title: Three-dimensional comparison of static and dynamic scapular motion tracking techniques.
abstract: The shoulder is complex and comprised of many moving parts. Accurately measuring shoulder rhythm is difficult. To classify shoulder rhythm and identify pathological movement, static measures have been the preferred method. However, dynamic measures are also used and can be less burdensome to obtain. The purpose of this paper was to determine how closely dynamic measures represent static measures using the same acromion marker cluster scapular tracking technique. Five shoulder angles were assessed for 24 participants using dynamic and static tracking techniques during humeral elevation in three planes (frontal, scapular, sagittal). ANOVAs were used to identify where significant differences existed for the factors of plane, elevation angle, and tracking technique (static, dynamic raising, dynamic lowering). All factors were significantly different for all shoulder angles (p<0.001), except for elevation plane in scapulothoracic protraction/retraction (p=0.955). Tracking techniques were influential (p<0.001), but the grouped mean differences fell below a clinically relevant 5° benchmark. There was large variation in mean differences of the techniques across individuals. While population averages are similar, individual static and dynamic shoulder assessments may be different. Caution should be taken when dynamic shoulder assessments are performed on individuals, as they may not reflect those obtained in static scapular motion tracking.
authors.affiliation: Department of Kinesiology, University of Waterloo, Waterloo N2L 3G1, Canada.
authors.forename: Kathleen F E
authors.initials: KF
authors.lastname: MacLean
authors.affiliation: Department of Kinesiology, University of Waterloo, Waterloo N2L 3G1, Canada.
authors.forename: Jaclyn N
authors.initials: JN
authors.lastname: Chopp
authors.affiliation: Department of Kinesiology, University of Waterloo, Waterloo N2L 3G1, Canada.
authors.forename: Tej-Jaskirat
authors.initials: TJ
authors.lastname: Grewal
authors.affiliation: Department of Kinesiology, University of Waterloo, Waterloo N2L 3G1, Canada.
authors.forename: Bryan R
authors.initials: BR
authors.lastname: Picco
authors.affiliation: Department of Kinesiology, University of Waterloo, Waterloo N2L 3G1, Canada. Electronic address: clark.dickerson@uwaterloo.ca.
authors.forename: Clark R
authors.initials: CR
authors.lastname: Dickerson
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D006811:Humerus / Q000502:physiology; D008297:Male; D009038:Motion; D009068:Movement; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal; D016059:Range of Motion, Articular / Q000502:physiology*; D012016:Reference Values; D012399:Rotation; D012540:Scapula / Q000502:physiology*; D012785:Shoulder Joint / Q000502:physiology*
keywords: Biomechanics; Scapular motion; Shoulder rhythm; Static and dynamic movement