School-Based Physical Activity Interventions in Children and Adolescents: A Systematic Review

Background: The aim of this systematic review was to examinemotivational interventions based on physical activity as precursor of psychosocial benefits inside of the scholar context. Method: studies were identified in seven databases (Web of Science, Sport Discuss, Scopus, Eric, Pubmed, Psycinfo and Google Scholar). The search process was from June 2011 to September 2019. A total of 41 articles met the inclusion criteria. Results: 23 studies showed psychological effects after intervention and also 10 studies showed psychosocial effect after the intervention. The rest of the studies, although they presented changes, did not become significant. Conclusions: this systematic review showed the importance of motivational processes for the performance of physical activity and sport as a precursor of psychosocial changesand highlights the importance of strategies and the temporal nature of studies to maintain significant changes over time.Likewise, the study shows the future trend of motivational interventions, highlighting the female gender as participants of special interest, and changing the methodology through web-based interventions and active breaks or mental breaks during traditional subject classes.


Introduction
The period of childhood and adolescence is a key period in the acquisition of healthy habits, since insufficient levels of physical activity (PA), during any stage of growth, can contribute greatly in the promotion of overweight and obesity [1]. In this regard, PA is understood as any body movement produced by the contraction of skeletal muscle and substantially increases energy expenditure [2]. However, there is strong evidence of the importance of PA in children and adolescents' physical and psychological development, promoting an increase in mental acuity, acquisition of mental skills, and the adoption of more active and healthy behaviors, which help them face challenges related to higher life expectancy [3], such as those associated with low PA and increased sedentary behaviors [4].
Moreover, it is also important to emphasize some of the benefits of PAon physical, psychological, and social health. In this regard, the benefits of PA on health include the improvement of basic physical skills, physiology, morphology, body mass index, and reducing the percentage of fat [5], which is closely related to cardiovascular diseases. Also, at the psychological level, it has been associated with an increase of self-esteem [6], decrease in stress [7], emotional processes [8], cognitive achievement [9], and social behavior [10].
Hence, the volume of theoretical research on the benefits of PA currently tends to increase. Despite this increase in scientific literature [11][12][13], there are few investigations with a quasi-experimental design compared to cross-sectional designs. There are even fewer that refer to the psychosocial benefits compared to those referring to physical benefits. In this sense, the intervention process is characterized by the manipulation of independent variables over time, which provides more information about the results of intentional manipulation to improve educational outcomes. From a theoretical perspective, intervention studies help to better comprehend the causal relationships between psychological variables (i.e., motivation) and those of the educational environment [14,15], because intervention implies putting the theory into practice within the educational context. Similarly, from a practical perspective, intervention studies improve our understanding of interventions and their educational outcomes [16].
This work focuses on the role of motivation towards the intention to be physically active, adherence to the practice of PA, and the psychosocial consequences of such activity due to a healthy lifestyle, understanding as psychosocial processes those that are connected with human behavior (behavioral, attitudinal and self) in their social aspects, and that are developed over time through their interactions and experiences that allow their individual development. In this sense, motivation is an active process that encourages individuals to direct their attention and persistence towards the achievement of their goals [17]. This work has focused on two of the motivational theories that have been used most frequently in the educational context: Self-Determination Theory [18], and Achievement Goal Theory [19,20].
