A mixed-studies systematic review and meta-analysis of school-based interventions to promote physical activity and/or reduce sedentary time in children

In the paper

“it is widely reported that the majority of children do not meet these guidelines.”

What the sources say

• Supported

  The Discussion concludes that most children in the large multinational sample did not achieve the daily MVPA guidelines. The Results report that only 4.8% met them on all seven days, supporting the citing sentence’s broad statement. (LLM, conf=0.94)

  cites [3] Gomes, 2017, Correlates of compliance with recommended levels of physical activity in children, Sci Rep source
• Supported

  The Overall Physical Activity section reports low (D) grades in 20 countries and failing (F) grades in seven, describing widespread childhood physical inactivity. Table 2 defines this indicator by the percentage of children and youth meeting physical activity guidelines, so the reported grades support the claim. Page numbers were not available in our copy. (LLM, conf=0.93)

  cites [4] Tremblay, 2016, Global matrix 2.0: report card grades on the physical activity of children and youth comparing 38 countries, J Phys Act Health source

In the paper

“This most commonly took the form of a combination of expanding and enhancing PA opportunities, but overall these approaches led to an inconclusive evidence rating of MVPA.63, 65, 74, 77, 81, 82, 85,88, 89, 90,93, 96, 97, 101, 108”

What the sources say

• Partly supported

  The Methods (Intervention; page not provided) describe a multicomponent school programme, and the Results and Discussion (pages not provided) report no evidence that it increased accelerometer-assessed MVPA. This trial supports a null finding for AFLY5, but it does not assign an overall inconclusive evidence rating to multicomponent approaches. (LLM, conf=0.84)

  cites [63] Kipping, 2014, Effect of intervention aimed at increasing physical activity, reducing sedentary behaviour, and increasing fruit and vegetable consumption in children: active for life year 5 (AFLY5) school-based cluster randomised controlled trial, BMJ sourceExperimental — accuracy not yet measured
• Supported

  The Methods (Intervention objectives and implementation) describe a multicomponent approach combining PE, recess, and activity integrated into lessons. The Results (Physical activity—accelerometers) report increased school-hours MVPA after one year but no significant difference at the end of two years. This study therefore supplies an example of mixed MVPA findings underlying the citing authors’ overall evidence rating; it does not itself assign that rating. (LLM, conf=0.86)

  cites [65] Magnusson, 2011, Assessment of a two-year school-based physical activity intervention among 7-9-year-old children, Int J Behav Nutr Phys Act source
• Partly supported

  The Discussion (page unavailable) identifies Fit-4-Fun as a multicomponent school-based intervention. The Changes in primary and secondary outcomes section reports increased activity in steps per day, while Study strengths and limitations explains that pedometers did not measure activity intensity. The paper therefore supports including this trial as a multicomponent example, but does not provide an MVPA-specific result or an overall evidence rating. (LLM, conf=0.83)

  cites [74] Eather, 2013, Improving the fitness and physical activity levels of primary school children: results of the fit-4-fun group randomized controlled trial, Prev Med sourceExperimental — accuracy not yet measured

In the paper

“A number of studies combined aspects of the TEO in a multicomponent approach.64, 91, 99”

What the sources say

• Supported

  The Methods > Intervention section says the KISS programme was based on a socio-ecological conceptual model, targeted both class and individual levels, and combined lessons, activity breaks, and homework. The Discussion > Conclusions section explicitly calls it a multi-component intervention. The paper therefore supports its use as one example among the studies cited. (LLM, conf=0.90)

  cites [64] Kriemler, 2010, Effect of school based physical activity programme (KISS) on fitness and adiposity in primary schoolchildren: cluster randomised controlled trial, BMJ source
• Not checked yetcites [91] Pangrazi, 2003, Impact of promoting lifestyle activity for youth (PLAY) on children's physical activity, J Sch Health source
• Not checked yetcites [99] Dauenhauer, 2016, Effects of a three-tiered intervention model on physical activity and fitness levels of elementary school children, J Prim Prev source

In the paper

“The evidence regarding the use of differing intervention types to expand PA opportunity was inconsistent.”

