J Phys Act Health. 2019 Jun 27;16(7):512-517. doi: 10.1123/jpah.2018-0288.
The primary purpose of this study was to determine which physical activity (PA) opportunity elicits the most moderate to vigorous PA (MVPA) in after-school programs. This study used a 3-group cross-over design in which participants were exposed to 3 variations of activity structures: free play, organized, or a mixture.
PA was measured using ActiGraph GT3X+ accelerometers. All data were transformed into percentage of time spent sedentary or in MVPA. Repeated-measures mixed-effects models were used to examine differences in MVPA and sedentary among the 3 activity sessions. Participants included 197 unique children, aged 5-12 years, and were 53% male and 55% white.
Statistically significant differences were observed in the percentage of time boys spent in MVPA during free play and mixed compared with organized only sessions (35.8% and 34.8% vs 29.4%). No significant difference was observed in the percentage of time girls spent in MVPA during free play compared with organized or mixed (27.2% and 26.1% vs 26.1%). Both boys and girls experienced ∼10% less time sedentary during free play compared with the others.
Offering free play during PA opportunities can help children attain as much if not more MVPA compared with only offering organized, adult-led games.
本研究的主要目的是确定在课后活动中，哪种体育活动（PA）机会能产生最多的中等至剧烈强度体育活动（MVPA）。本研究采用 3 组交叉设计，参与者分别接触 3 种活动结构变化：自由游戏、组织游戏或混合游戏。
使用 ActiGraph GT3X+加速度计测量 PA。所有数据都转换为久坐或 MVPA 时间的百分比。采用重复测量混合效应模型来检查 3 种活动时段之间的 MVPA 和久坐时间的差异。参与者包括 197 名年龄在 5-12 岁的独特儿童，其中 53%为男性，55%为白人。
在男孩自由游戏和混合游戏中 MVPA 时间百分比与仅组织游戏相比，有统计学意义的差异（35.8%和 34.8% vs 29.4%）。在女孩的自由游戏中 MVPA 时间百分比与组织游戏或混合游戏相比，没有显著差异（27.2%和 26.1% vs 26.1%）。与其他两种游戏相比，男孩和女孩在自由游戏中久坐时间分别减少了约 10%。
在 PA 机会中提供自由游戏可以帮助儿童获得与仅提供组织的、成人主导的游戏一样多甚至更多的 MVPA。
