Under which perturbation characteristics is stepping strategy more likely to be used?

• A. Large perturbations, rapid balance loss, or constrained base of support
• B. Small perturbations with wide base
• C. Only sitting tasks
• D. Mild perturbations with stable base

Answer: (A)

Stepping strategy is used when the body needs to create a new base of support to regain stability. It is most likely with large perturbations that push the center of mass toward the edge of the current base of support, or when balance is lost rapidly and there isn’t time for smaller adjustments. A constrained base of support makes stepping necessary because the feet can’t shift enough within the current stance to keep the center of mass over the support area. By taking a step, you rapidly enlarge the base of support and reposition the feet so the body can realign over it and stop the fall. In contrast, small perturbations with a wide base are typically managed by ankle and hip strategies, sitting tasks don’t involve standing balance to step from, and mild perturbations with a stable base can be handled without stepping.