Classroom Movement That Counts: A Chilean Trial Tests Curriculum-Integrated Active Breaks to Boost Motor Skills, Fitness, Learning and Healthy Habits in Preschoolers

Table of Contents

1. Key Highlights
2. Introduction
3. Why preschool active breaks deserve serious attention
4. Designing active breaks that integrate with the curriculum
5. Trial design: three-arm, cluster-controlled and pragmatic
6. Measuring what matters: primary and secondary outcomes
7. Dose matters: comparing high and moderate frequency
8. Digital platform support and inclusive materials
9. Mixed-methods sequencing: why QUAN → qual adds value
10. Anticipated impacts and plausible pathways of effect
11. Implementation realities: barriers, facilitators and strategies
12. Ethical and equity considerations
13. How the Chilean context shapes the study and its implications
14. Potential limitations and how the study addresses them
15. Expected contributions to research and practice
16. Bringing active breaks into everyday preschool practice: a practical roadmap
17. Real-world examples that illuminate potential outcomes
18. Next steps and scaling considerations if results are positive
19. FAQ

Key Highlights

• A three-arm, non-randomized cluster-controlled trial in Biobío, Chile will test a 16-week curriculum-integrated active break program in 12 urban public preschools, comparing high-dose (10 breaks/week), moderate-dose (3–5 breaks/week) and control conditions in 200 five- to six-year-old children.
• Primary outcomes are motor competence and health-related physical fitness; secondary outcomes include learning outcomes and healthy habits (sleep, eating behavior, nutritional status). The trial pairs quantitative evaluation with qualitative follow-up (sequential explanatory mixed-methods) and uses an inclusive design supported by a digital platform.

Introduction

Preschool years set the foundation for physical, cognitive and behavioral trajectories across childhood. Motor skills develop rapidly between ages five and six, physical fitness levels start to take shape, and early habits around movement, sleep and eating emerge. Interventions delivered in the classroom that weave short, structured bursts of activity—so-called active breaks—into the daily curriculum have shown promise with older children, yet rigorous evidence at the preschool level remains limited. Researchers in Chile have designed the first controlled trial intended to examine whether a curriculum-integrated active break program can simultaneously improve motor competence, health-related physical fitness, learning outcomes and healthy habits in kindergarten-aged children. The trial’s three-arm structure, inclusive design and mixed-methods evaluation aim to answer not only whether the program works, but how dose matters and what facilitates real-world uptake in public school settings.

Why this matters: establishing effective, scalable strategies to increase physical activity in early childhood can influence immediate developmental domains and set children on healthier life courses. This protocol previews a methodologically robust field experiment that addresses gaps in preschool implementation, integrates technology for teacher support, and prioritizes practical relevance for education policy.

Why preschool active breaks deserve serious attention

Motor skill proficiency, cardiorespiratory and muscular fitness, attention and self-regulation all show important developmental changes during the final year of kindergarten. Motor competence is not merely a matter of play; it shapes children’s confidence to engage in movement across contexts and is linked to sustained physical activity through childhood. Early fitness levels correlate with current health markers and predict trajectories that influence long-term cardiovascular and metabolic risk. Classroom-based active breaks offer a pragmatic delivery channel: they sit inside the school day, require limited resources, and can be embedded in learning time so they do not compete with the academic agenda.

Evidence supports classroom activity for older children: short activity bursts improve on-task behavior, attention and some academic outcomes when delivered regularly. For preschoolers, however, evidence is fragmented. Many studies are small, short-term, or focus on single domains (for example, motor skills only). This Chilean trial responds to that gap by testing multiple outcomes concurrently—motor competence, physical fitness, learning measures and health behaviors—under real-world school conditions. A trial that probes dose-response (high vs. moderate frequency) will help answer whether simply introducing activity or increasing its frequency drives measurable benefits at this developmental stage.

Designing active breaks that integrate with the curriculum

An effective classroom active break program for five- and six-year-olds must balance four design constraints: developmental appropriateness, curricular relevance, teacher feasibility, and inclusivity.

