The Principal Investigator of this project has extensive experience using accelerometers in minority youth, and is Co-Director of the Human Measurement Core of the USC Center for Transdisciplinary Research on Energetics and Cancer (TREC) funded by NCI, which is responsible for physical activity measures across all TREC center projects. Accelerometer data for assessment of physical activity is one of the most prevalent measures (coupled with dietary data) used to evaluate energy expenditure6, 26, 27. However, most research involves the wear of a single accelerometer which does not yield truly accurate data 24. Therefore, in this project we propose to synchronize multiple accelerometery data sources to estimate energy expenditure more accurately28.