Examining Fifth-Grade In-School Physical Activity Patterns and How Many Days of Monitoring are Needed

PURPOSE: The purpose of the study was to examine in-school physical activity patterns among fifth-grade students residing in a Midwestern community. Variables observed were minutes of vigorous + activity, vigorous activity, moderate activity, easy activity and very easy activity along with steps and calories expended. A secondary purpose of this study was to determine the minimum number of days necessary to estimate mean physical activity levels, as both moderate-to-vigorous physical activity (MVPA) and steps per day, in fifth-grade students using objective physical activity monitors across two semesters. METHODS: Activity patterns were assessed during two school semesters, spring (N = 82 boys & 84 girls) and fall (N = 89 boys & 91 girls), from 10-12 year old fifth-grade students in four Midwestern elementary schools. Data was collected using wrist worn activity trackers. The devices were administered by teachers at the start of each school day and collected at the end of each school day for two consecutive weeks. Monitors measured MVPA and steps per day. Demographic and anthropometric data were also recorded (age, height, weight). All data was uploaded to the device website database and then collected by the primary researcher. Physical activity measures were surveyed and compared across the four different schools, semesters and genders. In the secondary analysis, steps and MVPA were examined, individually, with Cronbach’s alpha to determine how many days of measurement were needed to assess mean activity patterns. RESULTS: Average in-school MVPA for boys in the fall semester accounted for 79.17% of the daily recommendation (47.5 of the 60 minutes), for girls, in-school MVPA accounted for 69.14% of the daily recommendation (41.49 of the 60 minutes). During the spring semester, boys attained 74.39% or 44.64 minutes of their MVPA in-school, while girls attained 60.46% or 36.27 minutes of their MVPA in-school. Average steps measured in-school during the fall semester was 7,491 or 57% of total daily recommendation, average steps measured during the spring semester was 7,006 or 54% of the daily recommendation. The reliability analysis suggested that at least four days of measurement were needed to achieve an alpha of 0.80 for both steps (α = 0.825, 95% CI [0.777-0.865]) and MVPA (α = 0.839, 95% CI [0.795-0.87]) during spring collection. During the fall semester, at least four days were also necessary to achieve a reliability of 0.80 in steps (α = 0.803, 95% CI [0.751-0.846]) and MVPA (α = 0.811, 95% CI [0.761-0.852]). However, fall five-day activity patterns did exhibit greater variability than four-day activity patterns in both steps (α = 0.784, 95% CI [0.730-0.830]) and MVPA (α = 0.794, 95% CI [0.742-0.838]). CONCLUSIONS: Our results show that boys attained more steps and minutes of MVPA during both semesters of collection than girls. Both reached promising levels of activity in-school, allowing them optimal opportunity out of school to reach daily activity goals. These results also indicate that four-day activity monitoring protocols most accurately estimate the mean in-school physical activity patterns, steps and MVPA, in fifth grades students. It should be noted that the results indicate consistency was not improved by a fifth day of measurement in steps and MVPA during a five-day collection period