• Developmentally appropriate movement. Activities should emphasize gross motor patterns—running, jumping, hopping, throwing, balancing—while layering coordination and rhythmic elements that challenge motor planning. For kindergarteners, sessions of brief, game-like movement with clear visual and auditory cues maintain engagement.
• Curriculum integration. Positioning active breaks as brief learning tools—movement tied to numbers, letters, story elements or scientific concepts—assures teachers that activity reinforces educational goals rather than displaces them. For example, a counting game that combines hopping sequences with numeral recognition or a story-driven chase that reinforces vocabulary weaves motor practice into learning objectives.
• Teacher feasibility. Teachers will implement the program across diverse urban public schools. That requires simple instructions, short session durations, minimal equipment, and a predictable routine. When teachers can select from a bank of structured active break modules and adapt them for space limitations, adherence improves.
• Inclusive design. Children enter kindergarten with wide variation in motor ability, attention, physical capacity and behavior. Activities must have scalable difficulty, offer alternative movement options for children with lower motor skills or physical limitations, and promote participation without stigmatization. Inclusion also means cultural and linguistic relevance in materials and examples.

The Chilean trial’s program was designed to meet these constraints and delivered through a teacher-facing digital platform that provides structured sessions, adaptations, and supporting materials. A digital scaffold helps standardize delivery while allowing flexibility for classrooms with different space or equipment realities.

Trial design: three-arm, cluster-controlled and pragmatic

The study uses a three-arm, non-randomized cluster-controlled design across 12 urban public schools in Biobío province. Schools, not individual children, are the unit of assignment, which reflects the intervention’s schoolwide delivery and reduces contamination risk. The arms:

• Total Experimental Group (TEG): 4 schools, n ≈ 67 children, targeted dose of 10 active breaks per week (approximately two per school day).
• Partial Experimental Group (PEG): 3 schools, n ≈ 66 children, targeted dose of 3–5 active breaks per week (roughly intermittent delivery across days).
• Control Group (CG): 5 schools, n ≈ 67 children, continuing standard classroom routines with no structured active breaks introduced.

The trial spans 16 weeks, with primary and secondary outcome assessments at baseline and immediately post-intervention. The non-randomized allocation likely reflects practical constraints such as school schedules, administrative buy-in or prior commitments; non-random designs are common in school-based research when tightly controlled randomization would undermine feasibility. The study offsets potential baseline imbalances with cluster-level analyses and baseline covariate adjustment.

Sample size and setting: approximately 200 preschoolers across 12 schools provides moderate statistical power for detecting medium-sized effects at the cluster level, especially given the trial’s focus on multiple correlated outcomes. Urban public schools in Biobío provide a relevant context for generalization to other mid-sized urban systems in Latin America and beyond. The research team pairs a quantitative evaluation with qualitative inquiry to illuminate the processes behind observed outcomes and to surface implementation barriers and facilitators.

Measuring what matters: primary and secondary outcomes

The trial targets two primary outcomes: motor competence and health-related physical fitness. Secondary outcomes include learning outcomes and healthy habits—specifically sleep patterns, eating behavior and nutritional status.

Motor competence. Assessment of motor competence in early childhood typically uses standardized, age-appropriate batteries that measure locomotor skills (running, hopping), object control skills (throwing, catching, kicking) and balance/coordination tasks. These measurements capture both proficiency and movement quality. Improvements in motor competence indicate not only physical gains but greater confidence to engage in play and sports, which can catalyze longer-term activity patterns.

Health-related physical fitness. For preschool-aged children, field-based measures appropriate for group testing include tests of cardiorespiratory endurance (short shuttle runs adapted for age), muscular strength/endurance (modified push-ups or handgrip in older children), and flexibility. Body composition and anthropometrics—height, weight, BMI—are standard components for assessing nutritional status and fitness-related risk markers. The trial’s focus on health-related fitness acknowledges that functional capabilities, not only motor skill, influence participation and health trajectories.

Learning outcomes. The trial will evaluate academic and cognitive indicators relevant to kindergarten curricula. Short active breaks have demonstrated acute effects on attention and on-task behavior, which can accumulate into measurable learning gains when sustained. Assessment approaches may include teacher-rated classroom behavior, simple standardized tests of pre-literacy and numeracy, and tasks probing executive function domains like inhibitory control and working memory.

Healthy habits. Sleep and eating behaviors are foundational for both cognitive performance and physical development. The study will assess sleep patterns and eating behaviors via validated questionnaires adapted for parent-report or teacher-report, and will measure nutritional status through standard anthropometry. Because preschoolers’ habits are strongly mediated by family routines and home environments, a mixed-methods approach will be important to contextualize any observed changes.

