The Genioglossus (GG), which makes up most of the body of the tongue, is the major muscle responsible for protruding the tongue and is the major UA dilator that opposes collapsing force in the pharynx upon inspiration. Reduced UA dilator force in sleep is posited to contribute to the collapse of the pharynx in OSA (Schwartz 2001). A number of controlled studies have demonstrated that strengthening the GG can result in clinically significant reductions of OSA severity.