Knockback with limited movement

So a commonly asked question is how to limit a rigidbody's speed when using addForce. The common answer is something like:

 if (rigidbody.velocity.maginitude > maxSpeed)
     rigidbody.velocity = rigidbody.velocity.normalized * maxSpeed

But what if the rigidbody is also being hit with external forces like an explosion that doubles the max velocity? As soon as the player moves again the velocity will be set to the max. Is there a way to have both knockback and a movement speed limit?