Suprahyoid Muscle Activity and Fatigue During Tongue Elevation Compared With the Head Lift Exercise: A Surface EMG...

Strengthening the suprahyoid muscles is fundamental for effective swallowing rehabilitation. Although the head lift exercise is widely employed, it can prove challenging for certain patients. Tongue elevation against the hard palate has been proposed as a feasible alternative. However, its fatigue profile remains underexplored.

To compare suprahyoid muscle activity and fatigue characteristics during tongue elevation against resistance and the head lift exercise using surface electromyography (sEMG).

Eighteen healthy adults performed the head lift exercise and maximal isometric tongue elevation task, each sustained for 20 s. Suprahyoid muscle activity was recorded via sEMG and expressed as normalised root mean square (%RMS) and integrated electromyography (%IEMG). Fatigue was assessed using mean frequency (MNF) and median frequency (MDF) and their linear regression slopes over time. Anterior tongue pressure during tongue elevation was measured with a tongue pressure sensor sheet system.

No significant differences emerged between exercises in %RMS or %IEMG. Both tasks exhibited progressive declines in MNF and MDF. Although MNF slopes did not differ significantly, the MDF slope was significantly steeper during tongue elevation than during the head lift exercise (p < 0.05), indicating greater fatigue. Maximum tongue pressure was higher at the anterior midline than at the posterior peripheral region.

Tongue elevation may be a feasible alternative or adjunct to the head lift exercise for suprahyoid muscle training, particularly for patients unable to perform the latter task. However, this finding should be interpreted cautiously, given the exploratory design and small sample size of the present study.