Maximizing children's physical activity using the LET US Play principles

Background: Staff in settings that care for children struggle to implement standards designed to promote moderate-to-vigorous physical activity (MVPA), suggesting a need for effective strategies to maximize the amount of time children spend in MVPA during scheduled PA opportunities. The purpose of this study was to compare the MVPA children accumulate during commonly played games delivered in their traditional format versus games modified according to the LET US Play principles. Methods: Children (K-5th) participated in 1-hour PA sessions delivered on non-consecutive days (summer 2014). Using a randomized, counterbalanced design, one of the six games was played for 20. min using either traditional rules or LET US Play followed by the other strategy with a 10. min break in between. Physical activity was measured via accelerometry. Repeated-measures, mixed-effects regression models were used to estimate differences in percent of time spent sedentary and in MVPA. Results: A total of 267 children (age 7.5. years, 43% female, 29% African American) participated in 50, 1-hour activity sessions. Games incorporating LET US Play elicited more MVPA from both boys and girls compared to the same games with traditional rules. For boys and girls, the largest MVPA difference occurred during tag games (+. 20.3%). The largest reduction in the percent of time sedentary occurred during tag games (boys -. 27.7%, girls -. 32.4%). Overall, the percentage of children meeting 50% time in MVPA increased in four games (+. 18.7% to +. 53.1%). Conclusion: LET US Play led to greater accumulation of MVPA for boys and girls, and can increase the percent of children attaining the 50% of time in MVPA standard.