Efficacious interventions to promote long-term maintenance of physical activity are not well understood. Engineers have developed methods to create dynamical system models for modeling idiographic (i.e., within-person) relationships within systems. In behavioral research, dynamical systems modeling may assist in decomposing intervention effects…

We assessed the factor structure of a revised version of the Exercise Imagery Inventory (EII; Giacobbi, Hausenblas, & Penfield, 2005), second-order interrelationships for cognitive and motivational forms of mental imagery, and associations with exercise behavior and barriers self-efficacy. A convenience sample of 358 (M age = 20.55 years, SD =…

The purpose of this study was to evaluate perceptions of quality of life after a 4-month progressive resistance training program for individuals with multiple sclerosis (MS). A second purpose was to examine participants' views about factors that facilitated or impeded exercise behavior. Qualitative interviews were conducted with eight females…

One aspect of construct validity is the extent to which the measurement properties of a rating scale are invariant across the groups being compared. An increasingly used method for assessing between-group differences in the measurement properties of items of a scale is the framework of differential item functioning (DIF). In this paper we…

The factorial and construct validity of the Exercise Imagery Inventory (EII) were assessed with 3 separate samples of participants. In Phase 1, a 41-item measure was administered to 504 undergraduate students. Exploratory factor analysis supported a 4-factor model that explained 65% of the variance. In Phase 2, a 19-item measure was administered…