Background:

Longitudinal patterns in the development of physical activity (PA) and potential causal relationships between parent and child PA are examined.

Methods:

Autoregressive models were used to examine bidirectional prospective paths between parent and child PA in a longitudinal sample of 351 Anglo and Mexican American families. PA was assessed independently in children and parents over a 13-y period.

Results:

There was little evidence for a causal path from mother PA to child PA.

Conclusions:

Modeling does not appear to be the primary mechanism by which parents influence children’s PA behavior. Studies examining relations between parent and child behaviors should not rely on a single respondent for assessing both parent and child PA or on cross-sectional correlational data to make unidirectional causal inferences about determinants of child PA.