ObjectivesThe main purpose of the study was to assess the validity between the Fitbit and ActiGraph GT3X+ accelerometer. The specific aims were to determine the: (1) concurrent validity between the various models of the Fitbit and the GTX3+ accelerometer as the criterion measure for: number of steps and active minutes averaged over a single-day and 7-day period; (2) validity of the two devices with the International Physical Activity Questionnaire (IPAQ) for the number of daily active minutes performed.MethodsFifty-three subjects wore a Fitbit and ActiGraph concurrently for 7 days. Data were analysed using correlation coefficients, t-tests to assess mean comparisons and Bland-Altman plots to determine agreement between the Fitbit and the ActiGraph.ResultsThe correlations between the Fitbit and ActiGraph for steps per day and per 7 days were r=0.862 and 0.820, respectively with significant mean differences between both devices. Bland-Altman analyses revealed agreement between the Fitbit and the ActiGraph for 7-day active minutes only. The correlations between the Fitbit and ActiGraph for active minutes per day and per 7 days were r=0.695 and r=0.658, respectively, with no significant mean differences between both devices. No significant correlations were found between the IPAQ and the other two devices.ConclusionsThe data produced by the Fitbit were consistent with the ActiGraph when the means of each device were compared over the 1-day and 7-day time periods. However, Bland-Altman analyses revealed that the Fitbit agreed with the ActiGraph when used to measure physical activity levels over a 7-day span only.

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Homeschool children showed significantly lower levels of both abdominal and upper body muscular fitness compared with their age and gender matched public school peers but no difference in cardiorespiratory fitness.

Homeschooling is a growing trend in the USA and abroad with both reported consequences and benefits to youth physical health. The purpose of this study was to examine whether changes in youth physical health could be related to the number of years a student spends in homeschool. Body composition (body mass index and body fat), muscular fitness (lower extremity, abdominal and upper extremity) and cardiorespiratory fitness (Progressive Aerobic Capacity Endurance Run) were assessed in 211 youth ages 5–17. Data analysis showed weak or non-significant relationships between years in homeschool and all aspects of youth physical health. Time spent in homeschool is weakly or not at all related to multiple aspects of youth physical health. Parents and policy makers should not be concerned with detrimental physical health effects of homeschooling on youth.

Almost half of elementary school-aged homeschool children showed increased risk for CVD and need regular assessment of central adiposity.