ABSTRACT Purpose: To compare the impact of isokinetic exercise (tongue suction on the palate) in the cervical region of Class I and Class II / 2nd Division participants, considering the average and the symmetry of Root Means Square (RMS) of suprahyoid and suboccipital muscles and cervical sensory reports. Method: 11 participants Class I and 19 Class II / 2nd Division, both genders, mean age 33.4 ± 14.1 years. For the analysis of RMS average and symmetry, electromyography was performed in the suboccipital and suprahyoid muscles, bilaterally, at rest and suction of water in the initial, intermediate and final phases. The cervical sensation was evaluated qualitatively during the exercises. Results: the mean RMS did not differ between Classes (p=0.7), but showed an increase in the intermediate phase in the suboccipital musculature (p=0.0001) and decrease in the suprahyoid musculature. In symmetry, the suprahyoid musculature showed a significant difference between classes (p=0.0001) during the intermediate phase. In the Class I participant the symmetry was reestablished in the final phase, a fact that did not occur in Class II / 2nd Division. Regarding the cervical sensation, only the Class II / 2nd Division had expressive complaints. Conclusion: The Isokinetic suctioning exercise of the tongue against the palate, had an expressive repercussion with reports of discomfort and neck pain in the Class II / 2nd Division participants. On average RMS, there was no difference between the classes, but in the intermediate phase, the suboccipital muscles showed a significant increase in the activity. Symmetry in the suprahyoid musculature had a significant difference between the classes and asymmetry in the intermediate phase.