Pediatric Exercise Science, 2015, 27, 314 -333 http://dx.doi.org/10.1123/pes.2014-0148 © 2015 Human Kinetics, Inc.
REVIEWS
Interventions to Increase Physical Activity in Children Aged 2-5 Years: A Systematic Review Jiying Ling Michigan State University
Lorraine B. Robbins Michigan State University
Fujun Wen Michigan State University
Wei Peng Michigan State University Comprehensive evaluation of prior interventions designed to increase preschoolers’ physical activity is lacking. This systematic review aimed to examine the effect of interventions on objectively measured physical activity in children aged 2–5 years. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. In May 2014, we searched PubMed, CINAHL, PsycINFO, ERIC, SPORTDiscus, Cochrane, and Embase. Two reviewers independently identified and appraised the studies. Twenty-four articles describing 23 independent studies and 20 unique interventions met inclusion criteria. Of the 8 interventions resulting in a significant effect in objectively measured physical activity, all were center-based and included a structured physical activity component, 6 included multiple components, 5 integrated theories or models, and 4 actively involved parents. Seven of the 8 were randomized controlled trials. Due to the heterogeneity of the study designs, physical activity measures, and interventions, drawing definitive conclusions was difficult. Although the overall intervention effect was less than optimal, the review indicated that theory-driven, multicomponent interventions including a structured physical activity component and targeting both parents and their children may be a promising approach for increasing preschoolers’ physical activity and warrant continued investigation using rigorous designs to identify those that are most effective. Keywords: review, exercise, preschool, program evaluation From 1990 to 2010, the worldwide prevalence of overweight and obesity among preschool children has increased from 4.2% to 6.7%, and is expected to reach 9.1% by 2020 (20). In the U.S., 22.8% of children, aged 2–5 years, are overweight or obese (50). Children who are overweight at age 5 are 4 times as likely as those of the same age with a healthy weight to become obese in either later childhood or adolescence (17). These Ling and Robbins are with the College of Nursing, Wen, the Dept. of Kinesiology, and Peng the Dept. of Media and Information, Michigan State University, East Lansing, MI. Address author correspondence to Jiying Ling at jiying.ling@ hc.msu.edu.
314
alarming findings indicate that excess body weight early in a child’s life may be strongly correlated with subsequent obesity risks. Children who participate in a physical activity (PA) and nutrition intervention at an earlier age (< 5 years) have greater weight loss over 2 years than those who participate in the same intervention at an older age (> 5 years) (15). Therefore, intervening before the start of elementary school holds promise in reversing the current epidemic of childhood obesity. PA is protective against obesity during the preschool years (57) and is essential for children’s physical, cognitive, social, and emotional development at all ages (28). Children aged 3–5 years who are inactive are 3.8 times more likely to gain subcutaneous fat than
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those who are active (43). Preschoolers’ accelerometermeasured vigorous PA is significantly associated with their lower odds of being overweight (40). A recently conducted systematic review indicates that a high level of PA not only reduces adiposity, but also improves motor skill development and psychosocial and cardiovascular health in children aged 0–4 years (68). These studies support that important health benefits are accrued from PA. Although PA guidelines have been developed in several countries, the amount of daily PA recommended is inconsistent. Recommendations in Australia and the United Kingdom indicate that preschool children should participate in at least 3 hr of PA every day, including light, moderate, and vigorous PA (62). The U.S. National Association for Sport and Physical Education (NASPE) (45) guidelines call for 120 min of daily PA. Moreover, the U.S. Institute of Medicine (IOM) (35) recommends that preschool children should participate in 15 or more minutes of PA per hour, approximately 3 hr per day. Based on accelerometer data, preschool children actually participate in an average of 43 min of moderate to vigorous PA (MVPA) daily (13). Regardless of the guideline discrepancies, the majority of preschool children worldwide do not meet current PA recommendations (58,62,69). Conducting interventions during early childhood may be a promising approach for assisting children to establish a positive behavioral pattern that has the potential to continue into adulthood (66). Although many interventions have been conducted to increase PA in preschool children, current information on their overall impact, especially factors influencing the intervention effect, is lacking. Two systematic reviews only focus on PA interventions conducted in childcare center-based settings including daycare or childcare center, preschool, and nursery (39,70). One metaanalysis, including studies conducted before 2012, examined the effect of PA interventions in preschool children (30). Although childcare center-based settings provide an excellent location for PA interventions, examining interventions conducted at home or other community settings (e.g., church, park, outpatient clinic, or hospital) is also essential to acquire information for targeting children’s home and community environment. In all 3 reviews, PA was operationally defined and measured in a variety of ways including proxy reports. Due to the limited reliability and validity of proxy reports of PA (54), results of the 3 reviews may be questionable. Previous reviews focusing on identifying factors influencing the intervention effect have yielded somewhat contradictory findings. One review of 19 studies conducted in childcare center-based settings indicated that regular structured PA programs had a beneficial effect in increasing PA among preschoolers (70). In contrast, a meta-analysis of 15 studies showed
