Physical Activity Levels for Preschool Children

Seven cross-sectional studies from between 2006 and 2016 were found that analysed the PA levels of preschool children. They examined Portuguese¹⁰, Danish¹¹, Canadian¹², Brazilian^13,14 and American children^15,16. The subjects’ age group from two to six years; the smallest group had 65 preschool children and the largest had 631.

Of the 7 studies, five used accelerometers Actigraph GT3X or GTM1: two only accelerometer^10,16; one accelerometer and observation in the institutional context¹¹; one accelerometer and routine observation¹⁵; and one accelerometer and questionnaire in school¹⁴, as the literature attributed greater precision and objectivity, and the others two studies used questionnaire: one validated questionnaire and adapted to Brazil¹³ and one semi qualitative questionnaire to parents¹².

Meantime this instrument (accelerometers) does not provide additional information of environment frequented by children¹⁷ and also need to unify measures of the level of PA performed by accelerometer¹⁸, because dependent on the interpretation of accelerometry data.

Different cut-off points to indicate the desired level of PA practice were used, as various countries have different official recommendations. The first guide containing PA practice recommendations for preschool children was proposed in the United States, by the National Association for Sport and Physical Education¹⁹. It recommended at least 60 minutes of moderate and vigorous PA daily (at least 3 day/week). The second edition of this guide suggested that preschool children (age three to five) should engage in at least 120 minutes of total PA per day, including 60 minutes of structured activities (planned with professional guidance) and another 60 minutes of unstructured activities²⁰.

Other recommendations published in Australia²¹, the United Kingdom²² and Canada²³ called for at least 180 minutes of daily PA for preschool children. Thus, there is no consensus on this issue. Brazil and Denmark did not indicate having any guidelines or official recommendations regarding PA for preschool children.

Using the original NASPE guidelines (which called for a minimum of 60 minutes of daily exercise), four studies found low levels of PA in 25% to 87% of the total participants, and sedentary behaviour in 50% to 83% of them. For instance, Tucker²⁴ investigated 39 studies from seven countries (United States, Scotland, Finland, Australia, Chile, Estonia and Belgium) and determined that across all these studies, 46% of preschool children showed low levels of PA, considering the recommendation of 60 minutes daily.

Three studies adopted the Canadian recommendations (180 minutes of daily PA) and found low levels of activity in 62% to 90% of all participants, while the incidence of sedentary behaviour varied from 64% to 90%. Chart 1 illustrates the findings of these studies.

Since three countries prescribe a daily minimum of 180 minutes of PA for preschool children (the Australia²¹, United Kingdom²² and Canada²³), whereas the American recommendations have had cut-off points of 60 or 120 min/day (NASPE^19,20), the choice between classification systems affects the number of children characterised as having insufficient PA. This inconsistency concerning the desirable minimum amount of PA was highlighted by Timmons et al.²⁵ and hinders comparisons among PA levels found in the studies. Moreover, all four countries’ (United States, England, Canada and Australian) recommendation of PA was derived from studies of adult populations and was adjusted for children under age five based on empirical observations. Although these actions are justified in view of the evidence of a relationship between lack of PA and increased health risks in early childhood, a more focused review is still desirable to establish consistent guidelines, identify suitable health goals and assess worldwide levels of inactivity among preschool children, as well as to clarify observations across different countries.

Despite this analytical difficulty, the results of the present review indicate that sedentary behaviour is increasing and that PA levels of preschoolers are often lower than those prescribed even by the US recommendations. Considering the NASPE criterion of 60 min/day of PA, the average percentage of children with low levels of PA across two review studies^24,26 varied in 34% a 94% and in this study it is 86% (sum of all mean of each study). This confirms that the risk of sedentary behaviour has increased in the period between 2006 and 2016. Of course, if one uses the stronger NASPE criterion of 120 min/day or the other three countries’ recommendation of 180 min/day, the percentage of insufficiently active children is even higher.

This situation is dangerous from a public health perspective because low levels of PA may enhance the risk of developing diseases associated with sedentary behaviour, such as obesity and cardiovascular diseases⁵, as well as other developmental risks^8,25.

Timmons et al.²⁵. and Ginsburg²⁷ have disagreed with the idea of defining an exact period of time for which all preschool children should perform PA, arguing that it should be a natural and meaningful action for all children, everywhere and at all times^25,27. However, systematic observations of the daily life activities of preschool children have shown that children often do not receive adequate opportunities to experience PA as a meaningful and natural action²⁸.

