In traditional clicking, your brain sends isolated nerve impulses to the flexor digitorum muscle to contract and release your finger.
In contrast, jitter clicking creates a voluntary isometric co-contraction of both the agonist and antagonist muscles in your forearm and wrist. By tensing your arm into a controlled high-frequency tremor (similar to shivering in cold weather), your index finger vibrates against the mouse switch at 10 to 14+ clicks per second.