Self-Determination Theory [18] is the theoretical framework from which most research in this field was developed, and it has been widely used for the development of intervention strategies to improve student motivation during PA practice [21][22][23]. Furthermore, it is a macro-theory of personality and motivation, which proposes that context can influence the reasons for performing certain activities. It also focuses on the extent to which behaviors are voluntary or self-determined, maintaining that motivation is a continuum of self-determination, differentiating autonomous motivation (intrinsic, integrated, and identified regulation), controlled motivation (introjected and external regulation) and amotivation [18]. Intrinsic regulation constitutes the highest level of motivation, in which the performance of the activity in itself constitutes the objective and the gratification, producing feelings of competence and self-realization. Integrated regulation occurs when goals or regulations are fully assimilated with the self, and they are included in the individual's self-evaluations and beliefs about personal needs. Identified regulation refers to engagement in an activity because of one's positive assessment of it. Within controlled motivation is introjected regulation, associated with the performance of an activity to avoid feelings of guilt and to improve personal ego and/or pride [24]. External regulation refers to the performance of an activity to obtain an external reward or to avoid punishment. Finally, amotivation represents the absence of either intrinsic or extrinsic motivation [24].
According to this theory, the type of motivation shown by Individuals depends on the satisfaction of their basic psychological needs (BPN): competence, autonomy and relatedness. The satisfaction of these BPN or its lack will influence the well-being [25]. The need for competence is defined as the feeling of effectiveness while engaging in an optimally challenging task. The need for autonomy is characterized by the sense of initiative felt by the subjects when voluntarily participating in the proposed activities and, finally, the need for relatedness is defined by the individual's feeling of integration and acceptance in the context in which he or she interacts, in this case, with other classmates, developing positive social relationships in the school context [18]. In relation to the psychosocial benefits that derive from the satisfaction of the basic psychological needs, Prentice et al. [26] suggested that they are the best defined trends to look for certain basic types of psychosocial experiences, to a somewhat variable extent between individuals, and to feel good and prosper when those basic experiences are obtained, to the same extent between individuals.
On another hand, the Achievement Goal Theory [19,20] considers that people are directed by the goals they hope to achieve and that they act rationally in accordance with these goals [27]. In this sense, the success or failure an action depends on the individual's interpretation. Thus, what some people interpret as success is interpreted by others as failure [28]. According to this theory, achievement goals orientations refer to the cognitive representations through which students are involved in certain tasks [29]. In this line, in achievement contexts, there are two predominant types of involvement: ego-involvement, in which success is perceived when one's performance is better than that of others; and mastery-involvement, in which the term goal implies the improvement of one's personal competence. Therefore, the type of participation that a subject plays for a given activity will be the result of the motivational climate and the goal orientations presented by that individual [30].
Based on the above, this review aims to provide a broader view of the interventions carried out in schoolchildren, focusing not only on the benefits obtained in physical health through the promotion of PA as indicated by previous systematic reviews [31][32][33], but rather encompassing variables of a more psychosocial nature such as motivational processes, self-esteem, body image, sedentary lifestyle, quality of life, etc. This systematic review aims to answer the following questions: What incidences have the interventions based on the Self-Determination Theory or the Achievement Goal Theory on the curricular or extracurricular school context? Do PA levels increase? Do these interventions modify participants' psychosocial behaviors such as self-esteem or body image? What is the recommended duration for the development of an intervention program? Thus, the objective of this review is to test the presence of interventions develoed in the school environment framed in the Self-Determination Theory and Achievement Goal Theory through PA or physical education have caused changes in the psychosocial aspects of children and adolescents.

