The "common wisdom" is that, without inertial dampeners, the crew would be literally pasted.
If that's so, then, since the crew is only
getting tossed around during combat, and/or having to climb up to their consoles, the inertial dampeners are—relatively speaking—only very slightly out of adjustment at those times.
Perhaps that's due to fluctuations in the ship's main power systems, like the ones that are blowing up the consoles all the time. Perhaps also there's a slight time lag in dampener reaction during combat, because the application of force on the ship by enemy weapons isn't precisely predicted and accounted for in advance, unlike the programmed acceleration of the ship when executing maneuvers under helm control under normal circumstances.