Move-To-Improve (MTI) empowers teachers to increase physical activity in small classroom spaces. As grade level and class size increased, time spent in physical activity declined. In multivariate analysis, grade level was a significant predictor of activity, whereas class size was not. Given that academic pressures are stronger in third-grade classrooms than in kindergarten, teachers in older grades might feel that physical activity in the classroom could detract from academic instruction. Nevertheless, although these data indicate that the effect of MTI is greatest in younger classrooms, they demonstrate that the program can be effective in older grades as well. Additionally, these data suggest that MTI training is effective even for teachers with many students and crowded classrooms.
A number of classrooms in our sample lacked any systematic access to physical activity. Sixteen classrooms had no scheduled recess, and 12 had no scheduled PE. In these classrooms, as in others, MTI training significantly increased observed classroom-based activity. Training classroom teachers may be important to ensure that children receive some opportunity for movement during the school day.
On average, teachers trained in MTI implemented 3 minutes of physical activity several times during the school day. Only 2 studies have examined the effect of very brief bouts of activity on clinical outcomes in children. One compared the effects of moderate-to-vigorous activity lasting less than 5 minutes with bouts lasting more than 5 minutes in 2,754 children aged 6 through 19 and found no difference in cardiometabolic risk factors between children who gained most of their activity through 1 form over the other (22
). The other examined the effect of bout length on overweight in 2,498 children aged 8 through 17 and determined that physical activity that took place in bouts lasting longer than 5 minutes conferred some benefits in overweight status over sporadic activity lasting less than 5 minutes (23
). To the best of our knowledge, no one has studied the effects of these bouts on children's physical activity behaviors as they age. The state mandates for PE do not establish minimum lengths of activity bouts; instead, they only specify the total number of minutes per week required. Likewise, both CDC and the Institute of Medicine recommend that children obtain 60 minutes of activity per day but make no requirements for bout length. The primary goal of the MTI program is to support elementary schools in their efforts to meet the state's mandate of 120 minutes of PE per week, and this evaluation demonstrates that MTI can be an effective strategy to increase compliance with these regulations. Additional program efforts will encourage teachers to implement MTI activities for longer bouts at a time.
Given the size of many urban school districts, interventions that require substantial investments in individual schools are not cost-effective. Programs that require ongoing technical assistance, refresher trainings, and continual support cannot be sustained in a school system as large as the NYC DOE. With nearly 800 elementary schools and an estimated 14,000 kindergarten through third-grade teachers serving more than 478,000 students in the NYC public school system, the MTI program represents a model intervention that can be successfully implemented, sustained, and adopted in large urban districts. Indeed, from its inception in fall 2009 through spring 2012, the MTI program has trained more than 4,300 teachers from approximately 500 elementary schools in the city's 5 boroughs.
This study had several limitations. First, the only schools eligible for participation in this evaluation were those that had participated in MTI. Because these schools elected to participate in a physical activity training program, they may be more likely to implement the program than the overall population of NYC schools. Second, because we compared trained and untrained teachers from within the same school, untrained teachers may have learned about MTI from their trained counterparts and began implementing activity on their own. However, this would have decreased our likelihood of finding a difference in physical activity time. Third, although trained teachers were randomly selected, untrained teachers were not. These teachers might not have been representative of all untrained teachers. Fourth, observed classroom teachers may have felt compelled to demonstrate more physical activity than they would usually provide during a school day. Although this pressure was presumably similar for trained and untrained teachers, trained teachers may have been more capable of leading fitness activities because of their MTI training. Fifth, observations were completed for only 1 school day when no PE class was scheduled. These data, then, cannot be extrapolated to determine what teachers would do on a day with a scheduled PE period. Sixth, 26% of the schools approached to participate in this study refused. Thus, schools that agreed to participate may have been a biased sample that was more likely to use fitness breaks compared with the overall NYC public school population. Finally, because data collectors were recording observed activity time, slight measurement errors may exist in the amount of time observed. However, the amount of time separating levels of physical activity in trained and untrained classrooms was so significant that measurement errors would not erase these differences.
Teachers were trained in MTI from February through May 2010 and were observed 6 months later, from October to December 2010. Also, because of issues with the MTI program's equipment vendor, most teachers trained in MTI in spring 2010 had not received their MTI equipment by the end of the evaluation. Despite these circumstances, 99% of trained teachers successfully incorporated MTI lessons into their classrooms the following school year, suggesting that MTI training has long-lasting effects.
Despite these limitations, to our knowledge, this is the largest observational evaluation of its kind. It demonstrates that MTI training increases physical activity time for students in the classroom setting. This intervention, requiring only a 1-time training with no follow-up, is feasible for large, urban school districts where time-intensive interventions are financially impossible. Giving classroom teachers the skills to implement PE is an effective approach to increasing physical activity for elementary school students.