B. Active Living / C. Movement Competence · Active Living and Movement: Motivated, Fit, Safe and Skilful

Balance Science: Base of Support, Centre of Gravity and Smooth Transitions

C1 A1.5 A1.3About 35 minutes

Learning goals

I can explain how a wider base and a lower centre of gravity make a balance steadier.
I can hold balances on different body parts and at different levels.
I can move smoothly from one balance to another, such as from a one-leg stand to a tripod stand (or an easier version).
I can create and perform a balance sequence with smooth transitions.

Words to know

base of support
The body parts touching the ground and the space between them. Your balance stands on it.

centre of gravity
The point where your body's weight is centred. Usually near your belly button when you stand.

stable
Steady and hard to knock over.

transition
The way you move from one balance or position to the next.

tripod stand
A balance on your two hands and the front-top of your head, which make a triangle, with your knees resting on your elbows.

core
The muscles around your belly and back that help hold your body steady.

Remember from Grade 3

In Grade 3 you held balances on different body parts, in different shapes and at different levels, and moved slowly and with control from one balance to another.

This year you will learn the science of balance: why some balances are steady and some are wobbly. Then you will use it to make your transitions smoother, including moving from a one-leg stand to a tripod stand.

Two secrets of balance

1. Base of support. Your base of support is the body parts touching the ground, plus the space between them.

A wide base (feet apart, or hands and knees) is more stable.
A small base (one foot, or tiptoes) is harder to hold.

2. Centre of gravity. Your centre of gravity is the point where your weight is centred. When you stand, it is around your belly button.

A low centre of gravity (bent knees, crouching) is more stable.
A high centre of gravity (arms up, on tiptoes) is harder to hold.
You stay balanced when your centre of gravity is over your base of support. If it moves outside the base, you tip!

Left: feet wide apart and a lower centre of gravity (the dot) above the base make a steady balance. Right: one foot and a higher centre of gravity make a wobbly balance.

Balances to try

Try each one for 5 seconds. Then make it harder (smaller base, higher centre of gravity) or easier (wider base, lower centre of gravity).

Balance	Base of support	Level
One-leg stand (stork)	One foot	High
Front support (plank)	Two hands and two feet	Low
Side support	One hand and the side of one foot	Low to medium
V-sit	Your seat (bottom)	Low
Arabesque (scale)	One foot, with your body leaning forward and the other leg reaching back	Medium
Three-point kneel	Two hands and forehead on the mat, knees on the floor	Low
Tripod stand	Two hands and the front-top of your head, in a triangle	Low

Some Grade 4 balances. Notice the base of support for each one.

Seen from above: the wider the base of support, the steadier the balance. The tripod stand uses a triangle of two hands and the head.

Smooth transitions

A transition joins one balance to the next. A smooth transition is:

slow and controlled, not a fall or a flop,
planned, so you know which body part goes down first,
done by lowering your centre of gravity gently and moving your base one part at a time.

Use your core (belly and back muscles) to stay tight and steady. Keep your eyes on one spot.

Safety for balancing

Balance on a soft surface like a gym mat or carpet, with space all around you.
Bare feet or running shoes; no socks on smooth floors.
For the tripod stand, work on a mat with a grown-up spotting beside you. Most of your weight goes on your hands, not your head. Come down by lowering your knees. If your neck hurts, stop. Doing the three-point kneel instead is a great choice.
Never balance on top of furniture.

Worked example

Let's build a smooth transition: one-leg stand to tripod stand

Move from a one-leg stand to a tripod stand slowly and with control.

Start: one-leg stand. Arms out, eyes on a spot, core tight. Hold for 3 seconds.
Lower your centre of gravity: bend your standing knee slowly and reach both hands toward the mat in front of you.
Widen your base: place both hands on the mat, shoulder-width apart. Put your lifted foot down. Now your base is two hands and two feet.
Make the triangle: place the front-top of your head on the mat in front of your hands, so your hands and head make a triangle.
Climb up: walk your feet in. Place one knee on the outside of one elbow, then the other knee on the other elbow. Hold for 3 seconds.
Not ready for the tripod? Stop at the three-point kneel (hands and forehead down, knees on the floor). That is still a smooth transition.

A smooth transition lowers the centre of gravity and widens the base one step at a time, so you never flop or fall.