Therefore, it is important to establish reliable and efficient guidance that considers the various characteristics of preschoolers and analyses other factors that may be associated with low PA levels in preschool children. Additionally, it is important to review how PA programmes have been implemented for such children during the period between 2006 and 2016.

Implementation of Physical Activity Programmes for Preschool Children in the Period between 2006-2016

Among the studies of PA programmes in actual practice in the period between 2006 and 2016, this review focused on ones that examined children from the US^29,30, Germany^31,32, England³³, Belgium³⁴ and Canada³⁵. The age of children studied ranged from three to six years old and the sample size of children varied from 50 to 826 participants. The period of the intervention programmes ranged between six weeks and two years.

The instruments for data collection were: Accelerometer ActiGraph GT3X²⁹; accelerometer (model not specified) and anthropometric measurements³¹; accelerometer ActiGraph GT1M and structured questionnaire to parents³³; ToyBox-intervention (six steps)³⁴; accelerometer (model not specified), motor test and anthropometric measurements and semi qualitative questionnaire to parents³²; accelerometer (model not specified) and instruction to teacher’s³⁰; accelerometry (model not specified), body composition and instruction to teacher’s³⁵.

All studies implemented daily PA, except De Bock et al.³¹ in which PA took place twice a week. The amount of PA time provided varied among 30, 35, 60, 120 and 180 minutes per day; De Bock et al.³¹ did not clarify this information.

An increase in PA levels was demonstrated in five studies; Goldfield et al.³⁵ and O’Dwyer et al.³³ documented the best results. They offered, respectively, 60 min/day and 180 min/day of activity, complying with the American²⁰ and United Kingdom²² determinations. Although the results were positive, in three studies, the estimated time of the daily activity did not reach the minimum PA time recommended for preschool children. De Craemer et al.³⁴, was the only one study that did not obtain positive results. Study findings are shown in Chart 2.

The ages correspond to the age group proposed in preschool children, therefore it is in agreement with the expected parameters, and the PA was offered with different frequency, duration, intensity and quantity. The methods of determining the level of PA also varied. De Craemer et al.³⁴, Goldfield et al.³⁵ and Pate et al.³⁰ classified three intensity levels of PA, whereas Annesi et al.²⁹, Bock et al.³¹, O’Dwyer et al.³³ and Roth et al.³² analysed only one or two distinct levels.

As a result of these differences, appropriate comparisons among the studies cited are difficult, corroborating the conclusion by Timmons et al.²⁵ that there is no consensus as to the amount, type, frequency or intensity of PA proposed for preschool children.

However, a meta-analysis of Gordon et al.³⁶ on the effects of PA programmes for preschoolers determined that strategies with at least four weeks of intervention achieved positive results in raising moderate levels of PA in children. These interventions primarily involved changes in the environment and the introduction of outdoor activities³⁶.

Factors Associated with Physical Activity Practice in Preschool Children

Factors associated with PA levels among preschool children were analysed in 14 studies, nine of which referred to the factors of physical environment and socio-economic characteristics (Barros et al.¹³, Barbosa et al.¹⁴, Henderson et al.¹⁵, Tandon et al.¹⁶, Faria et al.²⁸, Bürgi et al.³⁷, Dawson-Hahn et al.³⁸, Olesen et al.³⁹, Vale et al.⁴⁰). Three studies referred specifically to parental or family factors (Loprinzi and Trost⁴¹, O’Dwyer et al.⁴², Remmers et al.⁴³). The other two examined issues of professional preparation (Androutsos et al.⁴⁴, Howie et al.⁴⁵).

Among the 14 studies, ten used questionnaires (validated questionnaire and adapted to Brazil¹³; structured form of daily preschool analysis^14,28,43; parental characteristics questionnaire^37,38,40; semi qualitative questionnaire³⁹; international physical activity questionnaire - IPAQ^41,42) and nine used accelerometers (ActiGraph GT1M^{15,37,38,40,42}; ActiGraph GT3X^14,16; ActiGraph GT1M and GT3X³⁹; ActiGraph 7164⁴¹) to associate environmental factors with PA levels and sedentary behaviour; to identify the activities performed by children and discussed capacity strategies and the participation of parents and teachers. Chart 3 presents relevant details on these studies.