Timing and measurement protocol. Baseline and post-intervention assessments will capture change over the 16-week period. The mixed-methods design—quantitative follow-up data combined with qualitative interviews or focus groups—will allow researchers to attribute observed changes to program elements and understand contextual moderators like classroom culture, teacher buy-in, space constraints and family support.

Dose matters: comparing high and moderate frequency

A central question this trial addresses is whether the frequency of active breaks drives differential benefits at preschool age. The trial contrasts a high-frequency schedule (approximately 10 breaks per week) with a moderate-frequency one (3–5 breaks per week) and with a control. This design will permit several informative comparisons:

• High vs. control: test whether a robust, consistent active-break schedule yields measurable improvements across motor and fitness domains, and whether these gains translate into better learning outcomes or healthier habits over 16 weeks.
• Moderate vs. control: evaluate whether lower-frequency implementation—more feasible for many classrooms—produces effects that are detectable and educationally meaningful.
• High vs. moderate: inform practical trade-offs. If moderate frequency achieves similar gains to the high dose, schools may prioritize lower-intensity adoption. If the high dose is clearly superior, policymakers and educators will have evidence supporting investment in more consistent implementation.

Dose-response research is rare in early childhood activity interventions. Frequency and intensity, along with session duration and content quality, interact to determine physiological stimulus and skill practice. For motor skill acquisition, repeated practice matters: frequency provides the repetition necessary for neuromotor learning. For fitness improvements, accumulated time in moderate-to-vigorous physical activity matters. The trial’s multi-domain outcome set allows researchers to detect whether different domains respond differently to frequency—for instance, motor competence may require repeated skill-focused movement, while short attention gains might respond to fewer, well-structured breaks.

Digital platform support and inclusive materials

Implementing a standardized active break program at scale demands user-friendly resources. The Chilean trial incorporates a digital platform to support teachers with session plans, demonstration videos, adaptation strategies, and tracking tools. Digital scaffolding addresses common barriers: teachers report time pressure, uncertainty about safe activities or adaptations for diverse learners, and difficulty maintaining novelty to sustain student engagement.

Key functionalities likely included on the platform:

• A library of short active break modules (2–10 minutes), tagged by theme, skill focus and required space/equipment.
• Step-by-step guidance for adaptations for children with lower motor competence or physical limitations.
• Short training modules or demonstrations that model classroom management strategies for active breaks.
• Progress tracking for frequency of sessions at the classroom level, enabling fidelity monitoring.
• Materials for parent outreach to reinforce habits at home, such as simple activity guides that families can use.

Digital tools can standardize exposure while preserving teacher choice. They can also collect implementation data unobtrusively, allowing the research team to correlate dosage with outcomes and to identify patterns in adherence across different school contexts. Importantly, an inclusive design embedded in the platform—offering multiple routes to participation—reduces the risk of excluding children who need modifications.

Mixed-methods sequencing: why QUAN → qual adds value

The trial uses a sequential explanatory mixed-methods design: quantitative evaluation first (QUAN), followed by qualitative inquiry (qual). This sequencing prioritizes measurement of effect size and statistical significance, then uses qualitative data to explain why and how effects occurred or failed to occur.

Advantages of this approach:

• Outcome-driven explanation. If the quantitative data show improvement in motor competence but not in sleep patterns, qualitative interviews with teachers and parents can explain mechanisms—perhaps movement activities reinforced motor skills but did not alter home sleep routines.
• Fidelity and context. Qualitative data illuminate implementation fidelity: Did teachers actually deliver the planned number or intensity of breaks? Were physical spaces used differently? Such details help interpret quantitative findings.
• Acceptability and scalability. Teachers’ perspectives on feasibility, student engagement, and materials usability inform potential scale-up. Focus groups or interviews can surface contextual barriers—timing conflicts with other curricular demands, constraints in play areas, or administrative support needs.
• Tailored improvement. Qualitative insights support iterative refinement of the program and digital platform by highlighting which activities were most engaging, where adaptations were necessary, and how to better integrate breaks with learning objectives.

Taken together, the mixed-methods design converts statistical differences into actionable knowledge about program delivery and real-world adoption.