that short-term (< 4 weeks), teacher-led PA programs including outdoor activity and unstructured PA were most effective (30). Finally, another review that included 23 studies conducted in childcare center-based settings noted no effect of theory-based, multicomponent interventions (39). The inconsistent findings, possibly due to the heterogeneity of the included studies, limit the ability to draw conclusions regarding factors that influence the intervention effect. This paper adds to the existing body of knowledge by conducting a systematic review of all relevant PA intervention studies up to May 2014 that involve preschool-age children and include an objective measure of PA, such as pedometers and accelerometers. To efficiently inform future research efforts directed toward preventing obesity among older children and adolescents, effective and sustainable interventions and strategies targeting PA in preschool-age children need to be identified. Less biased than a narrative review, a systematic review can assist with achieving this objective by offering a rigorous and comprehensive examination of all studies addressing a specific topic (26), such as PA interventions among preschoolers.
Objective The aim was to examine the effect of interventions on objectively measured PA in children of preschool age. In this study, preschoolers represent children aged 2–5 years. Research questions were: (a) What types of interventions have been conducted to increase objectively measured PA in preschoolers? (b) What is the overall effect of previously conducted interventions on objectively measured PA? (c) What factors may influence the effect of interventions on objectively measured PA?
Methods The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement guided the literature search, conduct of the systematic review, and report of the findings (42). The PRISMA statement, including a 27-item checklist and a 4-phase flow diagram, specifies ways to ensure transparent and complete reporting of a review. The checklist addresses the content to be included in each section of the review, including title, abstract, introduction, methods, results, discussion, and funding. The flow diagram helps depict the number of records identified, included, and excluded; and reasons for exclusion. Due to the need for a comprehensive representation of evidence in the review, both randomized and nonrandomized quantitative studies incorporating a control or comparison group were analyzed (16).
PES Vol. 27, No. 3, 2015
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Data Sources and Search Strategy Assisted by a master-prepared university health science librarian, the first author developed the initial search strategy to determine the general quantity and quality of published studies testing PA interventions in children aged 2–5 years old in the PubMed database (from 1969). The following search terms and strategy were used: ((“Motor Activity”[Mesh]) OR (“Exercise”[Mesh]) OR (“Play and Playthings”[Mesh]) OR “physical activity” OR “exercise*” OR play*) AND ((“Intervention Studies”[Mesh]) OR intervention* OR program*) Filters: Humans; English; Preschool Child: 2–5 years. The procedure used for the PubMed database was adapted to create a database-specific search strategy for CINAHL (from 1978), PsycINFO (from 1889), ERIC (from 1966), SPORTDiscus (from 1976), Cochrane database of systematic reviews (from 1996), and Embase (from 1960). Because no filter or limit for age group existed in databases of ERIC, SPORTDiscus, and Cochrane database of systematic reviews, (preschool* OR toddler* OR child) was used to limit searching citations to children only. In May 2014, we carried out the full electronic search for published studies dating from their inception to 2014 in these 7 databases. To identify additional studies, we also reviewed reference lists of any relevant reviews and original studies. The objective was to ensure an exhaustive search for all international evidence associated with all disciplines and published in English.
Eligibility Criteria Studies were included in the review if they: (a) primarily targeted children of preschool age (2–5 years); (b) were original studies testing an intervention to increase PA or decrease sedentary activity in any setting; (c) included a control or comparison group; and (d) reported objectively measured PA as an outcome variable at baseline and postintervention. In this study, setting referred to the location where the intervention had been implemented. Exclusion criteria were: (a) secondary analysis; (b) abstract only; (c) protocol only; (d) review study; (e) entire population defined by a disease or a chronic condition such as autism, asthma, or obesity; and (f) sample size less than 30 participants.
