title: Electromyographic activity of rectus capitis posterior minor muscles associated with voluntary retraction of the head.
abstract: BACKGROUND
  The functional role of rectus capitis posterior minor (RCPm) muscles is not well defined. To the best of our knowledge, electromyographic (EMG) data from RCPm muscles in humans have never been collected and analyzed.
  
  
  OBJECTIVE
  To test the null hypothesis that there will be no difference in normalized levels of EMG activity measured from RCPm muscles with the head in a neutral position and with the head in a retracted position.
  
  
  METHODS
  A repeated measures design intended to quantify normalized levels of EMG activity measured from RCPm muscles.
  
  
  METHODS
  Disposable 25-gauge, bipolar fine wire hooked electrodes were used to collect EMG data from both right and left RCPm muscles from 17 asymptomatic subjects. Data were collected while subjects performed five trials with the head maintained in a neutral position; performed three maximal voluntary isometric contraction efforts; performed four trials with the head maintained in a retracted position. Mixed effects beta regression models were used to analyze the data.
  
  
  RESULTS
  Normalized EMG activity of RCPm muscles collected with the subject's head held in a retracted position was significantly higher (p<.0001) than normalized EMG activity collected with the subject's head held in a self-selected, neutral position.
  
  
  CONCLUSIONS
  Rectus capitis posterior minor muscles are active when the head is held in a neutral position and show a significant increase in activity when the head is held in a retracted position.
authors: Department of Physical Medicine & Rehabilitation, Michigan State University, 909 Fee Rd, East Lansing, MI 48824, USA; Department of Osteopathic Manipulative Medicine, Michigan State University, 909 Fee Rd, East Lansing, MI 48824, USA. Electronic address: hallgren@msu.edu.
authors: Richard C
authors: RC
authors: Hallgren
authors: Center for Statistical Training and Consulting, Michigan State University, 293 Farm Lane Rd, Room 178, East Lansing, MI 48824, USA.
authors: Steven J
authors: SJ
authors: Pierce
authors: Department of Physical Medicine & Rehabilitation, Michigan State University, 909 Fee Rd, East Lansing, MI 48824, USA.
authors: Lawrence L
authors: LL
authors: Prokop
authors: Department of Osteopathic Manipulative Medicine, Michigan State University, 909 Fee Rd, East Lansing, MI 48824, USA.
authors: Jacob J
authors: JJ
authors: Rowan
authors: Michigan State University Center for Orthopedic Research, Michigan State University, 2727 South Pennsylvania Ave, East Lansing, MI 48824, USA.
authors: Angela S
authors: AS
authors: Lee
mesh_terms: D000328:Adult; D004576:Electromyography; D005260:Female; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D009334:Neck Muscles / Q000502:physiology*; D055815:Young Adult
keywords: Electromyography; Functional role; Head retraction; Neck muscles; Rectus capitis posterior