Refinement of the Habitual Physical Activity Index for use with American adults.

The relationship between physical activity and health outcomes makes the assessment of physical activity important to many health professionals. Numerous physical activity questionnaires exist but none is tailored to the assessment of physical activity in cardiac patients. Ideally, a questionnaire should be appropriate for both healthy individuals and those with cardiac disease to allow comparison of epidemiologic and intervention research. The purpose of this research is to adapt and validate an existing physical activity questionnaire for use with healthy individuals and those with coronary artery disease. The Habitual Physical Activity Index (HPAI) is an easy to administer questionnaire developed in the Netherlands by Baecke, Burema, and Frijters (1982). The factorial validity and alpha internal consistency of the HPAI were examined to evaluate its potential for use in assessing physical activity of hospitalized cardiac patients in the U.S. The sample was 213 cardiac patients. A factor analysis produced a meaningful two-factor solution that differed from the original Dutch results. This suggested the HPAI should be modified for use with American adults with cardiac disease. New items were generated and added to the HPAI. The modified HPAI was tested using classical testing theory and generalizability theory. Stability estimates are high and relative generalizability acceptable. However, the absolute generalizability estimates indicate that the addition of new items to the HPAI could improve its use for absolute decision making.