Effects of Resistive Jaw-Opening Exercise with Elastic Bands on Suprahyoid Muscle Activation in Normal Subjects

Objective: The effect of a resistive jaw-opening exercise using an elastic band on suprahyoid muscle activity and tongue strength was examined in healthy volunteers. Methods: Twenty-one adults wore an elastic loop around their head and mandible. To prescribe the appropriate elastic band resistance, the 10-repetition maximum (10 RM) was measured among 4 bands at baseline. Band loops, starting with the highest resistance value band, were sequentially applied to determine the suitability for 10 RM. During the exercise, the participants were required to open their jaw maximally and maintain the position for 10 s; then, they rested for 10 s. This procedure was repeated for 20 min, 3 days per week for 8 weeks to test suprahyoid muscle activation during effortful swallowing; isometric tongue pressures of the tongue tip and base at baseline, after 4, and after 8 weeks of training were measured. Results: Peak suprahyoid muscle activation amplitudes during effortful swallow and isometric pressures at the tongue tip significantly increased after 8 weeks. Conclusion: The 8-week resistive jaw-opening exercise significantly improved strength of the suprahyoid muscle and tongue pressures in healthy subjects. These positive results warrant further investigation of the therapeutic effects and feasibility of this resistive exercise.