5-Year Changes in Afterschool Physical Activity and Sedentary Behavior

Background:
The afterschool period holds promise for the promotion of physical activity, yet little is known about the importance of this period as children age.

Purpose:
To examine changes in physical activity of children aged 5–6 years and 10–12 years and their sedentary time in the afterschool period over 3 and 5 years, and to determine the contribution of this period to daily physical activity and sedentary behavior over time.

Methods:
Data from two longitudinal studies conducted in Melbourne, Australia, were used. Accelerometer data were provided for 2053 children at baseline (Children Living in Active Neighbourhoods Study [CLAN]: 2001; Health, Eating and Play Study [HEAPS]: 2002/2003); 756 at 3-year follow-up (time point 2 [T2]); and 622 at 5-year follow-up (T3). Light (LPA), moderate (MPA) and vigorous (VPA) physical activity were determined using age-adjusted cut-points. Sedentary time was defined as≤100counts/minute. Multilevel analyses, conducted in April 2012, assessed change in physical activity and sedentary time and the contributions of the afterschool period to overall levels.

Results:
Afterschool MPA and VPA decreased among both cohorts, particularly in the younger cohort, who performed less than half of their baseline levels at T3 (MPA: T1=24minutes; T3=11minutes; VPA: T1=12minutes; T3=4minutes). LPA also declined in the older cohort. Afterschool sedentary time increased among the younger (T1=42minutes; T3=64minutes) and older cohorts (T1=57minutes; T3=84minutes). The contribution of the afterschool period to overall MPA and VPA increased in the older cohort from 23% to 33% over 5 years. In the younger cohort, the contribution of the afterschool period to daily MPA and VPA decreased by 3% over 5 years.

Conclusions:
The importance of the afterschool period for children’s physical activity increases with age, particularly as children enter adolescence.