In the paper

“A positive effect on PA was reported in 68% of the 57 studies.”

In the paper

“Focusing specifically on those studies that measured MVPA (37 studies), 62% indicated a positive effect.”

In the paper

“The sample size of children with objectively assessed PA and/or ST was < 250 in 30 studies,47, 49, 51, 52, 55, 56,58, 59, 60,65, 66,70, 71, 72, 73, 74,78, 79, 83, 84, 87, 89, 90, 94, 95,98, 99, 100,102, 103”

In the paper

“Overall, the evidence rating for ST was inconclusive.”

• Also stated in: § Abstract · plain

  “Overall evidence ratings for interventions implemented within school settings showed no evidence of effects of moderate-to-vigorous physical activity and inconclusive evidence of effects of sedentary time.”

In the paper

“Sensitivity analysis revealed a substantial reduction in magnitude and increase in the precision of the estimate upon removal of Howe et al.84 (–0.05; 95%CI: –0.12 to 0.02).”

What the sources say

• Not checked yetcites Howe et al.84 Howe, 2012, A recess intervention to promote moderate-to-vigorous physical activity, Pediatr Obes source

In the paper

“The funnel plot for studies reporting MVPA outcomes identified 2 studies as clear outliers.”

In the paper

“When intervention effectiveness was measured during the school day, 76% of the 16 studies reported a positive effect for MVPA or step count.”

In the paper

“When intervention effectiveness was measured during actual intervention delivery, 100% of the 9 studies reported a positive effect, with moderate evidence of effect for MVPA and inconclusive evidence for step count.”

In the paper

“The mixed-effect meta regression model showed that the interventions with an MVPA measure were not associated with study type (coefficient = 0.49 ± 1.19, p = 0.4252) or study quality (coefficient = –0.13 ± 1.18, p = 0.8299).”

In the paper

“Overall, the systematic review identified no evidence of effect for MVPA and inconclusive evidence for ST.”

In the paper

“Publication bias analysis using the Egger regression asymmetry test suggested evidence of publication bias for MVPA (z = 4.3749, p < 0.0001).”

In the paper

“When intervention effectiveness was measured during actual intervention delivery, 100% of the 9 studies reported a positive effect, with moderate evidence of effect for MVPA and inconclusive evidence for step count.”

In the paper

“When intervention effectiveness was measured during actual intervention delivery, 100% of the 9 studies reported a positive effect, with moderate evidence of effect for MVPA and inconclusive evidence for step count.”

In the paper

“The majority of studies reported outcomes for the whole sample of participants or by grade, irrespective of participants’ characteristics.”

In the paper

“The quality and nature of evidence led to an overall rating of inconclusive evidence for MVPA and step count when intervention effectiveness was measured during the school day.”

In the paper

“A differential response to intervention based on sex was identified in 6 studies,53, 54, 65, 75, 79, 91 including 1 large high-quality RCT75 and 2 large low-quality RCTs.53, 54”

What the sources say

• Not checked yetcites [53] Huberty, 2011, Environmental modifications to increase physical activity during recess: preliminary findings from ready for recess, J Phys Act Health source
• Not checked yetcites [54] Huberty, 2014, Effects of ready for recess, an environmental intervention, on physical activity in third- through sixth-grade children, J Phys Act Health source
• Not checked yetcites [75] Naylor, 2008, An active school model to promote physical activity in elementary schools: action schools! BC, Br J Sports Med source

In the paper

“The mixed-effect meta regression model showed that the interventions with an MVPA measure were not associated with study type (coefficient = 0.49 ± 1.19, p = 0.4252) or study quality (coefficient = –0.13 ± 1.18, p = 0.8299).”

