An objective assessment of children's physical activity during the Keep It Moving! after-school program.

Background: After-school programs may provide valuable opportunities for children to accumulate healthful physical activity (PA). This study assessed the PA of third-, fourth-, and fifth-grade children in the Keep It Moving! (KIM) after-school PA program, which was implemented in an ethnically diverse and low socioeconomic status school district in Colorado Springs, Colorado.

Methods: The PA of KIM participating children (N = 116) at 4 elementary schools was objectively assessed using ActiGraph accelerometers and the System for Observing Fitness Instruction Time (SOFIT). Linear mixed-effects models or generalized linear mixed-effects models were used to compare time spent in sedentary (SED) behaviors, light PA (LPA), moderate PA (MPA), vigorous PA (VPA), and moderate-to-vigorous PA (MVPA) between genders and weight status classifications during KIM sessions.

Results: Children accumulated 7.6 minutes of SED time, 26.9 minutes of LPA, and 22.2 minutes of MVPA during KIM sessions. Boys accumulated less SED time (p < .05) and LPA (p = .04) than girls, but accumulated more MPA (p = .04), VPA (p = .03), and MVPA (p = .03). Overweight/obese children accumulated more LPA (p = .04) and less VPA (p < .05) than nonoverweight children. SOFIT data indicated that children spent a considerable proportion of KIM sessions being very active (12.4%), walking (36.0%), or standing (40.3%).

Conclusions: The KIM program provides opportunities for disadvantaged children to accumulate substantial amounts of MVPA (>20 minutes per session) in an effort to meet current PA guidelines.