Reproducibility and Validity of a Self-Administered Physical Activity Questionnaire for Male Health Professionals

We assessed the reproducibility and validity of a self-administered physical activity questionnaire used in a prospective study of 51,529 men. The questionnaire was administered by mail twice to 238 participants 2 years apart. During this interval, the participants completed a past-week recall and a 1-week activity diary at four times corresponding to different seasons throughout a year. Also, a step test was taken by a subset of the study...