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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.
Marcelo P. de Castro (Corresponding Author) is with the 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. Daniel Cury Ribeiro is with the School of Physiotherapy, University of Otago, Dunedin, New Zealand. Felipe de C. Forte is with the Worcestershire Acute Hospitals NHS Trust, Worcester, Worcestershire, U.K., and with Coventry University, Coventry, Warwickshire, U.K. Joelly M. de Toledo is with the Exercise Research Laboratory, School of Physical Education, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. Daniela Aldabe is with the Rede Metodista de Educação do Sul—IPA, Porto Alegre, RS, Brazil, and with the School of Physical Education, University of Otago, Dunedin, Otago, New Zealand. Jefferson F. Loss is with the Exercise Research Laboratory, School of Physical Education, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.