Study Selection After exporting citations into the Endnote reference manager software, 2 authors (JL and FW) independently screened all titles and abstracts against the inclusion and exclusion criteria. After excluding citations that did not meet the inclusion criteria, they retrieved the full text of the retained citations. They independently conducted a second screening by reading the full version of each article and assessing whether
the retained articles met the inclusion criteria. They compared their findings and resolved any disagreement through discussion or, if necessary, consultation with the second author (LR).
Data Extraction To simplify the analysis of each study, the first author developed a data extraction form based on the Consolidated Standards of Reporting Trials (CONSORT) checklist (61). Details about each study’s sample and setting, design, intervention, PA measure, and results were extracted by the first author. All authors independently checked the extractions against the full text for accuracy. Any discrepancies were discussed until all authors reached agreement.
Quality Appraisal and Risk of Bias Each study was appraised based on the criteria adapted from the Cochrane Handbook for Systematic Reviews of Interventions (33). Two authors (JL and LR) independently evaluated each study and discussed any discrepancies until they agreed regarding the outcome. Risk of bias (yes: low risk of bias, no: high risk of bias, and unclear: insufficient information) was evaluated based on the following 4 quality indicators: (a) random sequence generation; (b) blinding of PA outcome assessment; (c) valid PA measure (≥ 3 days of data) (1); and (d) clear explanation of withdrawal. Only studies with no high risk of bias for all 4 indicators were considered low risk of bias.
Data Synthesis Examination of the included studies indicated substantial heterogeneity of the designs, outcome measures, and intervention components. Therefore, a narrative summary technique rather than a meta-analysis was used to report the findings according to the 3 research questions.
Results Study Selection A total of 11,559 citations were identified from the database searches and reference lists. After screening titles and abstracts and removing duplicates, 191 articles were retained. The second screening based on reading the full text yielded 24 articles focusing on increasing objectively measured PA in children aged 2–5 years old. Two articles described the same study, resulting in 23 independent studies; and 4 articles described one intervention but different studies, resulting in 20 unique interventions. Figure 1 presents the flow diagram depicting study selection results. Table 1 summarizes the 23 independent studies included in the review.
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RCT Duration: 8 months
• Setting: home • Sample: 400 parents with 2–5 yearold child Intervention: 200 parent-child dyads, 43.5% female. Control: 200 parent-child dyads, 45% female.
Duration: 16 weeks
• Country: Southern U.S.
• Sample: 40 parent-child dyads; children aged 1–3, mean age 1.8; 46% female; mothers mean age 26.5. OPPS Group: 20 parent-child dyads. PS Group: 20 parent-child dyads.
• Setting: home
• Parents received monthly newsletters emphasizing prereading skills.
Control
• Parents received monthly interactive kits. • 20–30 min MI coaching session/month.
• Monthly staff development sessions. Parenting Support (PS) Group • 11 parenting lesson topics focusing on child’s psychological and behavioral goals, logical and natural consequences, mutual respect, and encouragement techniques. • Peer educators received 120-hr training. • Monthly staff development sessions. Intervention
Obesity Prevention and Parenting Support (OPPS) Group • 11 parenting lesson topics focusing on eating and exercise behaviors. • Peer educators received 120-hr training.
• 60 min unstructured recess/day at playground: 30 min morning, 30 min afternoon. Control • Usual care.
MVPA: ³715 counts/15 s epoch
Actical accelerometer (Mini Mitter) 7 days minutes/ day
Vector magnitude/ hour
TriTrac R3D accelerometer 3 days
% of time MVPA: ³1594 counts/min
ActiGraph accelerometer 4 days
Recess Intervention
RCT Duration: 3 months
Measure
Intervention
Design
• Sample: 32 children aged 3–5 Intervention: 17 Latino children, mean age 3.8 (.5), 41.2% female. Control: 15 Latino children, mean age 3.5 (.5), 33.3% female. • Country: Canada RCT
• Setting: 1 Head Start center
Study* Sample Randomized Controlled Trial (RCT) 4 • Country: Western U.S.
Table 1 Study Summary: Sample, Design, Intervention, Measure, and Results (N = 23)
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(continued)
• Nonsignificant change in PA and sedentary activity.