Materials and Methods
This study was designed following the structure and recommendation of other systematic reviews [34,35] and the treatment used by the PRISMA guidelines for reports and studies [36].

Search Limits
An exhaustive search was made within the following seven databases (Web of Science, SPORTDiscuss, Scopus, Eric, PubMed (via MEDLINE), PsycINFO and Google Scholar) from June 2011 to September 2019. Moreover, this date was decided due to the existence of the last article that, according to the selection criteria, maintained a close relationship with the purposes [37]. The databases were chosen based on the articles published in journals with an impact factor in Journal Citation Reports (JCR). The search strategies used were developed through the combination of the following keywords for each database: (Motivation OR Intrinsic Motivation) AND (Intervention OR Programme) AND (Physical Activity OR Physical Education) AND (Children) AND (Teenegers OR Adolescents) AND (School).

Selection Criteria
The components of the PICOS questions were taken into account, which refer to the Population, Intervention, Comparison and Results that were answered with the aim to define the eligibility criteria shown in Table 1. Table 1. Study selection criteria.

PICOS Eligibility Criteria
Population Children and adolescents between six and eighteen years old Intervention Intervention studies based on motivation for the promotion of physical activity and psychosocial benefits

Comparison
Compare an intervention group based on motivational principles that promotes physical activity through different strategies with a control group Outcome Any physical or psychosocial outcome is measured or reported.Psychosocial outcomes: individual's social and psychological aspects including, but not limited to cognitions, emotions, and mental health The search results were exported via e-mail to eliminate duplicates. The titles and abstracts were analyzed by two researchers independently. If there was any discrepancy, a third investigator was called to reach a consensus. Subsequently, the reference list of selected studies was reviwed to identify additional studies. The full texts of these articles were recovered. If their recovery in the databases was not possible, the author was contacted to request the full text of the research article, as it could still be in the process of being published (Figure 1). The inclusion criteria for this study were: (1) population: school children and adolescents, age 6-18 years; (2) theoretical framework: Self-Determination Theory or Achievement Goal Theory; (3) type of study: intervention study with control group and experimental group; (4) methodology: use of PA in the intervention program;(5) main outcomes: psychosocial effects of the intervention.
The exclusion criteria were (1) population: preschoolers, adults and older people; (2) theoretical framework: Theory of Planned Behaviour, Expectancy Value Theory, and Theory of Self-efficacy; (3) type of study: cross-sectional studies, systematic reviews and meta-analyses; (4) main outcomes: studies that only show changes in biological and health indicators.
The documents included were those from important journals, which were subject to peer review. The study included articles written in English with a population of 6-18 years of age. In addition, only those that presented a longitudinal intervention or intervention design were included. Likewise, the studies carried out within the educational context were selected.

Data Extraction and Reliability
The content analysis was carried out in order to analyze all the information present in the articles included in this review and in relation to the previously raised research questions. Therefore, the following categories were taken into account: author/s, sample (number, age and gender), objective of the study, intervention structure, duration and frequency of the program, assessed variables, main outcomes, and conclusions.

Evaluation of the Quality and Level of Evidence
The criteria for assessing the quality of the studies included in the review were taken from another standardized evaluation list [38], and our selection criteria. The list was composed of three items (ABC), where criterion A refers to the subjects participating in the study, B refers to the sociodemographic characteristics and the variables that are assessed in the studies, and finally the quality criterion C, is based on the complexity of the statistical analysis used. Each item was rated with a 2 (if it fully met the criteria), 1 (if it met the minimum standards) or 0 (if it did not meet the minimum standards). For all studies, the total quality was calculated by counting the number of positive elements (a total between 0 and 6). The studies were defined as high quality (HQ) if they had a score of 5 to 6. A score of 3-4 determined a medium quality (MQ), and finally, a score of 0-2 represented low quality (LQ). In addition, it was decided to complement the above criteria with the assessment of whether the intervention has followed a randomized design and the reliable in its implementation.

Overview of Studies
The total number of participants included in the present review was 14,523 participants, of which 2059 were school children between 6 and 11 years old [39] and 12,464 were adolescents between the ages of 12 and 17 years [40]. Also, a total of 245 teachers were responsible for carrying out the relevant interventions. The studies were conducted in Spain (n = 13), Australia (n = 8), United States (n = 5), Finland and England (n = 3), Canada and Italy (n = 2), South Korea (n = 2) Norway, Poland, Portugal, Estonia, Malaysia and Thailand (n = 1). Table 2 provides an overview of each of the 33 articles that contributed the data of this review.  Note: Range for the total score: high quality (HQ); medium quality (MQ); low quality (LQ). Parameter A: number of participants: 0 = less than 10; 1 = from 10 to 50 participants; 2 = more than 50 participants.Parameter B: description of the population and variables: 0 = fewer items than those required for value 1; 1 = sex, age, health status, and physical level; 2 = more items than those required for value 1. Parameter C: statistical analyses included in the study: 0 = such analyses not included in the value 1; 1 = error indexes or regression analysis; 2 = at least 3 graphical elements or repeated measures ANOVA. Parameter D: is the studie randomized? Parameter E: fidelity in the implementation.

