Influence of craniocervical motion restriction on cervical and masticatory muscle EMG activity during tongue-palate pressure tasks: A within-subject repeated-measures experimental study

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Background The stomatognathic system integrates cervical, masticatory, and hyoid subsystems that cooperate to perform essential orofacial functions. Although cervical posture influences tongue strength and mandibular behavior, its effect on neuromuscular coordination during tongue exertion remains unclear. Objectives To investigate the effects of experimental craniocervical motion restriction on the electromyographic (EMG) activity of cervical, masticatory, and hyoid muscles during maximal isometric tongue–palate pressure. Methods A within-subject repeated-measures study was conducted in 33 healthy adults (35.06 ± 15.43 years). EMG activity of the sternocleidomastoid, trapezius, temporalis, masseter, suprahyoid, and infrahyoid muscles was recorded during tongue-pressure tasks in the anterior, middle, and posterior regions using the Iowa Oral Performance Instrument (IOPI), with and without craniocervical motion restriction induced by a Minerva collar. Results Craniocervical motion restriction significantly increased EMG activity in the suprahyoid, infrahyoid, temporalis, and masseter muscles, with the strongest effects observed in the suprahyoid muscles (e.g., anterior region: adjusted p=0.009, d=0.90). A trend toward increased sternocleidomastoid activation was observed during posterior tongue tasks (adjusted p=0.100, d=0.45), whereas trapezius remained unchanged. Correlation analyses revealed moderate-to-strong associations between the masseter and hyoid muscles across conditions (ρ = 0.449–0.663), as well as increased coupling between the sternocleidomastoid and suprahyoid muscles under cervical restriction. Conclusion Craniocervical mobility restriction alters muscle activation patterns during tongue–palate pressure, particularly by increasing hyoid and masticatory muscles activity. These findings highlight the interdependence of the stomatognathic system and support the relevance of cervical posture in orofacial rehabilitation.