The prevalence of child obesity has increased dramatically over the past three decades [1–3] and attenuating these rates is a high priority in Canada, not only from a population health perspective, but from the health care system’s economic perspective. Moreover, obesity tracks very closely from childhood to adolescence to adulthood [2, 4]. Six in ten obese children have at least one risk factor for cardiovascular disease, and an additional 25% have two or more risk factors . Co-morbidities, such as Type 2 diabetes and non-alcoholic fatty liver disease, once considered problems among adults, are now being reported at a greater frequency among youths [5–8]. The greater risk of health complications associated with early morbidity affects normal childhood development and quality of life. In addition, the long-term health care burden increases exponentially if we include the obesity-associated chronic co-morbid conditions. It has been projected that the current generation of children will be the first in modern history to see a shorter life-expectancy than their parents  and we know that once it has developed, obesity is very difficult to treat. Indeed, there are many critical periods for intervention over one’s lifespan; however, these findings underscore the importance of prevention early in life and recent mathematical modelling suggests that targeted interventions for young children (0 to 6 years) could yield considerable cost savings to the health care system .
Canadian surveillance data, using directly measured heights and weights gathered as part of the Canadian Community Health Survey, indicate that overweight and obesity exist in the preschool age group with 15.2% of children aged 2 to 5 years categorized as overweight and 6.3% as obese . Overweight children have higher risks for numerous health conditions and children who become obese before the age of 6 years are likely to be obese later in childhood . The negative trajectory continues as these children often remain overweight as adults . Physical inactivity is associated with increased risk of several chronic diseases including obesity and heart disease [5, 7] and we know that only 7% of Canadian children between the ages of 6 and 19 years are meeting current physical activity (PA) guidelines . There is considerable evidence to indicate that reduced PA or increased sedentary behaviour are implicated in the etiology of childhood obesity and its associated conditions [6, 9, 10]. From the cardio-metabolic standpoint, the currently available evidence, albeit sparse, indicates that PA during the preschool years is associated with i) more desirable body composition variables [11–16] and ii) decreased cardiovascular risk factor status (i.e., lower total cholesterol , higher HDL cholesterol [17, 18], and lower sub-maximal heart rate during exercise ). Furthermore, motor development, or the process by which a child acquires movement patterns and skills, has also been shown to be positively associated with PA [20–22]. Early motor development is important as motor skills are a key factor in the likelihood of participation in various forms of PA during later childhood and adolescence [21, 23, 24].
PA is an acknowledged critical component of a healthy lifestyle and childhood experience as it has a meaningful impact on lifelong behaviour and health. Opportunities for PA and motor development in early childhood may, over the lifespan, influence the maintenance of a healthy body weight and reduce the risk of cardiovascular disease. It has been noted that children with low movement competence usually exhibit low PA levels [25, 26] and tend to be vigorously active less often, play less on large playground equipment, and spend less time interacting socially with their peers . Fundamental movement skills (e.g., catching, throwing, jumping, and running) are the essential building blocks for the acquisition of more refined and complicated skills that can be applied later in life, such as sporting, recreational, and physical activities [27–29]. However, movement skills will not develop to their full potential without opportunities to practice in environments that are stimulating and supportive [30, 31]. Butcher and Eaton  found that preschoolers’ movement competence was already influencing their PA levels and their PA choices.
There is a paucity of information on current trends in PA of preschool aged children in Canada, [32–34] and on the relationship between the ability of children to perform fundamental movement skills and prediction of PA . A 2012 systematic review was recently performed by Timmons et al.  to assemble and interpret the best available evidence for minimal and optimal amounts of PA needed to promote healthy growth and development in young children, including preschoolers. The underlying objective of this review was to help inform the development of evidence-based PA guidelines for this age group. The subsequently published guidelines recommend that “preschoolers (aged 3–4 years) should accumulate at least 180 min of physical activity at any intensity spread throughout the day, including a variety of activities in different environments, activities that develop movement skills, and progression toward at least 60 min of energetic play by 5 years of age” . A similar review  has also been published advocating that preschool-aged children should not be sedentary for more than 60 minutes at a time (less is better), except when sleeping, and guidelines have since been published  to this effect.
More than half of Canadian children between the ages of 6 months and 5 years are enrolled in some form of non-parental care, with a mean of 29 hours per week in this arrangement [40, 41]. Canada fails miserably on an international scale, in comparison to all other Organisation for Economic Co-operation and Development countries, with regard to treatment of our youngest and arguably most vulnerable citizens. According to the UNICEF Report Card, entitled The Child Care Transition, which focuses on the shift from parents raising children to out-of-home daycare, Canada was tied for last place in ensuring that this age group is getting high quality out-of-home care ; the key criticism of Canada was “lack of substantial public investment in education until children reach the age of 5”. This is a critical issue given that Canadian children are now spending more time in care outside of the home than ever before. Recognizing that the landscape of childcare in the developed world has changed dramatically over the last two decades, with the vast majority of children now attending some form of daycare during their early years, the preschool environment represents a focal point with great promise for health interventions. Several groups throughout the world have similarly identified the need to encourage and support PA within the preschool curriculum [43–45] and various teams are working towards evaluating potential solutions [46–51]. Uniquely, this Canadian three-arm RCT study is poised to explore not only changes in PA and anthropometrics, but motor skill development and quality of life, as well as changes to the daycare environment and to identify if the addition of a home component results in greater benefits.
We know that i) physical inactivity and poor fitness are independent risk factors for obesity, metabolic disorders, and cardiovascular disease in youth, ii) successful development of motor skills provides stimulus for ongoing PA engagement contributing to long-term health , and iii) PA levels track from early childhood to adulthood. Consequently, increasing children’s PA levels in the preschool years may alter their activity trajectory and increase the likelihood they will be physically active throughout development stages and into adulthood. The proposed intervention, Activity Begins in Childhood (ABC), is clinically relevant as it includes training workshops for daycare-providers focusing on the importance of PA and reducing sedentary behaviour, as well as strategies for implementing a variety of structured and unstructured physical activities to meet these objectives. This study will be able to address how viable the daycare setting is to promote PA in preschool-aged children and the possible incremental value of the home setting.