Among adults, the association between regular physical activity and reductions in morbidity and mortality is well established . Whilst the body of research into the benefits of physical activity among children is not as extensive, there is growing support for the role of physical activity in bone health and emotional well-being , reduction in coronary heart disease (CHD) risk factors  and social and moral development and self esteem .
The transition from childhood to adolescence has been identified as a period of marked decline in physical activity [5–7], particularly amongst girls . Indeed, girls appear to be less physically active than boys across all age groups . Sex differences in the types and intensities of physical activity engaged in have also been reported, with boys undertaking more vigorous-intensity physical activity (VPA) , moderate- to vigorous-intensity physical activity (MVPA) , organized sport  and walking and cycling in the local neighbourhood  than girls. Understanding the influences on participation among girls is necessary to increase physical activity among this important target group.
It is useful to consider potential influences on behaviour under the guidance of theory. The Family Influence Model (FIM) [13, 14] purports that the home environment (consisting of parent/sibling beliefs, parent/sibling behaviour, and family functioning and interaction) influences a child’s perception of the home environment. This perception then leads to the development of specific beliefs which in turn is a primary influence on behaviour . In a physical activity context, the FIM has been used to explain the influence of the family environment on children’s MVPA , and posits that parents’ beliefs about their children’s MVPA is the basis for understanding family influence on children’s MVPA.
Constructs within the FIM, including factors within the proximal family environment, such as parent support, support from significant others, sibling physical activity and direct help from parents, have been consistently associated with adolescents’ physical activity . Parents’ provision of logistic support and explicit modelling has been associated with girls’ physical activity [15, 16], while among female adolescents, exercise knowledge and mothers’ modelling/support  have been identified as correlates of physical activity participation. Similarly, among inactive adolescent girls, support for physical activity from parents was a strong and consistent correlate of physical activity participation . Other constructs within the FIM, such as parents’ behaviour and family processes, have not been fully tested and family characteristics such as parenting style could be examined within this framework. Further, this model acknowledges the influence of socio-demographic factors on physical activity and the home environment , making it a useful tool for examining potential interactions between socio-demographic factors, parenting and physical activity.
Parenting style is a stable characteristic within the family environment , which has been associated with various health outcomes among adolescents [20, 21]. The literature identifies four main parenting styles, which are reflective of various degrees of demandingness (control) and responsiveness (support) [20–22]. Authoritative parents are considered responsive, nurturing, set clear expectations and explain the reasons behind these expectations . Authoritarian parents are firm and directive, relatively unresponsive, value obedience and exclude the child from decision making [20, 23]. Indulgent parents place few demands on the child and are child-oriented, responsive and nurturing, while neglectful parents provide relatively low support and control [20, 23]. Recent research suggests that authoritative feeding practices are associated with child consumption of fruit and vegetables [24, 25] and authoritarian parenting with risk of overweight among young children , although a recent review notes the lack of causal evidence . While preliminary data demonstrate an association between authoritative parenting and girls’ physical activity , few studies have comprehensively examined how parenting style influences physical activity, despite such studies being recognised as imperative . Further, the need for more longitudinal research in the area, employing a combination of self-report and objective measures, has been identified .
Given the important influence of parenting style on child and adolescent health behaviours and health, and the known associations between other aspects of the family environment (such as provision of support and direct help from parents) and physical activity, it is plausible that parenting style may influence adolescent physical activity. Further, socio-demographic characteristics previously associated with physical activity, such as educational attainment, may interact with parenting style to influence physical activity. The present study describes cross-sectional and longitudinal associations between parenting style and adolescent girls’ participation in organized sport, walking/cycling trips and objectively assessed MVPA and explores potential interaction with socio-demographic factors.