Which action constitutes reinforcement to increase reflex activity?

• A. Raise the legs and stomp
• B. Clench teeth and lock fingers
• C. Sip water slowly
• D. Close the eyes

Answer: (B)

Reinforcement during reflex testing aims to boost reflex activity by increasing motor neuron excitability through concurrent effort and heightened CNS arousal. The classic maneuver for this is clenching the teeth while locking the fingers and pulling apart, which is why this action best increases the reflex response. This brief, voluntary simultaneous contraction elsewhere raises cortical and brainstem drive to the reflex arc and reduces inhibitory influences on the Ia fibers reaching the motor neurons, making the reflex more pronounced. The other actions don’t employ this facilitation mechanism: raising the legs and stomping isn’t a standardized reinforcement, sipping water slowly isn’t about enhancing reflex excitability, and closing the eyes doesn’t actively increase reflex responsiveness.