Stability and prediction of physical activity in 5-, 10-, and 28-year follow-up studies among industrial employees.

The aim of the study was to examine the stability of voluntary and household physical activity (PA) and to compare it with that of the use of the most common stimulants. The prospective cohort study comprised of follow-ups at 5, 10, and 28 years at baseline in 1973 in four plants of an industrial corporation in Finland. A systematic, non-proportional sample (n=902, age range 18-64 years) stratified for age, gender, and occupational status was drawn from the employees. Scores of PA were based on a questionnaire and interviews. Logistic regression models with proportional odds assumptions were counted. The 5-year stability (Spearman's rho) of PA time was 0.44 (PA intensity 0.44), the respecti…