Evaluation of the Accuracy of a Triaxial Accelerometer Embedded into a Cell Phone Platform for Measuring Physical Activity
|C U Manohar1, S K McCrady2, Y Fujiki3, I T Pavlidis3 and J A Levine2*|
|1Case School of Medicine, Case Western Reserve University, Cleveland OH 44106|
|2Endocrine Research Unit, Mayo Clinic, Rochester MN 55905|
|3Department of Computer Science, University of Houston, Houston TX 77004|
|Corresponding Author :||James A. Levine
Endocrine Research Unit
Mayo Clinic, Rochester MN 55905
E-mail: [email protected]
|Received November 14, 2011; Accepted December 14, 2011; Published December 20, 2011|
|Citation: Manohar CU, McCrady SK, Fujiki Y, Pavlidis IT, Levine JA (2011) Evaluation of the Accuracy of a Triaxial Accelerometer Embedded into a Cell Phone Platform for Measuring Physical Activity. J Obes Weig los Ther 1:106. doi:10.4172/2165-7904.1000106|
|Copyright: © 2011 Manohar CU, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.|
Background:Physical activity is important in health and weight management. Several cell phone platforms integrate an accelerometer onto the motherboard. Here we tested the validity of the cell phone accelerometer to assess physical activity in a controlled laboratory setting.
Methods: 31 subjects wore the cell phone on their waist along with the validated Physical Activity Monitoring System (PAMS) with different body postures and during graded walking. Energy expenditure was measured using indirect calorimetry. 11 subjects also wore the iPhone at different locations such as arm, hand, pant pocket, etc.
Results: The cell phone accelerometer was accurate and precise compared to the PAMS, with an intra-class correlation coefficient (r2> 0.98). The cell phone accelerometer showed excellent sequential increases with increased in walking velocity and energy expenditure (r2>0.9).
Conclusion:An accelerometer embedded into a cell phone was accurate and reliable in measuring and quantifying physical activity in the laboratory setting. Data from free-living users shows promise for deployment of a comprehensive integrated physical activity promoting and weight loss platform using such mobile technologies.