Educational Level Uses
The most frequent grade levels for the performance of interventions based on the Self-Determination Theory and the Achievement Goal Theory in PA is Secondary Education (11-17 years), with 40/45, and to a lesser extent in Primary Education (6-11 years), with 5/45.

Design of the Programs
Most of the interventions in this review 39/45 presented a quasi-experimental design (2 × 2), a control group (CG), and an experimental group (GE) with two collection measures, one at the beginning of the program and another at the end of it [39,76]. Other investigations presented works of a different nature 6/45, where the same group was assessed at the beginning, and another one at the end of the intervention program [46,65,78]. Likewise, intervention processes with quasi-experimental design, a CG and an EG were also found, and three data collection moments 5/45 [47,62,63]. In this regard, researches were also found with four data collection moments 2/45 [22,54,68]. Finally, we might highlight a study where data was collected from the experimental group at three different times (i.e, at the beginning of the program, in the midle, and the follow up measure), and the control group only the initial measure and the follow up [42] (Table 3). The present trial was ineffective in its primary aim of reducing recreational screen-time. Significant intervention effects were observed for participants" autonomous motivation to limit screen-time, which mediated changes in screen-time We conducted three 2-h seminars with teachers before the data collection and intervention, as well as three meetings during the treatment that lasted approximately 40 min each. Each teacher was responsible for a "group involved in the task" and a "group committed to the ego" The design was 2 × 2 2 groups during two times and the intervention was for 6 weeks, twice a week         The results indicated the importance of creating a task-oriented climate in PE classes that will promote the most positive experiences

Outcomes
Three research questions were asked from the 45 studies: • What incidence do interventions based on Self-Determination Theory or Achievement Goal Theory have in the curricular or extracurricular school context? • Do PA levels increase? Do the participants' psychosocial behaviors modify their self-perception, body image, levels of motivation, quality of life, fun, boredom, and the psychosocial climate? • What is the recommended duration for the development of an intervention program?

Focus of Studies and Context
All the studies of the review presented the application of a PA program in the school environment based on two of the most used theoretical models in the study of motivation: Self-Determination Theory [24]; and Achievement Goal Theory [19,20]. In this sense, a large number of investigations of this review were based on the postulates of the Self-Determination Theory 42/45, of which 8 of them were based on both theoretical frameworks (Self-Determination Theory and Achievement Goal Theory), and 11/45 of the total of works were based on the Achievement Goal Theory. Only one study was completely based on the Achievement Goal Theory [45]. In two of the studies based on the Self-Determination Theory [51,59], the Cognitive Social Theory [81] was also used to assess perceived competence. Table 4 shows in more detail the results obtained in the different interventions that are part of this systematic review for each variable, showing the results for the different conditions of the participants (control and experimental). In this sense, the present review shows changes in the levels of motivation in 45/45 of the selected articles. In view of the totality of concepts that included in the two theories, it would be necessary to specify in which dimensions these changes take place. In this line, 14/45 (31.1%) of the studies showed changes in autonomous motivation [67,68,78] but not in all case these changes have been positive or significant [52,73]. In this regard, the motivational construct has not always been directed for PA [74], but also toward caloric intake [52], and screen time [77]. Similarly, other studies 14/45 (31.1%) of these investigations had positive effects on intrinsic motivation [39,42,64,75], 14/45 revealed effects on identified regulation (31.1%) [39,42,48,64,76], and 2/45 (4.4%) of the investigations showed effects on integrated regulation [54,61].
In relation to the effects produced in the BPN, 21/45 (46.6%) of the investigations showed effects after the application of the interventions. In this line, we should differentiate these effects according to the nature of the type of BPN (satisfaction, frustration and support). 13/45 (28.8%) of the studies showed effects on BPN satisfaction [50,76], 7/45 (15.5) effects on BPN thwarting [22,47], and 14/45 (31.1%) support on BPN [73,77], showing an increase in the satisfaction of autonomy in the experimental group. Likewise, the studies by Amado et al., Bechter et al. [42,44], and Cheon et al. [47] revealed an improvement in autonomy, competence and relatedness after the intervention. Other studies [74,76] showed positive effects of the interventions on the variables of satisfaction of autonomy and competence. Abos et al. [41] AndGonzález-Cutre et al. [54] reported a significant improvement in the experimental group in satisfaction of the three BPN. On another hand, studies revealed effects related to the thwarting of BPN. In this sense, the intervention of Cuevas et al. [48] increased BPN thwarting, whereas other investigations reported a decrease in those scores [22,47].
Regarding the effects in the studies based on the Achievement Goal Theory, 6/45 (13.3%), in all of them, there was an increase in mastery involvementtask-oriented climate [41,60,72,76], and in 6/45 (13.3%), there was a decrease in ego orientation [45,55]. On the other hand, there was an intervention that had no effect between pre and post, and also showed a reduction in the task-oriented climate and an increase in the ego-oriented climate [56].
On another hand, 6/45 studies (13.3%) included physiological and anthropometric variables such as adiposity, body mass index, and cardiorespiratory fitness. In this line, regarding the body mass index, some studies of the present review showed that, although it was reduced in some of the cases [39,40,59,64,78], this decrease did not reach significance. No changes were revealed in the adiposity index [64]. Finally, there was a significant increase in cardiorespiratory fitness [40,63,77].

