Effects of Tongue-Strengthening Exercise on Tongue Strength Reserve and Detraining Effects among Healthy Adults: A Randomized Controlled Trial

Introduction: Tongue strength reserve is the difference between the maximum isometric pressure (MIP) and swallowing pressure of the tongue. People with decreased tongue strength reserve may have a higher risk of presbyphagia or dysphagia. Thus, this study explored the effects of tongue strengthening exercise (TSE) on tongue strength reserve and detraining effects in healthy adults. Materials and Methods: In total, 102 healthy volunteers without any reported history of speech or swallowing deficits were recruited and assigned to experimental (n = 50) and control groups (n = 52). Exercises in the experimental group consisted of compressing an air-filled bulb between the tongue and hard palate for 30 min a day, 5 days a week, for 8 weeks. Thereafter, the experimental group underwent a 4-week detraining period. Results: Following the TSE training, posterior tongue strength reserve (F = 4.92, p = 0.029) of the experimental group was significantly higher than that of the control group. No significant detraining effects were observed on the MIP and swallowing pressure from 4 weeks after the completion of TSE training. Conclusions: According to the study results, TSE may be an effective approach for improving swallowing function.