21.5 min/day) than their counterparts without DS. Similarly, the percentages of valid time (1.9 vs. 1.2 %) and (1.6 vs. 2.7 %) spent in those activities were lower. Moreover, lower time and number of bouts and steps were observed in the DS group compared with the control group (all p< 0.05).

Discussion Similar levels of sedentary and light PA were registered in children with and without DS; children with DS did not show a more sedentary behaviour than those without. Nevertheless, children with DS spent not only less total minutes of valid time participating in moderate and vigorous PA, but also lower percentage of their total valid time. Following ACSM guidelines children and adolescents should do at least 60 minutes of moderate PA 5 days a week; however, none of the two groups achieved these recommendations. Strategies aiming to increase moderate and vigorous activities in children with DS should be promoted as they may be at higher risk of developing diseases associated with physical inactivity such as osteoporosis or metabolic syndrome.

References 1. Sharav, T. et al. Clin Pediatr (Phila). 1992. 2. Fernhall, B. et al. Clin Exer Physiol. 2001. 3. Sirard, J.R. et al. Med Sci Sports Exerc. 2009.