Outcome on Duration of the Program
The duration of the interventions ranged from four weeks [66] to two years [56,60], but most of the intervention programs had a duration that ranged between 5 and 20 weeks [40,64]. Likewise, the number of lessons was between eight sessions [76] and 24 sessions [43,50]. Similarly, the interventions with the greatest effect were those whose duration ranged between three months and one year 19/45 (42.2%) [78]. Moreover, as mentioned in the inclusion criteria, duration was not a determinant for the elimination of the article. In this sense, 19/45 (42.2%) of the interventions performed lasted less than three months and did not show significant effects [41,42,45,46,48,51,[66][67][68]73,76,77,79]. However, it is important to point out five of them, which obtained significant results [46,51,61,72,77]. This criterion, which evaluates the effect of the intervention according to its temporal nature, has been used in a review of a similar nature [82]. On another hand, 6/45 (13.3%) studies [55,56,60,62,63,69] presented a duration of more than one year, but the effects of intervention did not show changes in some of the collection moments.

Main Effect on the Intervention
The effect sizes for each variable of each of the interventions included in this systematic review are described below (see Table S1).
Not all articles in this review have effect sizes, in some cases they do not report such indormation, or the effects are not strong enough to be categorized as small. In addition, it should be taken into account that not all studies have the effect size with the same statistic (Cohen's d; η 2 ; η 2 p; Clif delta; R 2 ).
In relation to the effects on BPN we have to distinguish between satisfaction, support and twarting. With respect to the satisfaction, Amado et al. [21], Lonsdale et al. [62], How et al. [58], and Sánchez Oliva et al. [73] reported a small effect on autonomy satisfaction. Consistent with this result, Cheon [22,47] they showed, respectively, a positive effect of a moderate nature in the satisfaction and support of autonomy, and in the satisfaction of the threeBPN, while the frustrations of the 3 BPN are reduced.Similarly, Tilga et al. [80], showed changes in the satisfaction of the BPN while reducing the thwarting of the BPN of autonomy with small effects. Franco and Coteron [50] and Sevil et al. [76] reveal important effects on the satisfaction of autonomy and competence. Moreover, Bechter et al. [44] showed after his intervention moderate and small effects on autonomy, competence and relatedness, respectively. Laroche et al. [61]. Lonsdale et al. [62] and Perlman et al. [67] demonstrated, after their interventions, a small-moderate effect on the satisfaction of the BPN. Regarding the support of the BPN, García-Calvo et al. [23], González-Cutre et al. [53], González-Cutre et al. [54], Piipari et al. [68], Sevil et al. [75], Sevil et al. [76] and Shannon et al. [77], showed a moderate effect of their interventions. In this regard, Sánchez-oliva et al. [73] emphasized a small effect on autonomy support (η 2 p = 0.08) and relatedness (η 2 p = 0.05). Finally, respecting the thwarting of the BPN, Cuevas et al. [48] showed a reduction in the need for thwarting for the experimental group with an effect size (η 2 = 0.037) Regarding the effects shown according to motivational orientations, Kokkonen intervention works et al. [60] and Rokka et al. [71] showed small size effects (η 2 = 0.04) in the task-orientated climate. Similarly, Grasten et al. [55], and Sevil et al. [75] reported average effect sizes (R 2 = 0.37). Finally, Bortoli et al. [45], and Sevil et al. [76] obtained important size effects on the task-orientated motivation. (Cohen's d = 0.80). On the other hand, respecting the performance motivational climate, Grasten et al. [55], Kokkonen et al. [60], and Sevil et al. [76] reported after their interventions a small effect size (η 2 p = 0.036). In this sense, Bortoli et al. [45], Rokka et al. [71], and Sevil et al. [75], showed a reduction in ego-oriented scores with medium effect sizes (Cohen's d = 0.50).
