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Updated: Feb 7, 2026

Measurement of Dynamic Scapular Kinematics Using an Acromion Marker Cluster to Minimize Skin Movement Artifact
Published on: February 10, 2015
Scapular muscles weakness in subjects with traumatic anterior glenohumeral instability
Walter Ansanello Netto1, Gisele Garcia Zanca1, Michele Forgiarini Saccol2
1Department of Physical Therapy, Federal University of São Carlos, São Carlos, SP, Brazil.
Objective:
To investigate possible alterations on scapular muscle strength in subjects with traumatic anterior glenohumeral instability.
Design:
Cross-sectional study.
Setting:
Laboratory setting.
Participants:
Fifty-two subjects of both sexes: 26 healthy and 26 with traumatic anterior glenohumeral instability.
Main Outcome Measures:
Subjects performed maximal isometric and concentric isokinetic contractions of shoulder protraction and retraction in scapular and sagittal planes, at slow (12.2 cm/s) and fast (36.6 cm/s) speeds.
Results:
Subjects with glenohumeral instability presented lower peak force of protraction and retraction during isometric and fast speed tests in the scapular plane; and of isometric protraction in the sagittal plane.
Conclusions:
People with traumatic anterior glenohumeral instability present muscle weakness of scapular protractors and retractors. Considering the importance of the scapulothoracic muscles for the dynamic stability of the glenohumeral joint, strengthening of these muscles is recommended for rehabilitation of traumatic anterior glenohumeral instability.
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