• Nonsignificant change in PA at both groups.
• Nonsignificant change in sedentary activity, % of LPA, and % of MVPA.
Results
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Duration: 12 months Follow-up: 6, 12 months
• Setting: 11 childcare centers
• Sample: 178 children aged 3–5 Group 1: 45 children, mean age 4.0 (.6), 48.9% female, 2.2% Black. Group 2: 45 children, mean age 4.0 (.6), 46.7% female, 11.1% Black. Group 3: 43 children, mean age 3.9 (.6), 44.2% female, 7.0% Black. Groups 4: 45 children, mean age 3.8 (.5), 48.9% female, 4.4% Black.
• Setting: 2 preschool centers • Sample: 71 children aged 2.9–5 Intervention: 4 classrooms, 43 children, mean age 4.5 (.6), 49% female, 65% Hispanic, 35% Black. Control: 4 classrooms, 28 children, mean age 4.1 (.6), 54% female, 54% Hispanic, 46% Black.
Duration: 6 months
Cluster RCT
Design RCT
Sample • Country: Midwestern U.S.
Cluster RCT 2 • Country: Northeastern U.S.
Study* 63,64
Table 1 (continued)
• 30 min free play PA/day, 5 days/week. • Teachers received 2 hr training on free play.
• 30 min structured PA/day, 5 days/week. • Teachers received 8 hr training on structured PA. Control: Unstructured free playtime
Locomotor Skills-based Structured PA Program
• 30 min PA/day, 5 days/week; 5 min warm-up, 20 min jumping, hopping, and skipping activities, 5 min cool-down. • Two 500mg calcium tablets/day, 5 days/week. Cross motor + Placebo (Group 4) • 30 min PA/day, 5 days/week; 5 min warm-up, 20 min jumping, hopping, and skipping activities, 5 min cool-down.
Cross motor + Calcium (Group 3)
• 30 min/day sitting quietly.
• Two 500mg calcium tablets/day, 5 days/week. Fine motor + Placebo (Group 2)
• 30 min/day sitting quietly.
Intervention Fine motor + Calcium (Group 1)
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7 days % of time MVPA: ≥615 counts/ 15 s epoch
ActiGraph GT1M accelerometer
% of time, and counts/day
Measure Actiwatch Model AW16 activity monitor 2 days
(continued)
• Significant decrease in % of sedentary activity, 76.2 (5.5) to 73.7 (8.0) vs. 70.6 (7.0) to 74.7 (6.0), p=.01. • Nonsignificant change in % of LPA.
• Significant increase in % of VPA, and counts/day after intervention, and at 6-month follow-up. • Nonsignificant change at 12-month follow-up.
Results Gross Motor Group vs. Fine Motor Group
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6
Study* 5
Control: 38 classes.
• Setting: 98 YMCA preschool classes Duration: 9 months • Sample: 885–1154 children aged 4–5, mean age 4.4 (.5), 51.2% female, 86% Black. Intervention: 60 classes.
• Country: Southern U.S. Cluster RCT
Duration: 8 weeks
• Setting: 32 YMCA preschool classes • Sample: 275 Black children aged 3.5–5.6, mean age 4.6 (.5), 55.6% female. Intervention: 21 classes, 154 children.
Control: 11 classes, 121 children.
Design Cluster RCT
Sample • Country: Southern U.S.
Table 1 (continued)
MVPA:≥3 METs
• Teachers received 4-hr training, and a binder of daily lesson plans. • Teachers used ‘achievement charts’ to monitor children’s progress with stickers. Control • 30 min structured PA per day. Start For Life Intervention
1 day % of time
MVPA: ≥3 METs
• Self-efficacy theory and social cognitive theory. • 30 min structured PA per day.
• Teachers received 4-hr training, and a binder of daily lesson plans. • Teachers used ‘achievement charts’ to monitor children’s progress with stickers. Control • 30 min structured PA per day.
ActiGraph GT3× accelerometer
1 day % of time
Measure ActiGraph GT3× accelerometer
• Self-efficacy theory and social cognitive theory. • 30 min structured PA per day.