Concerning the effects produced in the behaviors, most of the intervention studies had a small effect (Cliff's delta = 0.22) [50,73,76] in the intention to be physically active. In accordance to this, the study conducted by Cuevas et al. [48], and Rhodes et al. [70] presented an average effect size (η 2 = 0.015), and finally some medium important effect sizes were shown in Abos et al. [41], and González-Cutre [53] (Cliff's delta = 0.45). Regarding sedentary behavior most of the studies [47,48,62] showed a small-medium effect size (Cohen´s d = 0.13), and onlyLubans et al. [64] showed an important effect size (Cohen's d > 0.80). In relation to studies that improve the quality of life, Girelli et al. showed average effect sizes. Respecting the improvement in PA, most of the studies reported small-medium effect sizes [40,46,[54][55][56]58,62], only two studies showed important effects on physical activity [53,63]. With regard to the attitude, this is treated differently by various authors. On the one hand, in relation to the attitude as a general dimension, small average effect sizes were shown (Cliff delta = 0.34), in the cognitive attitude, [41,74] important size effects were shown, and in the attitude towards learning [49] and competition [57] médium size effects were shown. Finally, respecting the effort [44,72] a médium size effect was shown (Cohen's d = 0.30).
Regarding anthropometric variables and cardio-respiratory fitness, most intervention studies did not report effect sizes. In this regard, Lubans et al. [64] revealed an important size effect on cardiorespiratory fitness (Cohen's d = 5.9), andRiiser et al. [40] showed an important size effect on body mass index (Cohen's d = −0.70).
Regarding the effects on psychosocial variables, it should be noted that the intervention de Riiser et al. [40] showed effects medium effects on body image (Cohen's d = 0.56). Furthermore, respecting appearance, Hajar et al. [57] showed after their intervention a médium size effect. Moreover, regarding quality of life, Riiser et al. [40], and Shanon et al. [77] showed small and medium effect sizes respectively. In this sense, Babic et al. [43] showed a small effect size on well-being. Regarding the impact of interventions on fun and boredom, most studies [41,50,57,67,[74][75][76] showed medium-important effect sizes in the fun. On the other hand, the interventions of Cuevas et al. [48], and Sevil et al. [74] reduced boredom scores with average effect sizes. Respecting self-efficacy, the researches [44,46,76,80] showed a medium-sized effect after the application of the intervention. With regard to the psychological condition, the intervention of Hajar et al. [57] showed a small-medium impact on the effect size (η 2 = 0.09). Finally, in relation to the impact on prosocial and antisocial behavior, important studies [45,47,53,61,76] showed medium-important effect sizes regarding the promotion of prosocial behavior. In this line, the interventions conducted by Bortoli et al. [45], and Cheon et al. [47] showed a reduction in boredom with an average effect size.