Anticipated impacts and plausible pathways of effect

The trial hypothesizes benefits across four domains. Mechanistic pathways explain how classroom active breaks may generate those outcomes.

Motor competence. Repeated exposure to structured motor activities provides practice of fundamental movement patterns, promotes motor planning and coordination, and strengthens neural pathways supporting skill execution. Gains in motor competence are expected to arise from the cumulative repetition in both high- and moderate-dose groups, with potentially greater improvements in the high-frequency arm.

Health-related physical fitness. Active breaks that elevate heart rate and engage large muscle groups may increase short-term cardiorespiratory load and contribute to improved endurance measures. However, 16 weeks of brief breaks might yield modest changes in fitness compared with longer-duration exercise programs. Nonetheless, even small improvements in activity-related fitness at this age are meaningful given the developmental window.

Learning outcomes. Active breaks can acutely enhance attention and self-regulation by providing a behavioral reset during the school day. Over weeks, improved attention and classroom engagement may support gains in pre-literacy and numeracy tasks. Furthermore, embedding movement into academic content reinforces learning through multisensory experience.

Healthy habits. Active breaks can normalize movement as part of daily routine, potentially influencing children’s and families’ views on physical activity. If teachers and parents adopt similar practices at home, sleep and eating behaviors might shift indirectly. Nutritional status is less likely to change dramatically over 16 weeks absent explicit dietary interventions, but small shifts in energy expenditure and routine could surface in anthropometric measures in some children.

The trial’s mixed-methods follow-up will clarify which of these pathways are most active in the school context.

Implementation realities: barriers, facilitators and strategies

School-based interventions often encounter predictable implementation challenges. Anticipating and addressing these realities improves fidelity and impact.

Common barriers:

• Time pressure. Teachers face dense curricula and limited flexibility. Framing active breaks as curriculum-compatible—short sessions that reinforce lesson content—reduces perceived competition for time.
• Space constraints. Urban classrooms and schools with limited outdoor areas require activities adaptable to small indoor spaces. The program’s activity bank should include seated or spot-based options that remain active but are space-efficient.
• Teacher confidence. Staff may be unsure about managing movement safely or adapting for children with developmental delays. Focused training, modeling videos, and classroom management tips on the platform reduce anxiety.
• Administrative support. Leadership buy-in is crucial. School administrators who endorse the program create schedule allowances and encourage teacher participation.

Facilitators:

• Low equipment needs. Activities using body weight and common classroom props scale easily.
• Teacher autonomy. Allowing teachers to select modules that match their daily objectives promotes ownership.
• Rapid feedback. Simple fidelity tracking and visible classroom-level progress encourage sustained engagement.
• Family involvement. Materials that encourage parents to reinforce movement at home create a supportive ecosystem.

Strategic recommendations for scale-up:

• Integrate into teacher professional development cycles, not as a one-off training.
• Develop school-level champions who model active breaks and mentor colleagues.
• Provide micro-credentials or recognition for teachers who sustain implementation.
• Offer data dashboards that show classroom-level participation and student-level progress to maintain motivation.

Ethical and equity considerations

Interventions in early childhood must prioritize equity and non-stigmatizing inclusion. The trial’s inclusive design recognizes variation in baseline motor competence and socio-economic factors that shape access to physical activity resources outside school. Ethical considerations include:

• Consent and assent. Parental consent and child assent procedures must ensure understanding and voluntariness.
• Privacy and data protection. Collection of anthropometric and behavioral data requires secure handling, especially when shared across research and school systems.
• Equitable participation. Adaptations must prevent exclusion of children with disabilities or lower motor skills and avoid singling out children for differential treatment.
• Cultural sensitivity. Activity examples, narratives and visual materials should reflect local culture and language to resonate with children and families.

Addressing these concerns strengthens both ethical rigor and the intervention’s acceptability.

How the Chilean context shapes the study and its implications

Conducting the trial in Biobío province’s public urban preschools embeds the study in a real-world education system likely to face resource constraints and diverse classrooms. Results will offer pragmatic insights relevant to other public systems seeking low-cost, curriculum-compatible strategies to increase physical activity in early education.

Policy implications if effective:

• Evidence to inform national early childhood education guidelines that include structured activity time.
• Rationale for investing in teacher resources and digital platforms that support classroom movement.
• Data to support cross-sector collaboration between health and education ministries for early prevention of lifestyle-related risk factors.

