fast twitch
They will tire.
The smooth muscles are moving during shivering.
When muscles contract and relax rapidly it is usually called twitching, or fasciculation. It is usually harmless and sometimes caused by a reflex action through the spinal cord, or from an imbalance in electrolytes in the blood, or even excess calcium inside the muscle cells. Rarely it is caused by a neurological problem. So unless it is constant and severe, it is more likely nothing to worry about.
Try Big Bang Theory. Universe started as a big explosion, which expandd rapidly etc
rapidly
more rapidly and most rapidly
more rapidly, most rapidly
more rapidly
more rapidly
He rapidly drove through the puddle.The police arrived rapidly.
The whirlpool spun rapidly.