This study will be investigating whether a theory-based physical activity intervention can maintain/improve moderate to vigorous intensity physical activity measured via accelerometry of new parents over the eight months of having a child compared to a control group of new parents.

Hypothesis: The theory-based condition will change salient underlying motives (theory of planned behaviour constructs) for physical activity. Health-related fitness and quality of life will also be higher for this condition in comparison to the control condition. (Note: improvements in both groups of mothers may occur due to recovery from pregnancy, but our hypotheses will still hold). All outcomes will remain significantly higher at eight months in the theory-based condition compared to the standard condition

Clearly the prevention of chronic disease through physical activity promotion is an important research area. Identifying critical life transitions in people's physical activity behaviours may illuminate the most opportune intervention apertures for chronic disease prevention. A substantive evidence base now indicates that parenthood is one of these critical transition points for physical activity decline. Our proposed study will examine whether a brief, theory-based, and cost-effective intervention can help maintain/improve the physical activity behaviours of new parents in their first eight months of the parenthood experience. The study represents the first couple-based physical activity initiative in the parenthood literature; prior research has only focused on mothers and has shown short-term changes in physical activity that return to baseline levels after approximately one month. In light of the potential for couples to provide important sources of social support for the other parent within the household, it would seem remiss not to consider parenting interventions that are directed and evaluated at the dyadic level. Furthermore, couple-based interventions in other populations and other health behaviour domains have been shown as more effective than individual-level intervention. The long-term impact of this study, if the results support our hypotheses, has utility to prevent or curb the decline of physical activity habits based on our findings. This research has the clear potential to be applied to population-level knowledge translation sources such as prenatal classes, physician offices, and other early parent learning/counselling avenues.

Parents will be measured at baseline (2 months post partum) with two assessment points at six weeks (3.5 months post partum) and three months (5 months post partum) and a final follow-up assessment six months later (8 months post partum). The content of the theory-based intervention was derived from the results of our prior CDA and SSHRC-funded longitudinal trial of new parents using the theory of planned behaviour to predict changes in physical activity, the content used in prior pilot-level studies that has already been successful in changing short-term physical activity in mothers 26-30, and the content of our current CIHR-funded study of physical activity goal planning.

Primary Research Question

1) Does the theory-based condition improve adherence to regular physical activity among new parents when compared to those in the control condition at eight months after the birth of their first child? Hypothesis: Adherence will be higher for parents in the theory-based condition in comparison to parents in the control condition after controlling for possible confounds. The adherence effect may wane over time from the initial measurement period of two months after the onset of parenthood but all outcomes will remain significantly higher at eight months.

Secondary Research Questions

1. Does the theory-based condition improve motivational, health-related quality of life, and health-related fitness outcomes among new parents when compared to those in the control condition at eight months after the onset of parenthood? Hypothesis: The theory-based condition will change salient underlying motives (theory of planned behaviour constructs) for physical activity because its basis is from the key results of our prior longitudinal trial of new parents. Health-related fitness and quality of life, will also be higher for this condition in comparison to the control condition, (footnote: improvements in both groups of mothers may occur due to recovery from pregnancy, but our hypotheses will still hold). All outcomes will remain significantly higher at eight months in the theory-based condition compared to the standard physical activity education group.

2. Can group differences among new parents with regard to these motivational, behavioural, and health-related fitness outcomes be explained through a mediation model?

   Hypothesis: The covariance of the assigned conditions (theory-based, standard) on adherence will be explained by changes in the salient underlying motives for physical activity (i.e., manipulation check). In turn, the covariance between these salient underlying motives and health-related outcomes will be explained by physical activity adherence among conditions.

3. Can motivational variables predict adherence? Do these differ by condition?

   Hypothesis: The approach will test Ajzen's 39 theory of planned behavior. Affective attitude and perceived behavioural control will predict intention, intention will predict adherence across conditions similar to our prior study with this population 41.

4. Is there a seasonal, initial physical activity status, mental health or gender difference across primary outcomes by assigned condition?

Hypothesis: No differences in gender or season are hypothesized based on our lack of evidence in the prior trial41, but these are exploratory research questions because there is limited research at present to make any definitive statement. The examination of whether the intervention affects maintenance or increases in baseline physical activity via stratification of baseline values will also be explored as will the assessment of baseline depression and anxiety.

Recruitment: We began feasibility recruitment and procedures last year in order to establish our protocol, and pilot our intervention material. Based on this feasibility study, participant recruitment is being achieved with both active (pregnancy class visits) and passive recruitment techniques (notice of research and poster). The active recruitment is being conducted through community organizations offering prenatal classes and programming for first-time parents. The project coordinator and research assistants associated with this project are the main point of contact for potential participants. Organizations are contacted by the research coordinator and asked if they are interested in giving 10 minutes of time (prenatal class, workshop).

Inclusion Criteria:

• Married or common law couples
• Living in Greater Victoria
• Expecting first child
• 18 years of age or older

Exclusion Criteria:

• younger than 18
• Expecting second or third child