Worked example

Let's fix a wobbly balance

Jonah tries an arabesque (scale). He wobbles and falls every time. His arms are down, he is looking at his feet, and his standing knee is locked straight. What can he change?

Eyes: look at one spot ahead, not at his feet.
Arms: reach his arms out to the sides. They help keep his centre of gravity over his foot.
Knee: keep a tiny bend in his standing knee, not locked.
Core: squeeze his belly muscles to stay tight.
Make it easier first: hold the back of a chair with one hand (a grown-up keeps it steady), then let go.

With eyes on a spot, arms out, a soft knee and a tight core, his centre of gravity stays over his base, so he can hold the balance.

Hands-on activity

Balance sequence challenge

You need: a soft surface (carpet, yoga mat or grass), a timer and a grown-up as spotter.

Test the science: stand on two feet wide apart, then feet together, then one foot, then one foot on tiptoe with arms up. Which was easiest? Which was hardest? Why?
Choose 3 balances from the table at different levels (one high, one medium, one low).
Plan transitions between them. Write which body part goes down or comes up first.
Perform your sequence: hold each balance for 3 seconds, and make each transition slow and smooth.
Perform it for your grown-up. Ask them to look for: still balances, smooth transitions and a tight core.
Change one thing to make it better and perform it again.

Safety: Keep a clear space. Only try the tripod stand on a mat with a grown-up beside you; the three-point kneel is a great choice too.

Just for fun

Funny but true: flamingos often stand on one leg, and they can even sleep that way. Now that's a stork stand champion!

Your turn

What is a base of support?

Which is more stable: feet together or feet wide apart?

Where is your centre of gravity when you stand?

Why is a crouch steadier than standing on tiptoes?

What makes a transition smooth?

What body parts make the triangle in a tripod stand?

Do it and check: Move from a one-leg stand to a front support (plank) in 4 slow counts.

More practice: warm-up

Is a one-leg stand a high, medium or low balance?

Should you look at your feet or at one spot ahead when balancing?

Name a balance with a base of two hands and two feet.

True or false: a smaller base makes a balance easier.

What muscles help hold your body steady in a balance?

More practice: on your own

Make a one-leg stand harder in two ways. Use the balance secrets to explain.

A hockey player bends their knees and keeps their feet apart when someone tries to bump them. Why?

Plan a transition from a V-sit to a front support.

Why do your arms help you balance on one foot?

Your tripod stand keeps tipping forward. What might be wrong?

Challenge

Explain, using base of support and centre of gravity, why it is hard to stand on a moving bus without holding on, and what helps.

Create a 4-balance sequence with at least one high, one medium and one low balance, and describe each transition.

With a partner, you hold hands, lean back and balance each other (a counterbalance). Why does it only work if you both lean back the same amount?

Check your understanding

Quiz

Which balance has the widest base of support?

A lower centre of gravity makes a balance...

In a tripod stand, what makes the triangle?

What makes a transition smooth?

You tip over when your centre of gravity moves...

Where should you look when you hold a one-leg balance?

For parents and teachers

Big idea: Grade 4 students perform movement skills that require stability, including smooth transitions from one balance to another using different body parts (the curriculum gives the example of moving from a one-leg stand to a tripod stand). This lesson adds the movement principles of base of support and centre of gravity so children understand why some balances are steadier and how to control transitions.

How to help at home:

Clear a carpeted space and be a spotter. Kneel beside your child for the tripod stand, ready to steady their hips.
Ask "How can you make that balance easier? Harder?" and listen for base and centre of gravity.
Point out balance science in daily life: bending knees on a bus, wide stance in skating.

Common difficulties:

Flopping between balances. Slow it down: count 4 for each transition.
Looking down. Pick a spot on the wall at eye level.
Tripod stand. Children often put too much weight on the head or place the head in line with the hands. The head goes in front so hands and head make a triangle, and the hands do most of the work.

Safety: Use a soft surface with clear space. The tripod stand should be attempted only on a mat with an adult spotting; the three-point kneel is an excellent alternative, and any child with a neck or back concern should skip head balances. Never balance on furniture.

Social-emotional learning: Trying a balance, wobbling and trying again builds perseverance; knowing which balances suit your body and choosing a just-right version builds self-awareness.