Collocations for reflex - noun

good, lightning, quick | poor | automatic | natural | conditioned

trigger
The rapid movement of an object towards the eye triggers the blink reflex.

control | sharpen, speed up
The training is designed to sharpen the fighter''s reflexes.

slow (down)
Alcohol can slow your reflexes.

suppress | test
The doctor tested her reflexes.

action, reaction
Almost as a reflex action, I grab my pen as the phone rings.

by ~
Almost by reflex, he helped himself to a drink.