Plumb Line and Base of Support: Will the Pose Fall?

Using a rope with a weight as a plumb line, students check where their center of gravity falls in different solo and partner balances. Before each pose they predict whether it will be stable and then test it, learning to widen the base and lower the center of gravity.

How to play

1. Explain center of gravity, base of support and line of gravity; build a plumb line with the class using a rope and a tied-on sneaker (4 min).
2. In groups of three, one student holds five positions (standing, on one foot, toe touch, airplane and squat), another hangs the plumb line from the navel and the third takes a photo (8 min).
3. Check in the photos whether the line falls inside the base and note how the body compensates to avoid falling, such as the hips shifting back when leaning forward (4 min).
4. Prediction challenges: the teacher shows six partner balances on mats; each trio bets stable or unstable before trying them (8 min).
5. Each trio invents a pose that looks impossible but whose line of gravity stays inside the base, then shows and explains it (6 min).

Rules

• Partner poses are always done on a mat with a third student as spotter.
• Nobody stands on a partner's lower back: only support on hips and shoulders.
• If a pose isn't stable after 3 seconds, come out of it with control.
• Photos are deleted at the end of class.

Variations

Adaptations

• Limited mobility: analyze the center of gravity while seated by leaning in different directions, and act as spotter in partner poses.
• Autism: get the list of positions with pictures and keep the same trio and mat for the whole class.
• Higher body weight: choose poses with a wide base and act as the base, a role where stability is an advantage.

Learning goals

• Understand how center of gravity, base of support and stability are related.
• Predict and test the stability of positions and poses.
• Apply these principles to create safe poses for body expression.

Equipment for a class of 25

• ropes: 9
• mats: 9
• worksheets: 9
• tablets or phones: 9

Teacher tip

The sneaker plumb line works surprisingly well; have students hold it at navel height, which is a good enough estimate of the center of gravity when standing.

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