Effects of a Sternocleidomastoid Muscle Exercise Protocol on Masticatory Muscles: A Case Study

Abstract

Introduction: TThe temporomandibular joint (TMJ) is fundamental for the postural tonic system, influencing and being influenced by postural alterations. Recent research emphasises the impact of sternocleidomastoid (SCM) stiffness on the range of movement of the cervical spine, especially during head rotation. Materials and Methods:A healthy adult woman (24 years, 1.65 m and 45 kg) participated in the study. Range of motion (ROM) was measured using the Euleria LabTM system and muscle activation was measured using the mDurance® surface electromyograph (sEMG). After the first measurement (T0), a protocol based on SCM resistance and flexibility exercises was administered. At the end of the procedure, the tests were repeated (T1). Results:In T0, asymmetries in temporal muscle activation (±38%) and significant differences in active and passive cervical ROMS were found, especially in rotation (-17°) and extension (-8°) movements. In T1, muscle activation levels are normalised with symmetry indices falling within the sufficiency ranges (±17%) and differences between active and passive ROMS significantly reduced in rotation (-9°) and absent in extension (-1°).Discussion: After the procedure there were improvements in the sEMG of all muscles examined and in the active cervical ROM.The study confirms the link between anterior neck muscles and masticatory muscles and demonstrates the immediate impact of improved distal muscle tension on proximal muscles.Future research aims to expand the sample size and evaluate the short term and long term effects of the procedure, as well as explore synergies with other treatment modalities for the comprehensive resolution of postural problems.