Comparison of three exercises on increasing tongue strength in healthy young adults

•Isometric tongue exercise increases tongue strength.•Effortful swallow and chin-down swallow exercises also increase lingual strength.•There is no difference in strength increment among the three exercises. To compare three different exercises for dysphagia to see if they had effects on tongue strength. Thirty-one healthy volunteers were randomly divided into three groups. One group (G1, n = 10) performed 24 sets of five repetitions with 30 s rest with the target level set at 80 % of one repetition maximum using Iowa Oral Performance Instrument (IOPI) per day. Another group (G2, n = 10) performed exercise which was consisted of forceful swallow of 5 mL of water in a neutral posture every 10 s for 20 min per day. The other group (G3, n = 11) performed 5 mL of water swallowing exercise in chin-down posture every 10 s for 20 min per day. A total of 12 sessions in four weeks were performed in all groups. Blinded lingual strength measures (maximal isometric pressure) were obtained using IOPI before training and at four weeks after training for the three groups. After four weeks of training, measures of tongue strength were increased significantly in all groups. However, there was no significant difference in strength increment among groups [average increase in strength ± standard deviation (% of initial value): G1, 10.3 ± 10.4 %; G2, 8.7 ± 9.45 %; G3, 9.9 ± 12.6 %, p = 0.825]. Regardless of the type, tongue strengthening exercises had good effects in improving the swallowing function with equal superiority.