Children Who Moved More at Preschool Gained Vocabulary

But the amount of movement did not explain the change — the puzzle left by a randomized trial of 314 children

Introduction: The Fuzzy Part of “Run Around and Get Smarter”

Nobody disputes that moving a lot is good for children. Fitness, sleep, mood, obesity prevention — the evidence is plentiful.

One more claim gets stacked on top: exercise is good for the developing brain. There is research behind it. In particular, reports have accumulated that executive function — planning, sustaining attention, inhibiting impulses, switching as the situation demands — improves with physical activity. Executive function develops rapidly between ages 3 and 5 and is known to predict school readiness better than IQ.

But that evidence has two gaps.

One is age. Most existing studies used school-age children. Evidence from early childhood, when executive function grows fastest, is far thinner.

The other is more fundamental. Does exercise work because of the exercise? Whether raising the heart rate by running is what changes the brain, or whether something else that comes bundled with physical activity is doing the work — few studies have separated the two.

A team from Deakin University and the University of Canberra in Australia took on the question across 15 preschools. And on the second question, the answer was unexpected.

The Core Question

The team’s question comes in two stages.

“Does a program that increases physical activity within the preschool day improve young children’s executive function and language development?”

And then, once the results were in:

“If it improved them, was it because physical activity increased?”

How They Studied It: 22 Weeks, Randomized by Preschool

The Design

A cluster randomized controlled trial. Assignment was by center, not by individual child, to avoid a situation where some children within one center got the program and others did not.

• Sites: 15 Australian preschools
• Children: 314 aged 3–5 (134 girls)
• Assignment: 8 centers / 170 children treatment, 7 centers / 144 children control
• Start: May 2019
• Method: stratified by center socioeconomic level, national quality rating, and region, then randomized by computer by an independent researcher
• Retention: at 6 months, 75% treatment, 76% control

What They Did

The Active Early Learning (AEL) program ran for 22 weeks. Its distinguishing feature is that it did not create a separate PE class; it dissolved movement into the existing preschool day.

Four components were introduced sequentially over four weeks each, then integrated.

1. Group time and transitions — putting movement into the still moments
2. Movement education — teaching fundamental movement skills
3. Curriculum-integrated movement activities — combining physical movement with other learning activities
4. Encouraging challenging free play — encouraging children to challenge themselves physically

The delivery model is interesting. Specialist instructors did not teach the children; a peer coach visited each preschool weekly to support the teachers. They demonstrated activities, supplied materials, helped integrate them into the curriculum, and checked on progress. Of 176 planned visits, 164 (93%) actually took place.

Because teachers preferred them over digital tools, materials came as laminated activity cards.

The control group ran as usual.

What They Measured

Executive function — three tablet-based tasks from the Early Years Toolbox

• Inhibition: a Go/No-Go task. Tap the screen when a fish appears; hold back when a shark appears. 75 stimuli across 3 blocks
• Working memory: a Mr. Ant variant. Remember where stickers sat on the ant’s body and point them out again. Difficulty rises until failure
• Shifting: a card-sorting task. Sort by color at first, then switch mid-task to sorting by shape

Expressive vocabulary — naming 45 pictures

Physical activity — an ActiGraph GT3X+ accelerometer worn at the waist, measured for 3 consecutive days while at preschool. Steps per hour, total activity minutes per hour, moderate-to-vigorous activity (MVPA) minutes per hour

Result 1: Two Things Improved

Inhibition and expressive vocabulary improved significantly. Inhibition is the power to hold back an impulse; expressive vocabulary is how many words the child can produce.

Shifting had an effect size of 0.26, comparable to inhibition, but failed to clear the statistical bar (p = .084). That belongs in the “there was a tendency but it cannot be confirmed” category. Working memory showed essentially no change.

That vocabulary grew out of a physical activity program is the most unexpected part, because this was not an intervention aimed at language.

Result 2: The Control Group Actually Moved Less

The physical activity data makes the character of this trial look somewhat different.

Treatment (per hour)

• Total activity: 17.51 min → 17.95 min
• Moderate-to-vigorous activity: 9.15 min → 9.44 min

Control (per hour)

• Total activity: 18.27 min → 14.25 min
• Moderate-to-vigorous activity: 9.58 min → 7.34 min

The treatment group barely changed; the control group fell noticeably. At baseline the control group was in fact slightly more active.

