Which statement correctly differentiates anticipatory postural adjustments from reflexive balance corrections?

• A. APAs are pre-activation before a known perturbation
• B. APAs occur after perturbation onset
• C. Reflexive corrections are automatic responses before perturbation onset
• D. Reflexive corrections involve only the trunk

Answer: (A)

Anticipatory postural adjustments are pre-activation of postural muscles before a known perturbation. This feedforward preparation anticipates the destabilizing forces of the upcoming movement, helping to keep the body's center of mass within the base of support before the disturbance begins. Reflexive balance corrections, by contrast, occur after the perturbation has started and rely on sensory feedback to generate rapid, automatic muscle responses. They are not pre-activation and can involve coordination across the legs and trunk, not just the trunk. So, pre-activation before the known perturbation best captures the distinction.