In the paper

“In fact, 5 RCTs and 2 NR studies reported that the significant effect of the intervention was aligned with preventing, or at least reducing, the decline in PA observed in control conditions over time, rather than significantly increasing PA in intervention conditions per se.55, 58, 66, 70, 73, 81, 82”

What the sources say

• Not checked yetcites [55] Martin, 2017, Active classrooms: a cluster randomized controlled trial evaluating the effects of a movement integration intervention on the physical activity levels of primary school children, J Phys Act Health source
• Not checked yetcites [58] Crouter, 2015, Effect on physical activity of a randomized afterschool intervention for inner city children in 3rd to 5th grade, PLoS One source
• Not checked yetcites [66] Mendoza, 2011, The walking school bus and children's physical activity: a pilot cluster randomized controlled trial, Pediatrics source

In the paper

“Overall, the systematic review identified no evidence of effect for MVPA and inconclusive evidence for ST.”

In the paper

“2 studies included in this review reinforced a larger effect for the least active participants.71, 102”

What the sources say

• Not checked yetcites [71] Kang, 2009, Effects of group and individual-based step goals on children's physical activity levels in school, Pediatr Exerc Sci source
• Not checked yetcites [102] Oliver, 2006, An integrated curriculum approach to increasing habitual physical activity in children: a feasibility study, J Sch Health source

In the paper

“When PA was measured over a whole day (excluding sleep), the reported effectiveness of the intervention was lower, with 58% (19 of 33 studies) reporting a positive effect for MVPA or step count.”

In the paper

“Expanded PA opportunity was a more promising intervention approach (moderate evidence rating) than extending (inconclusive evidence rating) or enhancing (no evidence rating) PA opportunity.”

In the paper

“Extending PA opportunities via increasing PE time62, 69, 79 or increasing recess time51, 78 led to an inconclusive evidence rating.”

What the sources say

• Not checked yetcites [62] Going, 2003, The effects of the pathways obesity prevention program on physical activity in American Indian children, Prev Med source
• Not checked yetcites [69] Sallis, 1997, The effects of a 2-year physical education program (SPARK) on physical activity and fitness in elementary school students, Am J Public Health source
• Not checked yetcites [79] Weaver, 2018, Partnerships for active children in elementary schools: outcomes of a 2-year pilot study to increase physical activity during the school day, Am J Health Promot source

In the paper

“Similarly, for active travel, the optional nature of the PA is exemplified; Heelan et al.83 found that just over a third of children actively commuted at least half of the time as a consequence of the intervention.”

What the sources say

• Not checked yetcites Heelan et al.83 Heelan, 2009, Evaluation of a walking school bus for promoting physical activity in youth, J Phys Act Health source

In the paper

“the mean difference between baseline and postintervention for MVPA and ST, respectively, was –5.0 ± 12.2 min and 15.1 ± 63.4 min in the control groups vs. 1.8 ± 16.5 min and 3.4 ± 62.1 min in the intervention groups.”

In the paper

“Physically active learning differs from class PA breaks in that PA was integrated into core English and math curriculum learning in the 2 high-quality, small RCTs that identified positive impact on MVPA.55, 56”

What the sources say

• Not checked yetcites [55] Martin, 2017, Active classrooms: a cluster randomized controlled trial evaluating the effects of a movement integration intervention on the physical activity levels of primary school children, J Phys Act Health source
• Not checked yetcites [56] Riley, 2015, Findings from the easy minds cluster randomized controlled trial: evaluation of a physical activity integration program for mathematics in primary schools, J Phys Act Health source

In the paper

“the mean difference between baseline and postintervention for MVPA and ST, respectively, was –5.0 ± 12.2 min and 15.1 ± 63.4 min in the control groups vs. 1.8 ± 16.5 min and 3.4 ± 62.1 min in the intervention groups.”

