Most rockets generally throttle back when they reach max-q to prevent structural failure. This could be the only throttleback event of the launch.
But crewed rockets normally do a second throttleback when acceleration hits 3g to prevent harm to the astronauts on board. The human body doesn't like super high accelerations, and 3g seems to be a common upper limit.
My question: How much do crewed rockets throttle back when they hit that 3g limit? What does the throttle profile look like, and how do the achieve it? Does the throttle program linearly scale back from full throttle in proportion to acceleration above some threshold?
I know it can't possibly just drop suddenly from full throttle to minimum throttle because it would show as a dramatic drop in the acceleration profile, and what I've seen in STS acceleration plots is that acceleration hovers near its upper limit once it hits it. This means the throttleback needs to be smooth and gradual. It needs to be just enough to keep acceleration from going up while also keeping it from going down.
EDIT: Below is a space shuttle launch acceleration profile I found on the web. Notice that region F is at constant peak acceleration. This can only be accomplished by careful throttleback. Acceleration seems to hop up and down about some mean value, which suggests to me they used a deadband within which throttle was to stay constant, something useful if chatter is a concern---but this is guesswork.