If there is a deficit in central activation ratio (CAR), voluntary strengthening is typically?

• A. Highly effective
• B. Difficult to overload muscles when you can't effectively activate them
• C. Completely ineffective
• D. Unrelated to AMI

Answer: (B)

When CAR is reduced, the nervous system isn’t able to fully recruit the muscle during voluntary effort. Achieving the high-intensity contractions needed for progressive overload depends on strong voluntary activation, so if activation is limited, pushing load through voluntary work becomes difficult. That’s why voluntary strengthening is typically hard in this situation. In rehab, this deficit is often addressed with strategies like NMES to help recruit more motor units and achieve overload despite limited voluntary activation. The other options don’t fit because the issue isn’t that strengthening is completely ineffective or highly achievable on its own, and this deficit is related to arthrogenic muscle inhibition rather than being unrelated.