In the paper

“However, in 2 low-quality studies, extending recess time did lead to increases in MVPA.51, 78”

What the sources say

• Not checked yetcites [51] Verstraete, 2006, Increasing children's physical activity levels during recess periods in elementary schools: the effects of providing game equipment, Eur J Public Health source
• Not checked yetcites [78] Johnstone, 2017, Pragmatic evaluation of the Go2Play Active Play intervention on physical activity and fundamental movement skills in children, Prev Med Rep source

In the paper

“However, these enhancements led to an inconclusive evidence rating of MVPA.”

In the paper

“The methodological quality of studies included in our review was variable”

In the paper

“nor, indeed, were adherence levels reported”

In the paper

“A number of studies used objective PA assessment only in a subpopulation”

What the sources say

• Not checked yetcites [62] Going, 2003, The effects of the pathways obesity prevention program on physical activity in American Indian children, Prev Med source
• Not checked yetcites [70] Verstraete, 2007, A comprehensive physical activity promotion programme at elementary school: the effects on physical activity, physical fitness and psychosocial correlates of physical activity, Public Health Nutr source
• Not checked yetcites [76] Ridgers, 2007, Children's physical activity levels during school recess: a quasi-experimental intervention study, Int J Behav Nutr Phys Act source
• Not checked yetcites [78] Johnstone, 2017, Pragmatic evaluation of the Go2Play Active Play intervention on physical activity and fundamental movement skills in children, Prev Med Rep source
• Not checked yetcites [83] Heelan, 2009, Evaluation of a walking school bus for promoting physical activity in youth, J Phys Act Health source
• Not checked yetcites [95] Holt, 2013, Evaluation of a policy to integrate physical activity into the school day, J Phys Act Health source

In the paper

“Indeed, 24 of the 57 studies reviewed were identified via secondary search strategies.”

In the paper

“there was no overall pattern in the results”

In the paper

“the majority of studies did not report any tailoring or modifications of the intervention design or delivery”

In the paper

“Whilst a small number of studies considered sex differences in terms of intervention effectiveness”

What the sources say

• Not checked yetcites [53] Huberty, 2011, Environmental modifications to increase physical activity during recess: preliminary findings from ready for recess, J Phys Act Health source
• Not checked yetcites [54] Huberty, 2014, Effects of ready for recess, an environmental intervention, on physical activity in third- through sixth-grade children, J Phys Act Health source
• Not checked yetcites [65] Magnusson, 2011, Assessment of a two-year school-based physical activity intervention among 7-9-year-old children, Int J Behav Nutr Phys Act source
• Not checked yetcites [75] Naylor, 2008, An active school model to promote physical activity in elementary schools: action schools! BC, Br J Sports Med source
• Not checked yetcites [79] Weaver, 2018, Partnerships for active children in elementary schools: outcomes of a 2-year pilot study to increase physical activity during the school day, Am J Health Promot source
• Not checked yetcites [91] Pangrazi, 2003, Impact of promoting lifestyle activity for youth (PLAY) on children's physical activity, J Sch Health source

In the paper

“There was no evidence of effect when measured over the course of a whole day”

In the paper

“it led to differential evidence ratings, with moderate evidence for expansion, inconclusive evidence for extension, and no evidence for enhancement of PA opportunity”

In the paper

“After-school clubs, active travel, class PA breaks, and physically active learning appeared to be the most promising interventions”

In the paper

“The current review identified no evidence of effect on MVPA for interventions aimed at children and implemented within school settings”

In the paper

“When studies measured changes in PA during the actual intervention, there was moderate evidence of effect”

In the paper

“some interventions specifically sought to prevent or reduce the decline in PA observed in control conditions over time, as opposed to significantly increasing PA in intervention conditions”

