Which term describes the neuromuscular phenomenon where an overactive muscle reduces neural drive to its antagonist?

• A. Altered reciprocal inhibition
• B. Upper crossed syndrome
• C. Pronation distortion syndrome
• D. Lower crossed syndrome

Answer: (A)

Reciprocal inhibition is the nervous system’s way of coordinating movement by sending an inhibitory signal to the muscle opposite a contracting one. When a muscle is overactive, this inhibitory signal to its antagonist can become excessive, reducing neural drive to that opposing muscle beyond normal levels. That exaggerated or altered inhibition is what the term “altered reciprocal inhibition” describes. It explains how an overactive muscle can suppress the activity of the muscle opposite it, contributing to a sustained imbalance.

The other terms describe common postural patterns or syndromes (like upper crossed, pronation distortion, and lower crossed), which outline where muscles tend to be tight or weak but aren’t naming the specific neuromuscular mechanism involved in this altered inhibition.