1. a Health and Human Performance Studies , University of Alabama , Tuscaloosa , AL , 35487 , USA
2. b Department of Health, Leisure, and Safety Sciences , University of Tennessee , Knoxville , TN , 37996-2710 , USA
3. c Macro International Inc. , Calverton , MD , 20705 , USA
4. d Department of Health Promotion and Kinesiology , University of North Carolina , Charlotte , NC , 28223 , USA