So what the program did was less “make the children move more” than hold on to activity that naturally declines over time. That has value of its own, but it is a fact to weigh when reading the results.

Result 3: But Movement Didn’t Explain the Effect

This is the most interesting point in the study.

The team ran a mediation analysis — the procedure for checking whether the increase in physical activity explains the improvements in executive function and vocabulary. The logic is simple. If exercise is what helped, children who moved more should have improved more.

No such relationship appeared.

There was no significant relationship between total activity or MVPA and any executive function domain, or vocabulary (all p > .1). The team’s phrasing:

No evidence emerged that physical activity played a mediating role in any of the relationships.

The program worked. And the effect was not explained by how much the children moved.

So What Changed the Children

The team offers four possibilities.

1. The Thinking That Came With the Movement

AEL activities were not simply running. Many involved learning new movement skills, responding to cue words, following rules. Such activities demand focus, problem solving, and response inhibition.

That inhibition improved selectively fits this reading especially well. The children got better at the task requiring them to hold back when a shark appears — and in the program they were continually practicing stopping and switching their movement on a cue.

2. Social-Emotional Change

Teacher–child interaction may have improved. Stress may have fallen and enjoyment risen. The vocabulary gain has room to be explained by this route: as physical activity increased, so may have the words exchanged between teacher and child.

3. Activity the Accelerometer Missed

This is both a measurement limitation and an important clue. Balancing, climbing, throwing and catching a ball do not move the whole body much and register poorly on an accelerometer. If those were the activities producing the effect, the instrument may have missed them.

4. Challenging Play

Related to the program’s fourth component, challenging free play. Research links play in which children gauge risk for themselves to planning, focus, and inhibition.

Why Not Working Memory

The team’s view is that duration, repetition, and intensity fell short. Twenty-two weeks may have been enough to move inhibition but not enough to train working memory.

Practical Takeaways

This Study Does Not Support “Make Them Run More and They’ll Get Smarter”

The most important passage. In this trial, cognitive improvement was not connected to the amount of movement. No grounds emerge here for the claim that keeping a child running longer builds executive function.

What likely worked was movement that demanded thinking — stopping on a cue, learning a new motion, regulating the body inside a rule. The same thirty minutes may differ depending on whether it is undirected running or a game of red light, green light.

It Doesn’t Have to Be a Separate PE Class

This program created no new class. It slipped movement into group time, transitions, and existing learning activities. And it did not teach the children directly — it supported the teachers.

A structure worth borrowing at centers short on time and staff.

Activity Declines If You Leave It Alone

That the control group’s activity fell from 18 minutes per hour to 14 in six months is information in itself. Left alone, it does not hold steady; it drops. Even maintenance may require intervention.

Limitations

The team’s stated limitations:

• Six months may be short. A longer period might have produced effects in other domains, or shown whether the effects persist.
• The accelerometer may have missed the key activity. Stationary activities like balancing, climbing, and throwing and catching went unmeasured. Whether physical activity failed to mediate because movement really is irrelevant, or because the instrument couldn’t see it, cannot be distinguished.
• The relationship between motor skill and executive function was not analyzed. The program taught movement skills, but how gains in those skills connect to cognition was not examined.
• The design was pragmatic and curriculum-integrated, so it may not transfer directly to a standalone physical activity program.
• The sample was skewed. 85% of participating children were Australian-born, mean age 4, in areas of higher socioeconomic status than the national average. Hard to generalize to other countries or lower-income areas.
• 20% of socioeconomic data was missing, constraining demographic analysis.

One thing to add. Effect sizes of 0.24–0.29 are small to moderate for an educational intervention. Hard to call a large change.

Closing Thoughts

The sentence this study leaves twists the conventional wisdom slightly.

A program of physical movement improved children’s inhibition and vocabulary. But the change was not explained by how much they moved.

Talk about exercise being good for the brain is usually delivered in the language of quantity. So many minutes a day, so many times a week. This study puts a question mark on that frame. What changed the children may not have been time spent running but the moments of stopping, regulating, and learning something new contained inside that movement.

If so, what a child needs is not more exercise time but time in which using the body and thinking happen at once.

Source: Olive, L. S., Telford, R. M., Westrupp, E., & Telford, R. D. (2024). Physical activity intervention improves executive function and language development during early childhood: The Active Early Learning cluster randomized controlled trial. Child Development, 95(2), 544–558. https://doi.org/10.1111/cdev.14014