title: Electromyographic activity of the trunk extensor muscles: effect of varying hip position and lumbar posture during Roman chair exercise.
abstract: OBJECTIVE
  To evaluate the effect of hip position and lumbar posture on the surface electromyographic activity of the trunk extensors during Roman chair exercise.
  
  
  METHODS
  Descriptive, repeated measures.
  
  
  METHODS
  University-based musculoskeletal research laboratory.
  
  
  METHODS
  Twelve healthy volunteers (7 men, 5 women; age range, 18-35y) without a history of low back pain were recruited from a university setting.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Surface electromyographic activity was recorded from the lumbar extensor, gluteal, and hamstring musculature during dynamic Roman chair exercise. For each muscle group, electromyographic activity (mV/rep) was compared among exercises with internal hip rotation and external hip rotation and among exercises by using a typical lumbar posture (nonbiphasic) and a posture that accentuated lumbar lordosis (biphasic).
  
  
  RESULTS
  For the lumbar extensors, electromyographic activity during exercise was 18% greater with internal hip rotation than external hip rotation (P< or =.05) and was 25% greater with a biphasic posture than with a nonbiphasic posture (P< or =.05). For the gluteals and hamstrings, there was no difference in electromyographic activity between internal and external hip rotation or between biphasic and nonbiphasic postures (P >.05).
  
  
  CONCLUSIONS
  The level of recruitment of the lumbar extensors can be modified during Roman chair exercise by altering hip position and lumbar posture. Clinicians can use these data to develop progressive exercise protocols for the lumbar extensors with a variety of resistance levels without the need for complex equipment.
authors.affiliation: US Spine & Sport Foundation-San Diego, 0532 Via Mallorca, D, La Jolla, CA 92037, USA. jmmayer@mail.sdsu.edu
authors.forename: John M
authors.initials: JM
authors.lastname: Mayer
authors.forename: Joe L
authors.initials: JL
authors.lastname: Verna
authors.forename: Todd M
authors.initials: TM
authors.lastname: Manini
authors.forename: Vert
authors.initials: V
authors.lastname: Mooney
authors.forename: James E
authors.initials: JE
authors.lastname: Graves
mesh_terms: D000293:Adolescent; D000328:Adult; D001415:Back / Q000502:physiology*; D001696:Biomechanical Phenomena; D002081:Buttocks / Q000503:physiopathology; D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006615:Hip / Q000502:physiology*; D006801:Humans; D017116:Low Back Pain / Q000209:etiology / Q000503:physiopathology / Q000534:rehabilitation; D008161:Lumbosacral Region / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D016059:Range of Motion, Articular; D012399:Rotation; D013848:Thigh / Q000503:physiopathology