Intervention Start For Life Intervention
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(continued)
• Significant increase in % of MVPA, 23.9 (6.9) vs. 22.5 (4.8), p=.016; and % of VPA, 17.5 (5.5) vs. 15.7 (3.6), p
REVIEWS
Interventions to Increase Physical Activity in Children Aged 2-5 Years: A Systematic Review Jiying Ling Michigan State University
Lorraine B. Robbins Michigan State University
Fujun Wen Michigan State University
Wei Peng Michigan State University Comprehensive evaluation of prior interventions designed to increase preschoolers’ physical activity is lacking. This systematic review aimed to examine the effect of interventions on objectively measured physical activity in children aged 2–5 years. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. In May 2014, we searched PubMed, CINAHL, PsycINFO, ERIC, SPORTDiscus, Cochrane, and Embase. Two reviewers independently identified and appraised the studies. Twenty-four articles describing 23 independent studies and 20 unique interventions met inclusion criteria. Of the 8 interventions resulting in a significant effect in objectively measured physical activity, all were center-based and included a structured physical activity component, 6 included multiple components, 5 integrated theories or models, and 4 actively involved parents. Seven of the 8 were randomized controlled trials. Due to the heterogeneity of the study designs, physical activity measures, and interventions, drawing definitive conclusions was difficult. Although the overall intervention effect was less than optimal, the review indicated that theory-driven, multicomponent interventions including a structured physical activity component and targeting both parents and their children may be a promising approach for increasing preschoolers’ physical activity and warrant continued investigation using rigorous designs to identify those that are most effective. Keywords: review, exercise, preschool, program evaluation From 1990 to 2010, the worldwide prevalence of overweight and obesity among preschool children has increased from 4.2% to 6.7%, and is expected to reach 9.1% by 2020 (20). In the U.S., 22.8% of children, aged 2–5 years, are overweight or obese (50). Children who are overweight at age 5 are 4 times as likely as those of the same age with a healthy weight to become obese in either later childhood or adolescence (17). These Ling and Robbins are with the College of Nursing, Wen, the Dept. of Kinesiology, and Peng the Dept. of Media and Information, Michigan State University, East Lansing, MI. Address author correspondence to Jiying Ling at jiying.ling@ hc.msu.edu.
314
alarming findings indicate that excess body weight early in a child’s life may be strongly correlated with subsequent obesity risks. Children who participate in a physical activity (PA) and nutrition intervention at an earlier age (< 5 years) have greater weight loss over 2 years than those who participate in the same intervention at an older age (> 5 years) (15). Therefore, intervening before the start of elementary school holds promise in reversing the current epidemic of childhood obesity. PA is protective against obesity during the preschool years (57) and is essential for children’s physical, cognitive, social, and emotional development at all ages (28). Children aged 3–5 years who are inactive are 3.8 times more likely to gain subcutaneous fat than
Downloaded by York Univ Libraries on 09/19/16, Volume 27, Article Number 3
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those who are active (43). Preschoolers’ accelerometermeasured vigorous PA is significantly associated with their lower odds of being overweight (40). A recently conducted systematic review indicates that a high level of PA not only reduces adiposity, but also improves motor skill development and psychosocial and cardiovascular health in children aged 0–4 years (68). These studies support that important health benefits are accrued from PA. Although PA guidelines have been developed in several countries, the amount of daily PA recommended is inconsistent. Recommendations in Australia and the United Kingdom indicate that preschool children should participate in at least 3 hr of PA every day, including light, moderate, and vigorous PA (62). The U.S. National Association for Sport and Physical Education (NASPE) (45) guidelines call for 120 min of daily PA. Moreover, the U.S. Institute of Medicine (IOM) (35) recommends that preschool children should participate in 15 or more minutes of PA per hour, approximately 3 hr per day. Based on accelerometer data, preschool children actually participate in an average of 43 min of moderate to vigorous PA (MVPA) daily (13). Regardless of the guideline discrepancies, the majority of preschool children worldwide do not meet current PA recommendations (58,62,69). Conducting interventions during early childhood may be a promising approach for assisting children to establish a positive behavioral pattern that has the potential to continue into adulthood (66). Although many interventions have been conducted to increase PA in preschool children, current information on their overall impact, especially factors influencing the intervention effect, is lacking. Two systematic reviews only focus on PA interventions conducted in childcare center-based settings including daycare or childcare center, preschool, and nursery (39,70). One metaanalysis, including studies conducted before 2012, examined the effect of PA interventions in preschool children (30). Although childcare center-based settings provide an excellent location for PA interventions, examining interventions conducted at home or other community settings (e.g., church, park, outpatient clinic, or hospital) is also essential to acquire information for targeting children’s home and community environment. In all 3 reviews, PA was operationally defined and measured in a variety of ways including proxy reports. Due to the limited reliability and validity of proxy reports of PA (54), results of the 3 reviews may be questionable. Previous reviews focusing on identifying factors influencing the intervention effect have yielded somewhat contradictory findings. One review of 19 studies conducted in childcare center-based settings indicated that regular structured PA programs had a beneficial effect in increasing PA among preschoolers (70). In contrast, a meta-analysis of 15 studies showed
