ACKNOWLEDGMENTS
This study was supported by grants from the Back Neck and Other Joint Pain Research Group and Khon Kaen University. David Kaber’s work on this study was supported by a grant from the U.S. National Institute for Occupational Safety & Health (NIOSH) (No. 2 T42 OH008673-06). The opinions expressed in this paper are those of the authors and do not necessarily reflect the views of NIOSH