Based on different theories of dynamic systems, children's development occurs through interaction between their genes, their physical and socio-emotional environment, and the amount and quality of earlier experiences. The amount of physical activity (PA) has been recognized as one very important mediator in supporting young children's physical growth and overall development. Moreover, PA has been shown to effect children's daily well-being and health [1Malina, et al. Maturation and Physical Activity  Human Kinetics IL: Champaign (2004). 

Cliquez ici pour aller à la section Références]. Children are physically active through their play. When children engage in physically active play, they use their whole body with all their senses and large muscles. Through playing children learn to feel their body, recognize their body shape, its profile and its strength. They also learn how to use it and move with it. Physically active play can include behavior such as reaching, crawling, hiding, running, jumping, throwing, and kicking. Children engaging in physical activity and play are exploring themselves at the same time, thereby stimulating their growth and overall development [2Pellegrini, et al. Physical activity play: the nature and function of a neglected aspect of play Child Dev 1998 ;  69 : 577-598 [cross-ref]

Cliquez ici pour aller à la section Références]. Because of multiple needs for children's development, it is important to recognize that the quality of PA, not only the intensity, matters. For example, balance skills are important to form the basis for the development of other motor skills, such like movement skills (e.g., running and jumping [3Gallahue, et al. Understanding motor development: infants, children, adolescents adults  New York: McGraw-Hill (2012). 

Cliquez ici pour aller à la section Références]). Movement skills increase the workload of children's metabolic system, which can be seen in the increasing intensity of PA. Increase in metabolic workload can be found through different PA measurements. Those results are typically reported by the intensity of PA, categorized as sedentary, light, moderate, or vigorous physical activity. Most PA research is based on these aspects. However, developmentally important neuromuscular loading, needed for balance skills, is hardly able to be recognized with current physical activity measurements. That's why there is an urgent need to find appropriate measurement tools for defining the appropriate amount and type of PA of young children [4Laukkanen, et al. Relationship between habitual physical activity and gross motor skills is multifaceted in 5- to 8-year-old children Scandinavian J Med Sci Sports 2013 ; [Ahead of print].

Cliquez ici pour aller à la section Références]. Earlier research has revealed that much of children's PA is mostly sedentary. Concern over the insufficient amount of developmentally appropriate PA has led to many national recommendations that seek to ensure children's normal growth and development. To ensure normal growth and development, there is a need to determine the keys to successful strategies for increasing children's daily physical activity levels in early childhood. In this presentation description of four Finnish intervention programs, analysis of previous systematic analysis, as well as recommendations to the practitioners will be presented.

Two sets of intervention projects–the family-based STRIP and InPact and the preschool-based Early Steps and HIPPA–have tried to determine the keys of successful strategies for increasing children's daily physical activity levels in early childhood.

One effective environment for young children is their own family. Children learn their lifestyle and values from their parents. Parents decide what their children are allowed to do and when they can do it. The important role of parents can be utilized in studies using family-based strategies. The Special Turku Coronary Risk-factor Intervention Project (STRIP [5Sääkslahti, et al. Effects of a three-year intervention on children's physical activity from 4 to 7 Pediatr Ex Sci 2004 ;  16 : 167-180

Cliquez ici pour aller à la section Références]) and the InPact intervention project [6Finni, et al. A family-based tailored counselling to increase non-exercise physical activity in adults with a sedentary job and physical activity in their young children: design and methods of a year-long randomized controlled trial BMC Public Health 2011 ;  11 : 944 [cross-ref]

Cliquez ici pour aller à la section Références] were initiatives based on social learning theories. The goal was to try to increase children's PA through their parents. These projects provided parents with knowledge (explaining why PA is needed, what it is and how it can be implemented) and encouragement by introducing concrete actions and ideas (through articles, posters, radio and TV programs, Internet video clips and demonstrations). STRIP focused on individuals but was realized through group activities. In the InPact, the implementation was fully individualized. A considerable amount of children spend most of their time in childcare, so PA interventions designed for childcare seem to be needed. The Early Steps [7Iivonen, et al. The development of fundamental motor skills of four- to five-year-old preschool children and the effects of a preschool physical education curriculum Early Child Dev Care 2011 ;  181 : 335-343 [cross-ref]

Cliquez ici pour aller à la section Références] intervention project focused on developing child care curriculum and teachers’ in-service training. On the other hand, the ongoing Home- and childcare -based Intervention to Promote Physical Activity (HIPPA) intervention tries to commit both childcare and the family to share the educational responsibilities of children [8Mehtälä, et al. The effect of the HIPPA-intervention on childcare and home physical activity  :  (2014). [Submitted].

