During what types of activities do you observe ankle strategies?

• A. Large perturbations
• B. Steady state, small perturbations
• C. No perturbations
• D. Dynamic, unpredictable tasks

Answer: (B)

The key idea is that small, steady disturbances in quiet or steady-state standing are handled by ankle strategies. When sway is gentle, the body behaves like an inverted pendulum anchored at the ankles, so the muscles around the ankle generate torques to shift the center of pressure and rotate the body slightly about the ankle joint. This keeps the center of mass over the base of support with minimal joint movement and without needing hip or stepping actions.

If perturbations are large or faster, the ankle alone isn’t enough, and the system recruits hip strategies or even steps to widen the base and regain stability. No perturbations would require no corrective strategy at all, and dynamic, unpredictable tasks tend to demand more proximal (hip) or stepping responses due to the higher demands on balance control.

Thus, steady-state, small perturbations are where ankle strategies are most observable.