Measuring the Processes of Change From the Transtheoretical Model for Physical Activity and Exercise in Overweight and Obese Adults.

PURPOSE

This study aimed to test three factorial structures conceptualizing the processes of change (POC) from the transtheoretical model and to examine the relationships between the POC and stages of change (SOC) among overweight and obese adults.

DESIGN

Cross-sectional study.

SETTING

This study was conducted at the University Hospital of Montpellier, France.

SUBJECTS

A sample of 289 overweight or obese participants (199 women) was enrolled in the study.

MEASURES

Participants completed the POC and SOC questionnaires during a 5-day hospitalization for weight management.

ANALYSIS

Structural equation modeling was used to compare the different factorial structures.

RESULTS

The unweighted least-squares method was used to identify the best-fit indices for the five fully correlated model (goodness-of-fit statistic = .96; adjusted goodness-of-fit statistic = .95; standardized root mean residual = .062; normed-fit index = .95; parsimonious normed-fit index = .83; parsimonious goodness-of-fit statistic = .78). The multivariate analysis of variance was significant (p < .001). A post hoc test showed that individuals in advanced SOC used more of both experiential and behavioral POC than those in preaction stages, with effect sizes ranging from .06 to .29.

CONCLUSION

This study supports the validity of the factorial structure of POC concerning physical activity and confirms the assumption that, in this context, people with excess weight use both experiential and behavioral processes. These preliminary results should be confirmed in a longitudinal study.