Cliquez ici pour aller à la section Références].

Practical experiences are important. Together with systematic analysis of previous intervention studies, we can find the most effective intervention strategies. Some systematic reviews have been made to find the most effective elements in PA interventions. In their economic analysis, Wu et al. [9Wu, et al. Economic analysis of physical activity interventions Am J Prevent Med 2011 ;  40 : 149-158 [cross-ref]

Cliquez ici pour aller à la section Références] concluded that PA interventions executed in different institutions, such as in childcare, were the most cost-effective interventions. Gordon et al. [10Gordon, et al. Effectiveness of physical activity interventions for preschoolers: a meta-analysis Res Quart Ex Sport 2013 ;  84 : 287-294 [cross-ref]

Cliquez ici pour aller à la section Références] found that the amount of moderate-to-vigorous PA increased most under the following conditions: (a) when the intervention is implemented in a community- or institutional-based design), (b) when the duration was four weeks or less, (c) when the project was organized within childcare, (d) when it was teacher-led, (e) when it focused on increasing time for outdoor play, and (f) when it incorporated unstructured activity. Mehtälä et al. [11Mehtälä, et al. A Socio-ecological approach to physical activity interventions in childcare: a systematic review Int J Behav Nutr Phy Activity 2014 ;  11 : 22

Cliquez ici pour aller à la section Références] analyzed PA intervention projects from a socio-cultural point of view. This analysis revealed that successful intervention projects tried to affect a PA-friendly atmosphere within the whole society. It also underlined the importance of combining the influence of the childcare and home environments. When parents and child care personnel have a common objective, the increase was most pervasive. Researchers do not always know what might be the critical keys to overcome the barriers in order to increase children's PA. That's why the experience of permanent childcare staff needs to be listened to carefully elaborate the intervention and select the most suitable solutions found together. Ward et al. [12Ward, et al. Interventions for increasing physical activity at child care Med Sci Sports Ex 2010 ;  42 : 526-534 [cross-ref]

Cliquez ici pour aller à la section Références], Iivonen and Sääkslahti [13Iivonen, et al. Preschool children's fundamental motor skills: a review of significant determinants Early Child Develop Care 2013 ;  184 : 7

Cliquez ici pour aller à la section Références] and the previously mentioned systematic analysis highlighted the curriculum's role in structured PA and in the development of motor skill. Teacher training has been shown to be an effective strategy for increasing teachers’ skills in PA promotion. Ward et al. [12Ward, et al. Interventions for increasing physical activity at child care Med Sci Sports Ex 2010 ;  42 : 526-534 [cross-ref]

Cliquez ici pour aller à la section Références] found that children's successful structured PA sessions lasted less than 45minutes and were implemented three times or less per week. They also raise an important question regarding what is the appropriate balance between structured and unstructured activity. It appears that too many activities with too much structure may result in losing the primary benefits of children's PA play: enjoyment, fun, spontaneity, freedom and flow experiences.

Based on practical experiences and systematic reviews, it can be concluded that positive associations between children's play and PA confirm that physically active play, both indoors and outdoors, is children's own and natural way to sustain their overall development. The amount of outdoor play is characteristic for children's physical activity. Thus, successful PA interventions should be based on creating PA-friendly circumstances for children's play. In practice, this approach means creating a physical environment that encourages children's PA play and that helps children to achieve their individual zone of proximal motor, cognitive and social development. Moreover, adults’ role is to offer space, give time, and allow freedom to try as well as to support PA play physically, mentally, and socially.

In order to implement projects aiming to increase children's PA, one should keep in mind that the PA of young children has been shown to increase when: (1) there is a lot of physically active play (e.g., possibilities for free playing, a high amount of outdoor playing on a daily basis and PA equipment is available during free play activities, (2) different learning and playing environments are used in multiple ways (e.g. forests, parks, the «Bullerby» model, paved areas), (3) staff members encourage children and use different outdoor equipment and toys together with the children (e.g., climbing bars, tire-swings, playground paintings, large toys that have to be pulled and pushed with one's whole body).