Construct Validation of a Tool to Measure Fear of Physical Activity and Exercise in Survivors of Breast Cancer-the FPAX-B

Background: The impact of fear on physical activity and exercise has not been measured in the breast cancer population. Objective: The purpose of this study was to establish psychometric properties of a tool that quantitatively measures the role of fear as a barrier to physical activity and exercise in survivors of breast cancer. Methods: Previous content validation yielded a scale of 23 items named the Fear of Physical Activity/Exercise Scale-Breast Cancer (FPAX-B). This study includes 345 breast cancer survivors who completed informed consent, demographic data, FPAX-B, Rapid Assessment of Physical Activity (RAPA), Tampa Scale for Kinesiophobia (TSK), and Epworth Sleepiness Scale (ESS) through an internet survey or post mail. The internal structure of the FPAX-B was examined using principal components exploratory factor analysis (EFA) and varimax rotation. Factors were identified by Eigenvalues > 1.0, Scree plots, and the number of loaded items. Results: Mean FPAX-B score was low at 8.7/68 (11.9), indicating low fear. The RAPA results indicated that participants were moderately active. Following EFA analysis, the final scale had 3 factors and 17 items, which explained 70.6% of the scale variance and were labeled by the principal traits of the loaded items post rotation. Reliability for the scale was high (α = .95), convergent validity with TSK was moderate (r = .53), and divergent validity with ESS was low (r = .11). Limitations: The participants who self-selected to be part of this study were active survivors several years posttreatment. Conclusions: The FPAX-B is a new tool to examine concerns impacting physical activity and exercise decisions of survivors of breast cancer. It has strong internal consistency and demonstrates evidence of acceptable construct validity.