What the sources say

• Not checked yetcites [55] Martin, 2017, Active classrooms: a cluster randomized controlled trial evaluating the effects of a movement integration intervention on the physical activity levels of primary school children, J Phys Act Health source
• Not checked yetcites [58] Crouter, 2015, Effect on physical activity of a randomized afterschool intervention for inner city children in 3rd to 5th grade, PLoS One source
• Not checked yetcites [66] Mendoza, 2011, The walking school bus and children's physical activity: a pilot cluster randomized controlled trial, Pediatrics source
• Not checked yetcites [70] Verstraete, 2007, A comprehensive physical activity promotion programme at elementary school: the effects on physical activity, physical fitness and psychosocial correlates of physical activity, Public Health Nutr source
• Not checked yetcites [73] Duncan, 2011, Efficacy of a compulsory homework programme for increasing physical activity and healthy eating in children: the healthy homework pilot study, Int J Behav Nutr Phys Act source
• Not checked yetcites [81] Carson, 2014, Impact of trained champions of comprehensive school physical activity programs on school physical activity offerings, youth physical activity and sedentary behaviours, Prev Med source
• Not checked yetcites [82] Gorely, 2009, Effect of a school-based intervention to promote healthy lifestyles in 7-11 year old children, Int J Behav Nutr Phys Act source

In the paper

“there was inconclusive evidence of effect on ST”

In the paper

“it led to differential evidence ratings, with moderate evidence for expansion, inconclusive evidence for extension, and no evidence for enhancement of PA opportunity”

In the paper

“The measurement device, time period of measurement, and analysis methods, including cut-points for thresholds, varied substantially across studies”

In the paper

“there was inconclusive evidence of changes in PA when changes were measured during the school day”

In the paper

“it led to differential evidence ratings, with moderate evidence for expansion, inconclusive evidence for extension, and no evidence for enhancement of PA opportunity”

In the paper

“evidence suggests a decline in MVPA after early childhood,8, 9, 10”

What the sources say

• Not checked yetcites [8] Farooq, 2018, Timing of the decline in physical activity in childhood and adolescence: gateshead millennium cohort study, Br J Sports Med source
• Not checked yetcites [9] Cooper, 2015, Objectively measured physical activity and sedentary time in youth: the International Children's Accelerometry Database (ICAD), Int J Behav Nutr Phys Act source
• Not checked yetcites [10] Jago, 2017, Change in children's physical activity and sedentary time between year 1 and year 4 of primary school in the B-PROACT1V cohort, Int J Behav Nutr Phys Act source

In the paper

“a recent review found that less than 5% of 9- to 11-year-olds across 12 countries met the guidelines,3”

What the sources say

• Not checked yetcites [3] Gomes, 2017, Correlates of compliance with recommended levels of physical activity in children, Sci Rep source

In the paper

“There are also concerns about coexisting sedentary behavior (SB) in children, which is independently associated with poorer health outcomes.5”

What the sources say

• Not checked yetcites [5] Carson, 2016, Systematic review of sedentary behaviour and health indicators in school-aged children and youth: an update, Appl Physiol Nutr Metab source

In the paper

“longitudinal research, albeit in single countries, supports a decline in MVPA after early childhood.10”

What the sources say

• Not checked yetcites [10] Jago, 2017, Change in children's physical activity and sedentary time between year 1 and year 4 of primary school in the B-PROACT1V cohort, Int J Behav Nutr Phys Act source

In the paper

“the majority of existing systematic reviews have included only randomised controlled trials (RCTs)16, 17, 20 and/or controlled trials.19, 30, 31, 34”

What the sources say

• Not checked yetcites [16] Dobbins, 2013, School-based physical activity programs for promoting physical activity and fitness in children and adolescents aged 6 to 18, Cochrane Database Syst Rev
• Not checked yetcites [17] Hynynen, 2016, A systematic review of school-based interventions targeting physical activity and sedentary behaviour among older adolescents, Int Rev Sport Exerc Psychol source
• Not checked yetcites [20] Borde, 2017, Methodologicalal considerations and impact of school-based interventions on objectively measured physical activity in adolescents: a systematic review and meta-analysis, Obes Rev source

In the paper

“children spend 40% of their waking time at school.13”

