JMIR Publications

ABSTRACT

Background:

Emerging evidence suggests a positive association between relevant aspects of one’s psychological identity and physical activity engagement, but the current understanding of this relationship is primarily based on scales designed to assess identity as a person who exercises, leaving out essential aspects of physical activities (e.g., incidental and occupational physical activity) and sedentary behavior.

Objective:

The goal of this study is to evaluate the validity of a new physical activity and sedentary behavior identity scale (PA/SB identity scale) using two independent samples of U.S. adults.

Methods:

In study 1, participants answered 21 candidate items for the PA/SB identity scale and completed the International Physical Activity Questionnaire-Short Form (IPAQ-SF). Study 2 participants completed the same PA/SB identity items twice over a 1-week interval and completed the IPAQ-SF at the end. We performed factor analyses to evaluate the structure of the PA/SB identity scale, evaluated convergent validity and test-retest reliability (in study 2) of the final scale scores, and examined their discriminant validity using tests for differences in dependent correlations.

Results:

The final PA/SB identity measure was comprised of 3 scales: physical activity role identity (F1), physical activity belief (F2), and sedentary behavior role identity (F3), with high test-retest reliability. The F1 and F2 were positively correlated to each other, while both were negatively correlated with F3. Data from study 2 also demonstrate adequate discriminant validity.

Conclusions:

This study provided initial empirical evidence from two independent studies on the reliability and validity of the physical activity and sedentary identity scales for adults.