2.3.3. Measurements of Tongue Muscle Strength
TONGUE, CONTRACTION
Tongue muscle strength was measured using a tongue strength meter (Takei Scientific Instruments Co. Ltd., Niigata, Japan). The maximum tongue muscle strength produced by pushing the tongue depressor was measured using isometric contraction for 3 s. The highest value was considered the maximum tongue strength. A ramp-up task for progressive muscle power exertion was performed against the maximum voluntary contraction (MVC) obtained during tongue raising. The examinee progressively increased the muscle strength at 10% MVC/s from 0% to 80% MVC while receiving visual feedback of the tongue muscle strength data displayed on the monitor. The HD-sEMG was recorded during this task in accordance with the ramp-up task [