Validity of a questionnaire to assess historical physical activity in older women.

Purpose: To compare historical physical activity recall to original physical activity questionnaires collected at four time points over a 17-yr period in postmenopausal women.

Methods: This study examined the recall of physical activity (PA) data collected as part of a clinical trial of a walking intervention and subsequent follow-up in 163 white postmenopausal women (74 +/- 4 yr). Physical activity levels were measured with a modified version of the Paffenbarger Physical Activity Questionnaire (1982, 1985, 1995, 1999) throughout the duration of the study.