Validating Pedometer - based Physical Activity Time against Accelerometer in Middle School Physical Education

The purpose of this study was to validate physical activity time in middle school physical education as measured by pedometers in relation to a criterion measure, namely, students’ accelerometerdetermined moderate to vigorous physical activity (MVPA). Participants were 155 sixth to eighth graders participating in regularly scheduled physical education classes from a suburban public school. Physical activity levels were measured by Yamax pedometers and Actical accelerometers. Descriptive analyses were conducted to calculate steps per minute (SPM) for pedometers and time engaged in MVPA (TMVPA) and percentage of time engaged in MVPA (PMVPA) for accelerometers, respectively. Correlation analyses yielded that SPM were positively and significantly related to TMVPA and PMVPA. Additionally, the percentage of agreement and modified kappa between SPM and PMVPA were .45 and .24, respectively. In conclusion, pedometer-based SPM is a valid tool to survey physical activity time against accelerometers.