title: Evidence for a general stiffening motor control pattern in neck pain: a cross sectional study.
abstract: BACKGROUND
  Neck pain is associated with several alterations in neck motion and motor control. Previous studies have investigated single constructs of neck motor control, while few have applied a comprehensive set of tests to investigate cervical motor control. This comparative cross- sectional study aimed to investigate different motor control constructs in neck pain patients and healthy controls.
  
  
  METHODS
  A total of 166 subjects participated in the study, 91 healthy controls (HC) and 75 neck pain patients (NP) with long-lasting moderate to severe neck pain. Neck flexibility, proprioception, head steadiness, trajectory movement control, and postural sway were assessed using a 3D motion tracking system (Liberty). The different constructs of neck motion and motor control were based on tests used in previous studies.
  
  
  RESULTS
  Neck flexibility was lower in NP compared to HC, indicated by reduced cervical ROM and conjunct motion. Movement velocity was slower in NP compared to HC. Tests of head steadiness showed a stiffer movement pattern in NP compared to HC, indicated by lower head angular velocity. NP patients departed less from a predictable trajectory movement pattern (figure of eight) compared to healthy controls, but there was no difference for unpredictable movement patterns (the Fly test). No differences were found for postural sway in standing with eyes open and eyes closed. However, NP patients had significantly larger postural sway when standing on a balance pad. Proprioception did not differ between the groups. Largest effect sizes (ES) were found for neck flexibility (ES range: 0.2-0.8) and head steadiness (ES range: 1.3-2.0). Neck flexibility was the only construct that showed a significant association with current neck pain, while peak velocity was the only variable that showed a significant association with kinesiophobia.
  
  
  CONCLUSIONS
  NP patients showed an overall stiffer and more rigid neck motor control pattern compared to HC, indicated by lower neck flexibility, slower movement velocity, increased head steadiness and more rigid trajectory head motion patterns. Only neck flexibility showed a significant association with clinical features in NP patients.
authors.affiliation: Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. ingebrigt.meisingset@ntnu.no.
authors.forename: Ingebrigt
authors.initials: I
authors.lastname: Meisingset
authors.affiliation: Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. astrid.woodhouse@ntnu.no.
authors.forename: Astrid
authors.initials: A
authors.lastname: Woodhouse
authors.affiliation: Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. ann.k.stensdotter@hist.no.
authors.forename: Ann-Katrin
authors.initials: AK
authors.lastname: Stensdotter
authors.affiliation: Department of Engineering Cybernetics, Norwegian University of Science and Technology, Trondheim, Norway. oyvind.stavdahl@itk.ntnu.no.
authors.forename: Øyvind
authors.initials: Ø
authors.lastname: Stavdahl
authors.affiliation: Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. havard.w.loras@hist.no.
authors.forename: Håvard
authors.initials: H
authors.lastname: Lorås
authors.affiliation: Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. sigmund.gismervik@ntnu.no.|Department of Physical Medicine and Rehabilitation, St. Olavs University Hospital, Trondheim, Norway. sigmund.gismervik@ntnu.no.
authors.forename: Sigmund
authors.initials: S
authors.lastname: Gismervik
authors.affiliation: Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. hege.andresen@ntnu.no.
authors.forename: Hege
authors.initials: H
authors.lastname: Andresen
authors.affiliation: Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. kristianaus@hotmail.com.
authors.forename: Kristian
authors.initials: K
authors.lastname: Austreim
authors.affiliation: Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. ottar.vasseljen@ntnu.no.
authors.forename: Ottar
authors.initials: O
authors.lastname: Vasseljen
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002574:Cervical Vertebrae / Q000502:physiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009068:Movement / Q000502:physiology; D009333:Neck / Q000502:physiology*; D019547:Neck Pain / Q000503:physiopathology*; D004856:Postural Balance / Q000502:physiology; D011434:Proprioception / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology*; D011795:Surveys and Questionnaires