If findings show dose-dependent effects, policymakers will have tangible guidance on how frequently active breaks should be integrated to achieve desired outcomes. If qualitative findings reveal manageable scalability barriers, the program could be adapted and piloted across broader regions.

Potential limitations and how the study addresses them

No field trial is without limitations. Anticipated concerns and mitigation strategies include:

• Non-randomized design. Allocation by school rather than random assignment can introduce baseline imbalances. The study counters this with cluster-level analytic techniques and baseline covariate adjustment. Qualitative data may further clarify contextual differences.
• Fidelity variability. Reliance on teacher delivery may produce heterogeneous implementation. The digital platform, teacher training and fidelity monitoring aim to standardize exposure and document variation for analysis.
• Short intervention duration. Sixteen weeks is sufficient to detect motor skill learning and behavioral shifts but may limit detection of larger fitness or anthropometric changes. Findings will identify short-term effects and inform longer-term trials.
• Measurement constraints. Field-based fitness and motor assessments in preschoolers involve noise due to attention variability. Standardized procedures, trained assessors and appropriate age-adjusted tools reduce measurement error.
• Generalizability. Urban public schools in one Chilean province may not represent rural settings or private schools. Nevertheless, findings will be informative for similar public systems and guide adaptation.

Expected contributions to research and practice

This trial advances the field in several ways:

• Multi-domain evaluation. Simultaneously testing motor competence, fitness, learning and habits fills a crucial evidence gap and reflects the interconnected nature of child development.
• Dose-response evidence. Comparing two active-break frequencies will inform how much classroom activity is needed to achieve meaningful effects.
• Implementation science lens. Pairing quantitative outcomes with qualitative process data elucidates pathways and practical constraints that matter for scaling.
• Digital support model. Demonstrating how technology can assist teachers with adaptable, inclusive activity modules provides a replicable approach for resource-limited settings.

Practitioners and policymakers will find actionable findings about what works in preschool classrooms, how to support teachers, and what reasonable expectations are for outcomes across domains.

Bringing active breaks into everyday preschool practice: a practical roadmap

For educators and administrators considering adoption of classroom active breaks, the following steps translate the trial’s insights into practice:

1. Begin small and be consistent. Start with two short breaks per day that align with transition times (after morning tasks, before a focused lesson) to minimize disruption and build routine.
2. Choose activities with learning ties. Pair movement with counting, letter recognition, story sequencing or vocabulary practice to reinforce curriculum goals.
3. Use scalable difficulty. Provide options within each activity for simpler and more complex movement so all children can participate meaningfully.
4. Train and model. Offer short, practical training sessions highlighting classroom management during active breaks and model the activities in live demonstrations or video.
5. Leverage simple tracking. Maintain a visible classroom chart tracking active break frequency to sustain teacher focus and student enthusiasm.
6. Communicate with families. Send brief handouts or videos suggesting two at-home activities that mirror classroom breaks to reinforce habits.
7. Monitor and adapt. Collect brief teacher feedback and observe sessions periodically, adjusting activities to suit classroom space and rhythm.

These steps reflect lessons the trial aims to test and refine. When schools adopt movement as a pedagogical tool rather than an add-on, sustained benefits are likelier.

Real-world examples that illuminate potential outcomes

Several established initiatives offer instructive parallels:

• The Daily Mile: Originating in primary schools, this short daily running/walking break has demonstrated improvements in physical activity levels and classroom engagement in older children. While Daily Mile emphasizes continuous moderate activity, adapting its brevity and routine to preschool settings illustrates how short, consistent activity can normalize movement.
• Classroom “energizers” and academic movement integration: Programs that embed movement into learning activities—songs with action cues for literacy or math games that require physical responses—show improved on-task behavior and enjoyment. For preschoolers, these approaches exemplify how movement can be a teaching strategy as much as a health behavior.
• Teacher-led motor skill curricula: Structured skill-teaching sessions that scaffold locomotor and object-control skills show promise for raising motor competence. When combined with playful, curriculum-linked active breaks, such curricular elements may accelerate skill gains.

These examples underscore feasible models for classroom movement and suggest possible outcomes the Chilean trial may observe in preschool contexts.