that short-term (< 4 weeks), teacher-led PA programs including outdoor activity and unstructured PA were most effective (30). Finally, another review that included 23 studies conducted in childcare center-based settings noted no effect of theory-based, multicomponent interventions (39). The inconsistent findings, possibly due to the heterogeneity of the included studies, limit the ability to draw conclusions regarding factors that influence the intervention effect. This paper adds to the existing body of knowledge by conducting a systematic review of all relevant PA intervention studies up to May 2014 that involve preschool-age children and include an objective measure of PA, such as pedometers and accelerometers. To efficiently inform future research efforts directed toward preventing obesity among older children and adolescents, effective and sustainable interventions and strategies targeting PA in preschool-age children need to be identified. Less biased than a narrative review, a systematic review can assist with achieving this objective by offering a rigorous and comprehensive examination of all studies addressing a specific topic (26), such as PA interventions among preschoolers.
Objective The aim was to examine the effect of interventions on objectively measured PA in children of preschool age. In this study, preschoolers represent children aged 2–5 years. Research questions were: (a) What types of interventions have been conducted to increase objectively measured PA in preschoolers? (b) What is the overall effect of previously conducted interventions on objectively measured PA? (c) What factors may influence the effect of interventions on objectively measured PA?
Methods The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement guided the literature search, conduct of the systematic review, and report of the findings (42). The PRISMA statement, including a 27-item checklist and a 4-phase flow diagram, specifies ways to ensure transparent and complete reporting of a review. The checklist addresses the content to be included in each section of the review, including title, abstract, introduction, methods, results, discussion, and funding. The flow diagram helps depict the number of records identified, included, and excluded; and reasons for exclusion. Due to the need for a comprehensive representation of evidence in the review, both randomized and nonrandomized quantitative studies incorporating a control or comparison group were analyzed (16).
PES Vol. 27, No. 3, 2015
316 Ling et al.
Downloaded by York Univ Libraries on 09/19/16, Volume 27, Article Number 3
Data Sources and Search Strategy Assisted by a master-prepared university health science librarian, the first author developed the initial search strategy to determine the general quantity and quality of published studies testing PA interventions in children aged 2–5 years old in the PubMed database (from 1969). The following search terms and strategy were used: ((“Motor Activity”[Mesh]) OR (“Exercise”[Mesh]) OR (“Play and Playthings”[Mesh]) OR “physical activity” OR “exercise*” OR play*) AND ((“Intervention Studies”[Mesh]) OR intervention* OR program*) Filters: Humans; English; Preschool Child: 2–5 years. The procedure used for the PubMed database was adapted to create a database-specific search strategy for CINAHL (from 1978), PsycINFO (from 1889), ERIC (from 1966), SPORTDiscus (from 1976), Cochrane database of systematic reviews (from 1996), and Embase (from 1960). Because no filter or limit for age group existed in databases of ERIC, SPORTDiscus, and Cochrane database of systematic reviews, (preschool* OR toddler* OR child) was used to limit searching citations to children only. In May 2014, we carried out the full electronic search for published studies dating from their inception to 2014 in these 7 databases. To identify additional studies, we also reviewed reference lists of any relevant reviews and original studies. The objective was to ensure an exhaustive search for all international evidence associated with all disciplines and published in English.
Eligibility Criteria Studies were included in the review if they: (a) primarily targeted children of preschool age (2–5 years); (b) were original studies testing an intervention to increase PA or decrease sedentary activity in any setting; (c) included a control or comparison group; and (d) reported objectively measured PA as an outcome variable at baseline and postintervention. In this study, setting referred to the location where the intervention had been implemented. Exclusion criteria were: (a) secondary analysis; (b) abstract only; (c) protocol only; (d) review study; (e) entire population defined by a disease or a chronic condition such as autism, asthma, or obesity; and (f) sample size less than 30 participants.
