title: Activation of rectus capitis posterior major muscles during voluntary retraction of the head in asymptomatic subjects.
abstract: OBJECTIVE
  The 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.
  
  
  METHODS
  A 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.
  
  
  RESULTS
  Activation 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.
  
  
  CONCLUSIONS
  The findings from this study showed that RCPM muscle activation significantly increases during voluntary retraction of the head.
authors.affiliation: Professor, Department of Physical Medicine & Rehabilitation, Michigan State University, East Lansing, MI; Professor, Department of Osteopathic Manipulative Medicine, Michigan State University, East Lansing, MI. Electronic address: hallgren@msu.edu.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Hallgren
authors.affiliation: Associate Professor, Department of Physical Medicine & Rehabilitation, Michigan State University, East Lansing, MI; Associate Professor, Department of Osteopathic Manipulative Medicine, Michigan State University, East Lansing, MI.
authors.forename: Jacob J
authors.initials: JJ
authors.lastname: Rowan
authors.affiliation: Clinical Assistant Professor, Department of Physical Medicine & Rehabilitation, Michigan State University, East Lansing, MI.
authors.forename: Peng
authors.initials: P
authors.lastname: Bai
authors.affiliation: Specialist-Research, Center for Statistical Training and Consulting, Michigan State University, East Lansing, MI.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Pierce
authors.affiliation: Assistant Professor, Division of Anatomy, Department of Radiology, Michigan State University, East Lansing, MI.
authors.forename: Gail A
authors.initials: GA
authors.lastname: Shafer-Crane
authors.affiliation: Associate Professor, Department of Physical Medicine & Rehabilitation, Michigan State University, East Lansing, MI.
authors.forename: Lawrence L
authors.initials: LL
authors.lastname: Prokop
mesh_terms: D000328:Adult; D004576:Electromyography; D005260:Female; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D008297:Male; D009334:Neck Muscles / Q000502:physiology*
keywords: Electromyography; Exercise Therapy; Headache; Neck Muscles