History and principles of exercise-based therapy: how they inform our current treatment.

Exercises designed to strengthen muscles involved in respiration, phonation, and articulation play a key role in the remediation of voice and swallowing disorders. This article presents exercise physiology principles that are beginning to be used by a small group of speech and swallowing researchers to undergird their efficacy-based studies of exercise-based therapy. Three principles--contraction type, task specificity, and overload--are used to compare past exercise-based therapies with present therapies. Comparisons are made between today's methods and Oskar Guttmann's (1893) principles for strengthening muscles of respiration, Emil Froeschels' (1944) therapy to improve laryngeal function, and the myofunctional therapy of the 1960s to improve swallowing and articulation.