title: Testing multi-theory model (MTM) in predicting initiation and sustenance of physical activity behavior among college students.
abstract: BACKGROUND
  Most college students do not adequately participate in enough physical activity (PA) to attain health benefits. A theory-based approach is critical in developing effective interventions to promote PA. The purpose of this study was to examine the utility of the newly proposed multi-theory model (MTM) of health behavior change in predicting initiation and sustenance of PA among college students.
  
  
  METHODS
  Using a cross-sectional design, a valid and reliable survey was administered in October 2015 electronically to students enrolled at a large Southern US University. The internal consistency Cronbach alphas of the subscales were acceptable (0.65-0.92). Only those who did not engage in more than 150 minutes of moderate to vigorous intensity aerobic PA during the past week were included in this study.
  
  
  RESULTS
  Of the 495 respondents, 190 met the inclusion criteria of which 141 completed the survey. The majority of participants were females (72.3%) and Caucasians (70.9%). Findings of the confirmatory factor analysis (CFA) confirmed construct validity of subscales (initiation model: χ2 = 253.92 [df = 143], P < 0.001, CFI = 0.91, RMSEA = 0.07, SRMR = 0.07; sustenance model: χ2= 19.40 [df = 22], P < 0.001, CFI = 1.00, RMSEA = 0.00, SRMR = 0.03). Multivariate regression analysis showed that 26% of the variance in the PA initiation was explained by advantages outweighing disadvantages, behavioral confidence, work status, and changes in physical environment. Additionally, 29.7% of the variance in PA sustenance was explained by emotional transformation, practice for change, and changes in social environment.
  
  
  CONCLUSIONS
  Based on this study's findings, MTM appears to be a robust theoretical framework for predicting PA behavior change. Future research directions and development of suitable intervention strategies are discussed.
authors.affiliation: Department of Health, Physical Education, and Exercise Science, School of Allied Health Sciences, Lincoln Memorial University, Harrogate, TN, USA.
authors.forename: Vinayak K
authors.initials: VK
authors.lastname: Nahar
authors.affiliation: Behavioral & Environmental Health, School of Public Health, Jackson State University, MS, USA.
authors.forename: Manoj
authors.initials: M
authors.lastname: Sharma
authors.affiliation: Public Health Studies, School of Health and Applied Human Sciences, University of North Carolina Wilmington, NC, USA.
authors.forename: Hannah Priest
authors.initials: HP
authors.lastname: Catalano
authors.affiliation: Department of Kinesiology and Health Promotion, College of Education, University of Kentucky, KY, USA.
authors.forename: Melinda J
authors.initials: MJ
authors.lastname: Ickes
authors.affiliation: Department of Management, School of Business Administration, University of Mississippi, MS, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Johnson
authors.affiliation: Department of Health, Exercise Science & Recreation Management, School of Applied Sciences, University of Mississippi, MS, USA.
authors.forename: M Allison
authors.initials: MA
authors.lastname: Ford
keywords: College students; Exercise; Multi-theory model; Needs assessment; Physical activity