Detecting prolonged sitting bouts with the ActiGraph GT3X.The ActiGraph has a high ability to measure physical activity; however, it lacks an accurate posture classification to measure sedentary behavior. 
ActiGraph GT3X
Detecting prolonged sitting bouts with the ActiGraph GT3X.The ActiGraph has a high ability to measure physical activity; however, it lacks an accurate posture classification to measure sedentary behavior.  The aim of the present study was to develop an ActiGraph (waist-worn, 30 Hz) posture classification to detect prolonged sitting bouts, and to compare the classification to proprietary ActiGraph data.  Of all proprietary ActiGraph methods, only 150 cpm without LFE predicted the time in prolonged sitting bouts non-significantly different from the activPAL (bias ≤ 18 minutes/d).  To study the health effects of ActiGraph measured prolonged sitting, we recommend using the new algorithm. 
ActiGraph
The activPAL, a highly valid posture classification device, served as reference criterion.  The machine learning algorithm with optimal feature number to predict the time in prolonged sitting bouts (≥5 and ≥10 minutes) was searched and compared to the activPAL using Bland-Altman statistics.  Of all proprietary ActiGraph methods, only 150 cpm without LFE predicted the time in prolonged sitting bouts non-significantly different from the activPAL (bias ≤ 18 minutes/d). 
activPAL