Validity of a Low-Cost, Commercially-Available Accelerometer During Free-Choice Physical Activity in a Controlled Environment in Children

Introduction: The purpose of this study was to test the relationship between accelerometer counts from a novel, low- cost physical activity monitor (Movband) and a previously- validated monitor (Actigraph GT1M) during two conditions of differing physical activity behavior in children. Methods: Twenty children (n = 10 girls) participated in 30 minutes of physical activity/sedentary behavior in a controlled gymnasium setting on two separate occasions: low activity and high activity. During each condition, children had free access to physical activities (e.g., obstacle courses, balls) and sedentary options (e.g., books, toys) while wearing the Movband and Actigraph accelerometers simultaneously to measure physical activity. To manipulate physical activity behavior, children were given access to an internet-connected tablet computer (Apple iPad) during the low but not the high activity condition. Children were 40% more physically active in the high versus the low activity condition. Results: There was a large, significant, positive association between the Movband and Actigraph (r = 0.91, p < 0.001) in the low activity condition. This was also true during the high activity condition, however the strength of the correlation (r = 0.77, p < 0.001) was weaker. Conclusion: The Movband could be considered a valid measure of physical activity behavior in children.