Lines in movement
Every move of an arm, leg or the whole body draws a line. Three kinds are common:
- Straight (vertical): tall, calm, strong.
- Diagonal: slanted, full of energy and surprise.
- Curved: soft, flowing, gentle.
A dancer also draws lines on the floor (the path walked) and in the air (the path of a hand).
Shapes in movement
The whole body can make shapes: a triangle (legs wide, arms up), a circle (arms in a ring), a square (sharp corners at elbows), or a wide X. Groups also make shapes with their positions. Clear shapes help the audience see the idea, even from far away.
Balance and weight: the centre of gravity
Weight pulls everything down. The centre of gravity is the point where all the body weight seems to gather. For a person standing it is near the belly, a little below the navel.
If you raise the arms the point moves a little up. If you bend sideways it moves sideways.
The base and staying balanced
The base is the area between the supporting feet. Rule: the body is balanced when a straight line down from the centre of gravity falls inside the base.
- Wide base: more room, more stable.
- Narrow base or one foot: less room, harder to hold.
- Low centre (bent knees): steadier.
When the line goes outside the base, the body falls. Stretching an arm or leg the other way (counterbalance) moves the point back inside.
Try it: At home, stand on one foot, then lean slowly. Notice how far you can go. Now stretch the other arm and leg out: you can lean more. In the 3D, find the biggest lean that stays safe for the narrow base.
Key formulas and definitions
- Balanced if: centre of gravity line falls inside the base
- Sideways shift of the point = height × sin(lean angle)
- Wider base + lower centre = more stable; counterbalance pulls the point back
Worked examples
1. A dancer has a base 0.6 m wide, so half the width is 0.3 m. The red point is 0.2 m from the centre. Is the dancer balanced?
Yes. 0.2 m is less than 0.3 m, so the point is inside the base.
2. The same dancer leans until the point is 0.4 m from the centre. What happens and what can help?
0.4 m is more than 0.3 m, so the dancer falls. Stretching an arm the other way or widening the feet brings the point back inside.
3. The centre of gravity is 1.2 m high and the lean is 30 degrees (sin 30 = 0.5). How far does the point shift sideways?
1.2 × 0.5 = 0.6 m. The base half-width must be more than 0.6 m to stay up.
Common mistakes
- Thinking the centre of gravity is always in the chest. It is lower, near the belly.
- Standing with feet together and trying to lean far.
- Forgetting that raising a heavy prop changes the balance point.
- Thinking lines are only on the floor. Arms and legs draw lines in the air too.