What the sources say

• Not checked yetcites [13] Fox, 2004, The school and promotion of children's health-enhancing physical activity: perspectives from the United Kingdom, J Teach Phys Educ source

In the paper

“School has been identified as an important setting in which to promote MVPA and limit ST, particularly since children spend 40% of their waking time at school.13”

What the sources say

• Not checked yetcites [13] Fox, 2004, The school and promotion of children's health-enhancing physical activity: perspectives from the United Kingdom, J Teach Phys Educ source

In the paper

“Few systematic reviews have considered SB interventions within a school setting.17, 18, 35”

What the sources say

• Not checked yetcites [17] Hynynen, 2016, A systematic review of school-based interventions targeting physical activity and sedentary behaviour among older adolescents, Int Rev Sport Exerc Psychol source
• Not checked yetcites [18] Morton, 2016, The school environment and adolescent physical activity and sedentary behaviour: a mixed-studies systematic review, Obes Rev source
• Not checked yetcites [35] van Grieken, 2012, Primary prevention of overweight in children and adolescents: a meta-analysis of the effectiveness of interventions aiming to decrease sedentary behaviour, Int J Behav Nutr Phys Act source

In the paper

“there are no systematic reviews that focus exclusively on children.”

In the paper

“Whilst RCTs are at the upper end of the hierarchy of evidence in terms of causal inference regarding the efficacy or effectiveness of interventions, they cannot explore the complex nature of PA interventions in the school context.12”

What the sources say

• Not checked yetcites [12] Brown, 2014, Family-based interventions to increase physical activity in children: a meta-analysis and realist synthesis protocol, BMJ Open source

In the paper

“Heterogeneity of outcome measurement device, time frame (specific activities, school day, and whole day), analysis (cut-points), varied methodological quality, and research design made an overall meta-analysis inappropriate.”

In the paper

“Expansion of opportunities for physical activity, including after-school clubs, active travel, class physical activity breaks, and physically active learning appeared to be the most promising types of intervention.”

In the paper

“There was evidence of a moderate effect on physical activity measured during actual interventions, but this was not replicated across the whole day, suggesting compensatory behaviors.”

In the paper

“and Timperio et al.29 found that 6 of 9 studies (67%) based in primary schools had a positive effect.”

What the sources say

• Not checked yetcites Timperio et al.29 Timperio, 2004, Evidence-based strategies to promote physical activity among children, adolescents and young adults: review and update, J Sci Med Sport source

In the paper

“Specifically, Salmon et al.28 found that 12 of 18 studies (67%) with objective measures of PA reported a positive effect in children”

What the sources say

• Not checked yetcites Salmon et al.28 Salmon, 2007, Promoting physical activity participation among children and adolescents, Epidemiol Rev source

In the paper

“The time frame for measurement appeared to influence the reported outcomes, irrespective of the type of intervention applied.”

In the paper

“The differing implementation times may explain the effects in terms of preventing a decline in PA or ST.”

In the paper

“Moreover, interventions conducted over shorter durations (i.e., <12 weeks) could arguably be more subject to the impact of seasonal changes.105, 106”

What the sources say

• Not checked yetcites [105] Rowlands, 2009, Seasonal changes in children's physical activity: an examination of group changes, intra-individual variability and consistency in activity pattern across season, Ann Hum Biol source
• Not checked yetcites [106] Harrison, 2015, The changing relationship between rainfall and children's physical activity in spring and summer: a longitudinal study, Int J Behav Nutr Phys Act source

In the paper

“Our review of these studies resulted in an inconclusive evidence rating on MVPA; thus, even comprehensive multicomponent programmes based in school settings may have little effect on children's PA.”

In the paper

“Within school settings, enhancing existing PA opportunities alone does not appear to be an effective evidence-based strategy to promote PA among children.”

In the paper

“A number of existing systematic reviews of school-based PA interventions,28, 104 as well as Beets et al.,37 highlighted the potential risk that the intervention might increase PA during actual intervention delivery but result in a compensatory decline elsewhere during the day.”

