Original ArticleActivation of Rectus Capitis Posterior Major Muscles During Voluntary Retraction of the Head in Asymptomatic Subjects

ObjectiveThe purpose of this study was to assess levels of electromyographic activity measured from rectus capitis posterior major (RCPM) muscles of asymptomatic subjects as their heads moved from a self-defined neutral position to a retracted position.MethodsA 2 × 2 within-subjects factorial research design was used. Disposable, intramuscular electrodes were used to collect electromyographic data from asymptomatic subjects between the ages of 20 and 40 years old. Data analysis was performed using mixed effects β regression models.ResultsActivation of RCPM muscles was found to significantly increase (P < .0001) as the head moved from a self-defined neutral position to a retracted position. Rectus capitis posterior major muscle activation levels, measured as a function of head position, have not been previously reported.ConclusionsThe findings from this study showed that RCPM muscle activation significantly increases during voluntary retraction of the head.