title: Co-contractive activation of the superficial multifidus during volitional preemptive abdominal contraction.
abstract: OBJECTIVE
  To investigate whether the superficial multifidus (MF) muscle at the lower lumbar spine displayed co-contraction during volitional preemptive abdominal contraction (VPAC) through the abdominal drawing-in maneuver (ADIM) or the abdominal bracing maneuver (ABM) in 3 different postural positions.
  
  
  METHODS
  A within-subject cohort design.
  
  
  METHODS
  A clinical laboratory.
  
  
  METHODS
  A healthy convenience sample of 21 women and 13 men; mean age (SD), 25.5 ± 6.5 years.
  
  
  METHODS
  We collected surface electromyographic measurements for the superficial MF at the L5 vertebral level and abdominal wall muscles. Ultrasound imaging was used during screening and testing sessions for confirming transverse abdominis muscle activation while subjects maintained a relaxed state without volitional abdominal contraction (no-VPAC) and performed ADIM and ABM in 3 postural positions: supine, 4-point kneeling, and upright standing.
  
  
  METHODS
  The frequency of superficial MF co-contraction occurrences (percentage of the total number of conditions) was measured during ADIM and ABM in 3 different postural positions.
  
  
  METHODS
  A Cochran Q test for k-related samples (α = 0.05) was used for data analysis.
  
  
  RESULTS
  Activation of the abdominal wall by using either VPAC strategy resulted in a significantly greater MF co-contraction occurrence when compared with no-VPAC in each position. The ABM produced a significantly higher MF co-contractive occurrence versus the ADIM in the supine position.
  
  
  CONCLUSIONS
  Both VPAC strategies produced a co-contractive MF response, which appears to be important for lumbar segmental stabilization and control. Analysis of the results suggests that VPAC strategies are appropriate for coactivating the MF, which can enhance spinal protection and rehabilitation responses.
authors.affiliation: Center for Rehabilitation Research, School of Allied Health Sciences, Texas Tech University Health Science Center, Lubbock, TX(∗).
authors.forename: Omer C G
authors.initials: OC
authors.lastname: Matthijs
authors.affiliation: Doctor of Physical Therapy Program, College of Pharmacy and Health Sciences, Campbell University, Buies Creek, NC(†).
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Dedrick
authors.affiliation: Center for Rehabilitation Research, School of Allied Health Sciences, Texas Tech University Health Science Center, Lubbock, TX(‡).
authors.forename: C Roger
authors.initials: CR
authors.lastname: James
authors.affiliation: Center for Rehabilitation Research, School of Allied Health Sciences, Texas Tech University Health Science Center, Lubbock, TX(§).
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Brismée
authors.affiliation: Center for Rehabilitation Research, School of Allied Health Sciences, Texas Tech University Health Science Center, Lubbock, TX(‖).
authors.forename: Troy L
authors.initials: TL
authors.lastname: Hooper
authors.affiliation: Doctor of Physical Therapy Program, Harding University, Searcy, AR(#).
authors.forename: Michael K
authors.initials: MK
authors.lastname: McGalliard
authors.affiliation: Center for Rehabilitation Research, School of Allied Health Sciences, Texas Tech University Health Science Center, 3601 4th Street, Stop 6280, Lubbock, TX 79430-6280(¶). Electronic address: phil.sizer@ttuhsc.edu.
authors.forename: Phillip S
authors.initials: PS
authors.lastname: Sizer
mesh_terms: D000005:Abdomen; D000328:Adult; D015331:Cohort Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D064170:Paraspinal Muscles / Q000000981:diagnostic imaging / Q000502:physiology*; D011187:Posture / Q000502:physiology; D014463:Ultrasonography