Arndt-Schultz principle

(arnt′shoolts′)

[Rudolf Arndt, Ger. psychiatrist, 1835-1900; Hugo Paul Friedrich Schultz, Ger. pharmacologist, 1853-1932]
The rule that therapeutically applied energy (e.g., thermal agents, ultrasonic energy) must be of the proper intensity per unit of time to stimulate the desired physiological response.