Association Between Suboccipital Muscle Tone, Postural Balance, and Head Posture in Healthy Adults

Background/Objectives: The suboccipital muscles (SOMs) are rich in muscle spindles and play a critical role in proprioceptive input and postural control. However, the relationship between SOM tone, head posture, and balance performance remains unclear. Therefore, this study aimed to investigate the association between SOM tone and postural balance, including the craniovertebral angle (CVA), static balance, and dynamic balance, in healthy adults. Methods: A total of 112 healthy adults participated in this study. SOM, cervical extensor muscle (CEM), and upper trapezius muscle (UTM) tones were assessed. Head posture was evaluated by measuring the CVA. Static balance was assessed through the trajectory of the center of pressure (COP), whereas dynamic balance was evaluated using gait parameters. Results: Participants with a higher SOM tone exhibited a significantly smaller CVA, increased COP path length and velocity, and narrower step width during walking than did those with a lower tone. The regression analysis showed that SOM tone was significantly associated with CVA (β = -0.219, p = 0.020), COP path length (β = 0.308, p = 0.001) and velocity (β = 0.296, p = 0.002), and step width (β = -0.242, p = 0.014), whereas CEM and UTM tone were not significantly associated with these variables. Conclusions: These findings suggest that SOM tone may be associated with postural control characteristics among healthy adults.