Discussion
The objective of this article was to review intervention studies based on the application of Self-Determination Theory, Achievement Goal Theory, or both carried out in the educational context. For this purpose, only intervention programs that present evidence of methodological quality were included. The results and their implications have been ordered according to the previously presented research questions.
Thus, in relation to the first question, the findings showed that most of the intervention studies are based on the Self-Determination Theory [18]. This may be due to the amount of constructs concerning human behavior that are included. In this sense, Self-Determination Theory itself in its postulates emphasizes that many of the investigations based on this theory have assessed environmental, social and personal factors in order to assess their effect on the behavioral manifestations of the individuals [24]. In this regard, many of the intervention programs provide instructions to the teacher as a means of transmitting techniques that increase or decrease levels of motivation.On another hand, some of the interventions were developed from both motivational theories [60,63,76], the Achievement Goal Theory and the Self-Determination Theory. In this line, previous studies show that these two methodological approaches can complement each other to give a more complete view of motivation independently of an educational or sporting context.In this sense, Lazowsky andHulleman [16], showed in their review and meta-analysis that a large part of the interventions developed in the educational field used a multiple theoretical perspective (two or more different theories). Finally, this review revealed that only three of the interventions was based solely on the Achievement Goal Theory [19,20]. In this regard, Bortoli et al. [45] reported in their study that, after the application of the intervention program, a task-orientation was more strongly related to positive emotional states as opposed to ego-directed intervention. All articles presented greater or lesser effects on motivation, satisfaction and support of the needs of autonomy, competence, and relatedness through the application of techniques and strategies taught by teachers or researchers [42,54,73,77]. In this sense, this review showed that interventions carried out in the educational context have an important medium effect on the most autonomous forms of motivation [44,48]. This fact may be due to the fact that high scores are reflected in the most intrinsic forms of motivation, and that the inclusion of innovative elements as support through the Internet [40] or the use of exergames [70] can easily manipulate these types of motivation. Likewise, it was shown that the changes in motivation are mostly predicted by the support and satisfaction of the BPN [22,47,54], which showed moderate exchange effects. This may be due to the fact that in many of the interventions they base their strategies on the support of autonomy [58,74], relegating to a second level the basic psychological need for competence. In this regard, this review has shown that satisfaction or support directly affects the motivation generated (autonomous or controlled) [50,67,76] and the goal orientations [74].
The intervention programs presented in this review also revealed effects on fun, boredom, and usefulness for the improvement in levels of motivation and PA in the educational context. In this line, Franco and Coteron [50] pointed out that several studies agreed on the positive effects in supporting autonomy or other BPN. Likewise, Rokka et al. [72], in their intervention developed around the TARGET areas [19] and support for autonomy, reported an increase in motivation and fun [19]. Showed that ego-involvement motivation would have a greater effect on boredom. In accordance to this issue, Texeira et al. [37] demonstrated that the most autonomous forms of behavioral regulation and PA can be important in the context of promoting an active lifestyle through the choice of optimal challenges that promote compromise and enjoyment. Also, some of the studies showed effects on the improvement of body image, and quality of life. In this regard, quality of life improved in the studies of Quaresma et al. [69] and Riiser et al. [40], associated, on the one hand, with the support of parents and partner, and, on the other, with body mass index. Similarly, this review showed the behavioral and psychosocial effects derived from intervention programs, revealing in some cases improvements in the intention to be physically active [50], sedentary behavior [63], lifestyle [52], physical activity [51], attitude [68], and effort [44], and in others showing negative growth [73]. This fact may be due to the fidelity of the intervention where, due to the fact that most of the interventions that are developed, are carried out by teachers and non-researchers, the application of the strategies previously shown to the teacher is not applied in the intervention. In this sense, previous research used audio or video recording devices where this fidelity is ensured [54,62,63]. Regarding the effects on psychosocial variables, in some cases improvements in well-being were shown [43], self-efficacy [44,46], appearance [57], psychological condition [68], subjetive norms [55], psychosocial climate [70], and prosocial and antisocial behavior [47]. In this regard, the changes in the psychosocial variables could be due to the intervention procedure developed by the different researchers where the results can guide the theoretical developments and improvements, which then influence the subsequent research and practice in a significant way [83]. It is also important to point out the effects in PA after an intervention, as in many of the investigations, it was the means to improve the psychosocial variables [46,51,77].
Finally, in relation to the intervention time, the result showed that time is an essential variable for changes to occur. In this sense, the interventions with a duration of less than three months [41,66,73] presented fewer effects than those whose duration ranged from three months to a year [22,49,50,52,54,58]. However, there are exceptions where shorter interventions showed significant effects in most of their variables. This may be due to the methodology used or the professional who performed the intervention [46,51,77]. In this sense, Texeira et al. [37] highlighted the need for interventions greater than 3 months and adds that there are a limited number of interventions in the PA domain, and they are highly varied. Nevertheless, they concluded that autonomous motivation might change behaviors and maintain them over time. However, the work of Fu et al. [51] was based on the application for nine weeks of the Sport Play and Active Recreation for Kids program (SPARK) to increase PA in schoolage children. In this work, pedometers were used, which could favor the increase in PA through self-informed feedback. In this regard, Bronikowski et al. [46] also used pedometers (Garmin vivofit), on which participants had to register and upload data once a week. Shannon et al. [77] conducted an intervention based on healthy choices, which used techniques from the Self-Determination Theory along with resources that were sent to parents for their collaboration. Furthermore, interventions that lasted more than a year showed stagnation in the rating of their measures [22]. This fact may be explained by the teachers' difficulty to motivate, capture the students' attention, and maintain it over time. In this sense, an excessively short time does not produce effects, and an excessively long time (more than a year) can produce a decrease in the levels of motivation due to the absence of the element of novelty.