Study Selection After exporting citations into the Endnote reference manager software, 2 authors (JL and FW) independently screened all titles and abstracts against the inclusion and exclusion criteria. After excluding citations that did not meet the inclusion criteria, they retrieved the full text of the retained citations. They independently conducted a second screening by reading the full version of each article and assessing whether
the retained articles met the inclusion criteria. They compared their findings and resolved any disagreement through discussion or, if necessary, consultation with the second author (LR).
Data Extraction To simplify the analysis of each study, the first author developed a data extraction form based on the Consolidated Standards of Reporting Trials (CONSORT) checklist (61). Details about each study’s sample and setting, design, intervention, PA measure, and results were extracted by the first author. All authors independently checked the extractions against the full text for accuracy. Any discrepancies were discussed until all authors reached agreement.
Quality Appraisal and Risk of Bias Each study was appraised based on the criteria adapted from the Cochrane Handbook for Systematic Reviews of Interventions (33). Two authors (JL and LR) independently evaluated each study and discussed any discrepancies until they agreed regarding the outcome. Risk of bias (yes: low risk of bias, no: high risk of bias, and unclear: insufficient information) was evaluated based on the following 4 quality indicators: (a) random sequence generation; (b) blinding of PA outcome assessment; (c) valid PA measure (≥ 3 days of data) (1); and (d) clear explanation of withdrawal. Only studies with no high risk of bias for all 4 indicators were considered low risk of bias.
Data Synthesis Examination of the included studies indicated substantial heterogeneity of the designs, outcome measures, and intervention components. Therefore, a narrative summary technique rather than a meta-analysis was used to report the findings according to the 3 research questions.
Results Study Selection A total of 11,559 citations were identified from the database searches and reference lists. After screening titles and abstracts and removing duplicates, 191 articles were retained. The second screening based on reading the full text yielded 24 articles focusing on increasing objectively measured PA in children aged 2–5 years old. Two articles described the same study, resulting in 23 independent studies; and 4 articles described one intervention but different studies, resulting in 20 unique interventions. Figure 1 presents the flow diagram depicting study selection results. Table 1 summarizes the 23 independent studies included in the review.
PES Vol. 27, No. 3, 2015
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RCT Duration: 8 months
• Setting: home • Sample: 400 parents with 2–5 yearold child Intervention: 200 parent-child dyads, 43.5% female. Control: 200 parent-child dyads, 45% female.
Duration: 16 weeks
• Country: Southern U.S.
• Sample: 40 parent-child dyads; children aged 1–3, mean age 1.8; 46% female; mothers mean age 26.5. OPPS Group: 20 parent-child dyads. PS Group: 20 parent-child dyads.
• Setting: home
• Parents received monthly newsletters emphasizing prereading skills.
Control
• Parents received monthly interactive kits. • 20–30 min MI coaching session/month.
• Monthly staff development sessions. Parenting Support (PS) Group • 11 parenting lesson topics focusing on child’s psychological and behavioral goals, logical and natural consequences, mutual respect, and encouragement techniques. • Peer educators received 120-hr training. • Monthly staff development sessions. Intervention
Obesity Prevention and Parenting Support (OPPS) Group • 11 parenting lesson topics focusing on eating and exercise behaviors. • Peer educators received 120-hr training.
• 60 min unstructured recess/day at playground: 30 min morning, 30 min afternoon. Control • Usual care.
MVPA: ³715 counts/15 s epoch
Actical accelerometer (Mini Mitter) 7 days minutes/ day
Vector magnitude/ hour
TriTrac R3D accelerometer 3 days
% of time MVPA: ³1594 counts/min
ActiGraph accelerometer 4 days
Recess Intervention
RCT Duration: 3 months
Measure
Intervention
Design
• Sample: 32 children aged 3–5 Intervention: 17 Latino children, mean age 3.8 (.5), 41.2% female. Control: 15 Latino children, mean age 3.5 (.5), 33.3% female. • Country: Canada RCT
• Setting: 1 Head Start center
Study* Sample Randomized Controlled Trial (RCT) 4 • Country: Western U.S.
Table 1 Study Summary: Sample, Design, Intervention, Measure, and Results (N = 23)
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(continued)
• Nonsignificant change in PA and sedentary activity.
