title: Shoulder kinematics is not influenced by external load during elevation in the scapular plane.
abstract: The current study aimed to compare the shoulder kinematics (3D scapular orientation, scapular angular displacement and scapulohumeral rhythm) of asymptomatic participants under unloaded and loaded conditions during unilateral shoulder elevation in the scapular plane. We used a repeated-measures design with a convenience sample. Eleven male participants with an age range of 21-28 years with no recent history of shoulder injury participated in the study. The participants performed isometric shoulder elevation from a neutral position to approximately 150 degrees of elevation in the scapular plane in intervals of approximately 30 degrees during unloaded and loaded conditions. Shoulder kinematic data were obtained with videogrammetry. During shoulder elevation, the scapula rotated upwardly and externally, and tilted posteriorly. The addition of an external load did not affect 3D scapular orientation, scapular angular displacement, or scapulohumeral rhythm throughout shoulder elevation (P > .05). In clinical practice, clinicians should expect to observe upward and external rotation and posterior tilt of the scapula during their assessments of shoulder elevation. Such behavior was not influenced by an external load normalized to 5% of body weight when performed in an asymptomatic population.
authors.affiliation: Center of Research, Education, Innovation and Intervention in Sport, School of Sport, University of Porto, Porto, Portugal, and with the Department of Physiotherapy, School of Allied Health Science, Polytechnic Institute of Porto, Vila Nova de Gaia, Portugal.
authors.forename: Marcelo P
authors.initials: MP
authors.lastname: de Castro
authors.forename: Daniel Cury
authors.initials: DC
authors.lastname: Ribeiro
authors.forename: Felipe de C
authors.initials: Fde C
authors.lastname: Forte
authors.forename: Joelly M
authors.initials: JM
authors.lastname: de Toledo
authors.forename: Daniela
authors.initials: D
authors.lastname: Aldabe
authors.forename: Jefferson F
authors.initials: JF
authors.lastname: Loss
mesh_terms: D000328:Adult; D006801:Humans; D017770:Lifting; D008297:Male; D005082:Physical Exertion / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology*; D012399:Rotation; D012540:Scapula / Q000502:physiology*; D012785:Shoulder Joint / Q000502:physiology*; D013647:Task Performance and Analysis; D016474:Weight-Bearing / Q000502:physiology*