Next steps and scaling considerations if results are positive

Positive trial results would provide a platform for broader implementation and further research. Practical next steps include:

• Pilot expansion. Adapt and pilot the intervention in diverse regions (rural, varied socio-economic contexts) to test generalizability.
• Longer-term follow-up. Assess whether early improvements persist into first and second grade and whether early motor competence predicts later physical activity trajectories and academic outcomes.
• Policy translation. Collaborate with education authorities to embed active break guidance into early childhood curricula and teacher training modules.
• Integration with family-based programming. Develop complementary home activity resources and community supports to reinforce school-based gains.
• Economic analysis. Conduct cost-effectiveness studies to inform resource allocation decisions at district or national levels.

Scaling requires investment in teacher support, digital infrastructure, and monitoring systems, but the relatively low-cost nature of active breaks makes broad adoption feasible.

FAQ

Q: What exactly is an "active break" in a preschool classroom? A: Active breaks are brief, structured intervals of movement—typically 2–10 minutes—introduced during the school day. They combine gross motor activity (running, jumping, balancing) with simple coordination tasks and can be linked to curricular content (counting, letters, stories). Sessions are designed to be age-appropriate, inclusive, and feasible in typical classroom spaces.

Q: Why test different frequencies of active breaks? A: Frequency determines the amount of motor practice and accumulated physical activity exposure. Comparing a high-frequency schedule (about 10 breaks/week) with a moderate-frequency one (3–5 breaks/week) clarifies whether more frequent short bursts yield greater benefits in motor competence, fitness and learning—or whether modest doses achieve similar results with less teacher burden.

Q: How will motor competence and fitness be measured in five- to six-year-olds? A: Age-appropriate, standardized assessments measure locomotor skills (running, hopping), object control (throwing, catching), balance and coordination, along with field-based fitness tests adapted for preschoolers. Anthropometric measures capture nutritional status. The trial uses trained assessors and standardized protocols to ensure reliable measurement.

Q: Will the program work for children with developmental delays or disabilities? A: The program's inclusive design emphasizes adaptable activities and scalable difficulty levels so children with diverse motor abilities can participate. The digital platform provides adaptations and guidance for teachers to modify activities safely. Qualitative data from the trial will clarify participation patterns and necessary supports.

Q: Does the trial measure academic learning? A: Yes. Secondary outcomes include learning measures relevant to kindergarten curricula, such as pre-literacy and pre-numeracy tasks, and classroom behavior indicators like attention and on-task behavior. The trial assesses whether physical activity integrated into the school day supports learning gains alongside motor and fitness outcomes.

Q: How does the mixed-methods design strengthen the trial? A: Quantitative assessments establish whether measurable changes occurred; qualitative inquiry then explores how and why those changes happened—or why they did not. This sequential explanatory approach provides insight into implementation challenges, teacher perceptions, and contextual factors that influence outcomes and scalability.

Q: What role does the digital platform play? A: The platform supports teachers with structured session plans, demonstration videos, adaptation strategies for inclusivity, and tools to track implementation. It standardizes delivery, facilitates fidelity monitoring, and supplies resources to integrate active breaks with curricular objectives.

Q: Can schools adopt this approach without the digital platform? A: Yes. Active breaks can be implemented with printed guides and short teacher training. The digital platform enhances standardization, ease of access to varied activities, and monitoring, but the core principles—short, structured, curriculum-linked movement—are replicable with low-tech materials.

Q: How long before schools could expect to see benefits? A: Some benefits, such as improved on-task behavior and immediate attention, can appear acutely after single activity sessions. Motor competence gains and measurable changes in fitness or academic performance may emerge over weeks. The trial’s 16-week timeframe is designed to capture short-to-medium-term effects.

Q: If effective, what are the implications for policy? A: Positive results would support integrating structured active breaks into early childhood education guidance, teacher professional development and school routines. Schools could adopt low-cost, curriculum-compatible movement strategies that promote motor development and support learning and healthy habits at scale.

This trial protocol represents a methodologically rigorous attempt to move beyond pilot studies and single-domain interventions. By embedding active breaks within the curriculum, testing dose effects, using digital supports and combining quantitative outcomes with qualitative explanation, the study aims to produce actionable evidence for educators and policymakers seeking to prioritize movement in the earliest years of schooling. Results will help clarify how brief classroom movement can shape motor skills, fitness, learning and daily habits at a time when children are primed for developmental gains.