What are the two broad categories of strategies to recover balance?

• A. Ankle strategy and stepping strategy
• B. Fixed support strategies and changing strategies
• C. Steady state and perturbation-based strategies
• D. Fixed support and change in support

Answer: (D)

Balance recovery is defined by how you respond to perturbations relative to your base of support. The two broad groups are fixed-support strategies, where you keep your feet in place and generate corrective torques through the joints you have at the ankle and hip, and change-in-support strategies, where you alter the base of support itself—by stepping or grabbing/supporting with the hands—to reestablish stability.

Within fixed-support, small disturbances are managed mainly by the ankle strategy, which shifts the center of pressure under the feet, and larger disturbances recruit the hip strategy to rotate the trunk and reposition the center of mass while the feet stay planted. When a perturbation is too large to manage without changing the base of support, you use a change-in-support approach—stepping to widen the support base or reaching for a handrail to stop the fall.

This dichotomy—keeping the feet fixed versus altering the base of support—captures the fundamental ways the nervous system restores balance after a disturbance.