The studies identified the following as positive factors that contributed towards increasing or preserving children’s level of PA: (a) recreational time; (b) time for outdoor activities; (c) physical space for games and recreation; (d) use of parks; and (e) indoor space for adapted games. Negative aspects included (a) rigid school routines; (b) overuse of academic activities that leave children in queues, sitting and waiting; (c) time spent playing with toys; (d) lack of space at home; (e) full-day school attendance; and (f) time spent watching television.

The availability of open space and a suitable environment is clearly essential to raise the level of PA among preschool children in educational or child-care settings, at home and in public areas^15,16,43. Another favourable step is to reserve dedicated time in school or elsewhere for children to move around^14,28.

Children’s sedentary behaviour has been linked with the amount of time spent watching television³⁸, the absence of space for physical activities¹³, inflexibility in the school routine and a heavy emphasis on academic activities that require children to stay seated for long periods of time²⁸. This last practice is contrary to official recommendations, which discourage engaging children in sedentary activities for more than 60 minutes at a time^20-23.

In studies related to professional factors, the following were associated with increasing or preserving PA levels: (a) suggestions and training models, capacity and professional qualification between universities and schools; (b) the teacher’s actual participation in and encouraging children to engage in physical activities; and (c) planning and the choice of activities^44,45.

Although the literature has still not proven a direct relationship between training programmes for teachers and increased PA levels for preschool children, the case study conducted by Howie et al.⁴⁵ observed two teachers during three years of training, which enabled them to increase the PA opportunities offered to children.

Teachers’ professional development and behaviour can influence the healthy habits of preschoolers, especially with regard to their practice of PA; this finding was reported by Ward et al.⁴⁶, in a review of studies on the daily behaviours adopted by teachers that contributed towards children’s healthy development.

In the studies related to family factors, those associated with increasing or maintaining high levels of PA included (a) parents’ involvement and participation; (b) guidance booklets, information and instructions offered to parents; and (c) the availability of extracurricular activities^13,41-43. Factors shown to have a negative impact were (a) inadequate parental health habits or obesity^37,38 and (b) higher level of parental education⁴⁰.

Loprinzi and Trost⁴¹ demonstrated promising results in terms of increased PA among children when the parents became participants in activities and projects developed by children in their school. Similarly, both O’Dwyer et al.⁴² and Remmers et al.⁴³ showed how parents’ healthy life habits influence the behaviour and habits of children, both within and outside school, which contributes to the review of Brown et al.⁴⁷ about of the involvement of the family to increase physical activity in children.

Barros et al.¹³ and Vale et al.⁴⁰ found an association between lower levels of child PA and higher levels of parental education, but Bürgi et al.³⁷ and Dawson-Hahn et al.³⁸ reported opposite results (higher level of parental education higher level of PA). Therefore, the interaction between the socio-cultural context and levels of PA should be further investigated.

The negative factors associated with PA levels of preschool children suggest the need for modifications of the institutional environment, not only in the structural and physical sense but also to provide better incentives and opportunities for children to develop, researches that use ecological models is necessary⁴⁸.

The context in which the child is inserted must respect his or her individual characteristics, such as whether the child enjoys running. It should also encourage social relationships and diverse experiences in environments frequented by other children, both at school and elsewhere. The insertion of active play, as noted by Ginsburg²⁷, has been identified as a positive factor in encouraging PA among small children.

Limitations and Recommendations for Future Research

The points of uncertainty and disagreement that exist between official recommendations and between the methods used to detect and to improve PA levels do not seem to have benefitted scientific research in this area. They may also have held back efforts to devise strategies to combat sedentary lifestyles and increase PA among preschool children. Therefore, further discussion of these topics should take place.

The influence of parental education on children’s PA remains to be clarified, as the results of existing studies were contradictory on this point; high levels of parent education were associated with high PA among preschool children in two studies and low PA in two others.

Although there is no consensus on what amount of time spent in a sitting position constitutes sedentary behaviour in children, there is evidence that the percentage of preschool children with inadequate PA time has increased in recent years. This lack of PA could damage their development as well as increasing their risk of various diseases. And contextual variables (family environment, school environment, the child and activities performed) have too that influence the PA levels of children. Consequently, an increase in PA among preschoolers is urgently required, and public policy should encourage this change.

To construct efficient policies and to design actions that will lead to increased PA, it is essential to better understand how preschool children experience different aspects of PA. Therefore, more research should be conducted on contextual variables related to PA among preschoolers.