In 2000, based on a thorough review of 108 studies, Sallis et al reported that parent physical activity had been “frequently studied with considerable lack of consistency” as to its ability to predict child activity.13
Since then, 6 studies have demonstrated an association between parent modeling and physical activity among largely Caucasian adolescents,9-11, 19-21
and 3 studies examining the relationship found no association for African-American girls,22-24
the group at greatest risk of physical inactivity. In contrast, using a large, longitudinal dataset, we demonstrate the impact of perceived parent modeling on girls’ activity for both African-American and Caucasian girls. Girls who perceived that their parents exercised 3 or more times weekly were, on average, about 50% more active than girls with perceived sedentary parents. Our findings likely differ from prior studies in part because we used girls’ perception
of parental activity, while 2 of the 3 recent studies focusing on African-American youth relied on parents’ self-report of activity. In the present study, girls’ activity levels were more strongly influenced by girls’ perception of parental activity than by parent-reported activity. Because the correlation between girl- and parent-report of parent activity was slightly lower for African-American than for Caucasian girls, using girls’ perception of parent activity may be especially important for African-American youth.
Although parent-report might seem a more reliable indicator of parent activity than child-report, parents may over-report their physical activity levels, as is commonly seen with self-reported physical activity assessments.25
A child could, therefore, provide a more accurate report of a parents’ actual behaviors. Alternatively, girls may not observe their parents sufficiently to assess their parents’ activity. This is particularly likely to be problematic in studies including parents’ workday physical activity. Including workday activity may better capture total parental activity (Polley et al found that almost all activity reported by mothers occurred during their workday23
), but workday activity is less likely to influence children’s activity levels and less likely to represent parents’ values for physical activity. These results may provide potent incentive for parents to exercise, as health care providers can illustrate the link between a child’s perception of his or her parents’ activity and the child’s own health and well-being. Further, these findings have public health implications, suggesting interventions focused on parents’ activity might indirectly but significantly benefit the cardiovascular health of their children. The impact of parent modeling of activity (and dietary) behaviors might explain why involving the family in clinical interventions to reduce obesity in children leads to greater success.26
However, public health interventions to date have largely been aimed at increasing activity at the level of the child.
Developmental theory might suggest that parental influence decreases with time, but we found a stable relationship between parent and girl activity throughout adolescence, despite the increasing influence of psychosocial variables. This extends findings from Sallis’ early study among Latino and Anglo youth, suggesting that the impact of parent modeling on child activity did not decline over the 2-year period from 5th
We demonstrate the stability of the relationship over an 8-year period. Trost found that mothers’ activity in 5th
grade significantly predicted African-American girls’ vigorous physical activity in 6th
grade, but fathers’ activity did not.28
Our results would suggest that both parents’ activity levels play important roles and that the impact of father’s modeling increases over time. The decline in the association between girls’ activity and exercising with a parent over time may reflect the fact that the prevalence of exercising with parents decreased from 70% at age 9-10 to 32% at age 16-17 (data not shown). It is unrealistic to expect that girls will wish to exercise with their parents as they establish their independence and spend more time with peers. Thus, there may be a critical window for exercising with parents earlier, and parents’ habitual activity remains an important target for intervention throughout adolescence.
We found that the three parent modeling variables taken together explained approximately 5% of the variance in girls’ activity in any given year and overall, the models explained up to 28% of the variance in girls’ future activity. Parent education greatly attenuated the impact of parent modeling on girl’s physical activity in multivariate models, which is consistent with previous research reporting the negative influence of low socioeconomic status and potentially stressful home environment factors on physical activity.9, 22, 29
Families with fewer resources are less likely to access to facilities and time for physical activity. This underscores the critical need to address social disparities that potentiate health disparities, and the importance of creating environmental changes (through policy and urban planning, e.g.) that support families’ efforts to be active.30
Several limitations merit comment. Although girls with more active parents were, on average, 50% more active than girls with sedentary parents, the overall decline in activity overshadows this finding in later years and parent modeling explained a small percent of variance in girl’s activity in multivariate models. Data were self-reported, although using time-lagged predictor variables minimizes bias from girls’ current activity, potential confounding, and the effects of temporal trends. The influence of friends, an important contributor to girl activity, was not measured until Year 7 of the study. The model does not include logistical support, parental encouragement, or self-efficacy, all of which have been shown to relate to activity9, 10, 31-34
and to mediate the impact of parents’ activity on child physical activity.35
Their absence likely reduces our ability to explain more variance in girls’ activity. Nonetheless, previous research19
supports collapsing parental logistic support for physical activity with parent activity, likely because active parents appear to provide greater logistical support.36
The rapid decline in physical activity by age demonstrated among this diverse group of adolescent girls is of great concern. Our findings would suggest that it is not what parents say, but what children observe their parents doing. Culturally appropriate interventions to increase African-American parents’ activity, as part of a concerted public health effort, could address cardiovascular risk factors among both adults and children, potentially minimizing the growing disparities in cardiovascular health.