• Nonsignificant change in PA at both groups.
• Nonsignificant change in sedentary activity, % of LPA, and % of MVPA.
Results
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Duration: 12 months Follow-up: 6, 12 months
• Setting: 11 childcare centers
• Sample: 178 children aged 3–5 Group 1: 45 children, mean age 4.0 (.6), 48.9% female, 2.2% Black. Group 2: 45 children, mean age 4.0 (.6), 46.7% female, 11.1% Black. Group 3: 43 children, mean age 3.9 (.6), 44.2% female, 7.0% Black. Groups 4: 45 children, mean age 3.8 (.5), 48.9% female, 4.4% Black.
• Setting: 2 preschool centers • Sample: 71 children aged 2.9–5 Intervention: 4 classrooms, 43 children, mean age 4.5 (.6), 49% female, 65% Hispanic, 35% Black. Control: 4 classrooms, 28 children, mean age 4.1 (.6), 54% female, 54% Hispanic, 46% Black.
Duration: 6 months
Cluster RCT
Design RCT
Sample • Country: Midwestern U.S.
Cluster RCT 2 • Country: Northeastern U.S.
Study* 63,64
Table 1 (continued)
• 30 min free play PA/day, 5 days/week. • Teachers received 2 hr training on free play.
• 30 min structured PA/day, 5 days/week. • Teachers received 8 hr training on structured PA. Control: Unstructured free playtime
Locomotor Skills-based Structured PA Program
• 30 min PA/day, 5 days/week; 5 min warm-up, 20 min jumping, hopping, and skipping activities, 5 min cool-down. • Two 500mg calcium tablets/day, 5 days/week. Cross motor + Placebo (Group 4) • 30 min PA/day, 5 days/week; 5 min warm-up, 20 min jumping, hopping, and skipping activities, 5 min cool-down.
Cross motor + Calcium (Group 3)
• 30 min/day sitting quietly.
• Two 500mg calcium tablets/day, 5 days/week. Fine motor + Placebo (Group 2)
• 30 min/day sitting quietly.
Intervention Fine motor + Calcium (Group 1)
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7 days % of time MVPA: ≥615 counts/ 15 s epoch
ActiGraph GT1M accelerometer
% of time, and counts/day
Measure Actiwatch Model AW16 activity monitor 2 days
(continued)
• Significant decrease in % of sedentary activity, 76.2 (5.5) to 73.7 (8.0) vs. 70.6 (7.0) to 74.7 (6.0), p=.01. • Nonsignificant change in % of LPA.
• Significant increase in % of VPA, and counts/day after intervention, and at 6-month follow-up. • Nonsignificant change at 12-month follow-up.
Results Gross Motor Group vs. Fine Motor Group
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Study* 5
Control: 38 classes.
• Setting: 98 YMCA preschool classes Duration: 9 months • Sample: 885–1154 children aged 4–5, mean age 4.4 (.5), 51.2% female, 86% Black. Intervention: 60 classes.
• Country: Southern U.S. Cluster RCT
Duration: 8 weeks
• Setting: 32 YMCA preschool classes • Sample: 275 Black children aged 3.5–5.6, mean age 4.6 (.5), 55.6% female. Intervention: 21 classes, 154 children.
Control: 11 classes, 121 children.
Design Cluster RCT
Sample • Country: Southern U.S.
Table 1 (continued)
MVPA:≥3 METs
• Teachers received 4-hr training, and a binder of daily lesson plans. • Teachers used ‘achievement charts’ to monitor children’s progress with stickers. Control • 30 min structured PA per day. Start For Life Intervention
1 day % of time
MVPA: ≥3 METs
• Self-efficacy theory and social cognitive theory. • 30 min structured PA per day.
• Teachers received 4-hr training, and a binder of daily lesson plans. • Teachers used ‘achievement charts’ to monitor children’s progress with stickers. Control • 30 min structured PA per day.
ActiGraph GT3× accelerometer
1 day % of time
Measure ActiGraph GT3× accelerometer
• Self-efficacy theory and social cognitive theory. • 30 min structured PA per day.
Intervention Start For Life Intervention
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(continued)
• Significant increase in % of MVPA, 23.9 (6.9) vs. 22.5 (4.8), p=.016; and % of VPA, 17.5 (5.5) vs. 15.7 (3.6), p
