Influence of Parental Physical Activity and Sedentary Behavior on Young Children: Considering Time Together.

: Parents are key role models for their young child's physical activity (PA) and sedentary behavior. This study examined the relationship between parents and their young child's PA and sedentary behavior considering whether the parent and child were together (present) or apart. : Parent and child dyads ( = 26) wore accelerometers for 10 days and recorded times when they were present or absent from their young children (parental presence) in an online daily diary. Hourly data for PA and sedentary behavior of both the parent and young child were coded for parental presence. Multilevel modeling was used to predict child behavior (sedentary, light PA, and moderate to vigorous PA) using the respective parent behavior, the presence of the parent, and the interaction between parent behavior and presence. : The interaction between presence and parent behavior predicted the respective child behavior ( < .05). Parents' behavior was positively related to their young child's behavior when they were together, but the relationship was not present (moderate to vigorous PA) or weaker (sedentary behavior, light PA) when apart. : Being active alone was not sufficient for a parent's PA to relate to their young child's PA, but rather being active in the presence of their child was important for young child's PA.