Conclusions
The results of this systematic review should be interpreted with caution due to the variety of effects analyzed and the methods used. Some of the weaknesses of the studies include a temporal limitation, which makes it difficult to obtain the effects of the intervention. In addition, some of the investigations did not include control guidelines to confirm which teachers and technicians applied the strategies and techniques previously taught by researchers. More intervention studies are required to expand on other motivational theories in order and to assess the effects on variables over time. An important limitation of the present review is that it did not include studies using a qualitative methodology. The absence of these studies precluded knowing testimonies transcribed from other interventions.
Future studies should be directed towards the complementation of the present systematic review with a meta-analysis that assesses the size of the effect of the interventions. In addition, future researchshould include mixed methodologies in their interventions and implement new strategies that will have a greater effect on the participants. In this sense, it is important to take advantage of new technologies to improve collaboration among teachers, families, and peers in order to carry out more effective interventions whose outcomes are maintained over time.
In conclusion, this review of the interventions carried out in the educational context provides a series of methodological recommendations when proposing and developing future intervention studies. In this sense, it is of utmost importance to highlight the strategies and the temporal nature of the studies that did maintain significant changes over time. Moreover, new future lines of research are also glimpsed. First of all, a new research trends in the female gender are put into focus as can be seen in the following research [71], which could lead to the significant decline of the female gender PA levels during adolescence. Secondly, it also highlights web-based interventions as a way to reinforce behavior. And finally, it is important to improve school PA with active breaks and brain breaks (mental breaks). Funding: This research was funded by the contribution of the Ministry of Economy and Infrastructure throught the European Regional Development Fund (ERDF), and European Social Fund Ang Government of Extremadura for JJP: PO17122.

Conflicts of Interest:
The authors declare no conflict of interest.