Following 8 weeks of bilateral hypoglossal nerve stimulation (Stimulation Group) compared to the no-stimulation Control Group, (A) tongue muscle contraction times were significantly longer, (b) half decay times were longer, and (c) fatigue index was greater, indicating less muscle fatigue. The fatigue index was calculated by constructing a ratio of the average tetanic tension (g) at the end of 2 minutes of stimulation relative to the initial tetanic tension (g), and multiplying by 100 to express the value as the percentage of initial tension.