Does physical activity affect the predictive value of health-related fitness tests on walking difficulty?

BACKGROUND Low levels of physical activity (PA) and poor fitness tend to predict a decline in mobility. The current study investigated whether PA modifies the predictive value of health-related fitness (HRF) tests on difficulty in walking 2 km (WD). METHODS PA was assessed by self-reported questionnaires in 1990 and 1996. Subjects age 55 to 69 years and free of self-reported WD participated in assessment of HRF in 1996. Occurrence of WD was assessed by questionnaire in 2002 (n=537). RESULTS There were no statistically significant interactions between PA and HRF tests; thus, PA and HRF were both independent predictors of WD. Regardless of the PA level, the subjects in the poorest performing third in each HRF test had higher risk of WD than the subjects in the best performing third. CONCLUSIONS PA and HRF seemed to be independent predictors of WD, although the association of PA with WD was weaker than the association of HRF. Thus, PA did not modify the predictive value of HRF on WD.