What the sources say

• Not checked yetcites [28] Salmon, 2007, Promoting physical activity participation among children and adolescents, Epidemiol Rev source
• Not checked yetcites [104] Metcalf, 2012, Effectiveness of intervention on physical activity of children: systematic review and meta-analysis of controlled trials with objectively measured outcomes (EarlyBird 54), BMJ source
• Not checked yetcites Beets et al.37 Beets, 2016, The theory of expanded, extended, and enhanced opportunities for youth physical activity promotion, Int J Behav Nutr Phys Act source

In the paper

“Nonetheless, the thorough process of searching for secondary references most likely rectified this limitation.”

In the paper

“However, 1 limitation of the current review was the relatively limited nature of the initial literature search, in that it did not include search terms related to specific intervention types or to sex.”

In the paper

“Specifically, a systematic review of RCTs with objective, whole-day accelerometer PA measurements published after the search strategy was completed109 included a final sample of 17 studies.”

What the sources say

• Not checked yetcites [109] Love, 2019, Are school-based physical activity interventions effective and equitable? A meta-analysis of cluster randomized controlled trials with accelerometer-assessed activity, Obes Rev source

In the paper

“which suggests sex-specific interventions do not appear to be warranted”

In the paper

“For example, there is evidence that PA interventions with sufficiently high-intensity effort PA during intervention periods may increase cardiorespiratory fitness in children.111”

What the sources say

• Not checked yetcites [111] Tuvey S, Steele J, Horton E, Mayo X, Liguori G, Mann S, et al. Do changes in cardiorespiratory fitness resulting from physical activity interventions impact academic performance and executive function in children and adolescents? A systematic review, meta-analysis, and meta-regression. preprint. Available at: https://osf.io/preprints/sportrxiv/4j2sa/. [accessed 04.03.2019].

In the paper

“Indeed, expanded opportunities for PA, such as after-school clubs, have been reported to result in high levels of energy expenditure thought to be sufficient to stimulate improved cardiorespiratory fitness, both with traditional activities (i.e., soccer and netball) and novel activities (i.e., trampoline-park sessions).112”

What the sources say

• Not checked yetcites [112] Budzynski-Seymour, 2019, Heart rate, energy expenditure, and affective responses from children participating in trampoline park sessions compared with traditional extra-curricular sports clubs, J Sports Med Phys Fitness source

In the paper

“which may have introduced selection bias”

What the sources say

• Not checked yetcites [62] Going, 2003, The effects of the pathways obesity prevention program on physical activity in American Indian children, Prev Med source
• Not checked yetcites [70] Verstraete, 2007, A comprehensive physical activity promotion programme at elementary school: the effects on physical activity, physical fitness and psychosocial correlates of physical activity, Public Health Nutr source
• Not checked yetcites [76] Ridgers, 2007, Children's physical activity levels during school recess: a quasi-experimental intervention study, Int J Behav Nutr Phys Act source
• Not checked yetcites [78] Johnstone, 2017, Pragmatic evaluation of the Go2Play Active Play intervention on physical activity and fundamental movement skills in children, Prev Med Rep source
• Not checked yetcites [83] Heelan, 2009, Evaluation of a walking school bus for promoting physical activity in youth, J Phys Act Health source
• Not checked yetcites [95] Holt, 2013, Evaluation of a policy to integrate physical activity into the school day, J Phys Act Health source

In the paper

“The analysis of response on the basis of outcome measurement duration provides some support for the ActivityStat hypothesis, which suggests that increases in PA in 1 domain cause a compensatory reduction in another.110”

What the sources say

• Not checked yetcites [110] Ridgers, 2014, Compensation of physical activity and sedentary time in primary school children, Med Sci Sports Exerc source

In the paper

“which collectively weakens confidence in generating firm conclusions regarding effectiveness”