SERRATUS ANTERIOR MUSCLE FATIGUE EFFECTS ON SCAPULAR KINEMATICS
2011
Hochschulschrift
Zugriff:
Background: Shoulder pain accounts for an average of 8.6 million physician visits each year in the United States. Subacromial Impingement syndrome is the most common diagnosis of shoulder pain, accounting for 44% to 65% of all complaints of shoulder pain during a physician's office visits. Methods: A protocol to bias fatigue the Serratus Anterior was used in conjunction with an electromagnetic motion capture system to track the 3D motion of the scapula and the electromyography signal of 4 muscles bilaterally in 17 subjects. The skin based motion sensors tracked humeral elevation and scapular upward rotation, internal rotation, and tilting relative to the thorax in 2 planes of elevation. The skin based electromyography sensors recorded signal from pectoralis major, serratus anterior, and upper and lower trapezius. Subjects performed 2 fatigue tasks and 3 sets of 2 kinematic tasks. Analysis: Scapular orientations relative to the thorax and electromyography signals for 3 fatigue conditions (Pre, Mid, Post) were analyzed in 10° increments for humeral elevations of 30° to 120° in the scapular plane and 30° to 110° in flexion. Electromyography signals were also analyzed while subjects held the two isometric fatigue tasks. All data were analyzed with repeated measure analysis of variance. Results: Non-dominant arms showed consistent increases in internal rotation, decreases in upward rotation, and increases in anterior tilting of the scapula relative to the thorax in flexion and the scapular plane as fatigue progressed. Dominant arms had a wider variety of motions, showing both increases and decreases in all scapular rotations. Indications of progressive muscle fatigue were found qualitatively from the first fatigue task; however, the quantitative data was inconclusive. A state of global shoulder fatigue was reached following the second fatigue task. Individual muscle contributions to motion were inconclusive. Conclusions: Non-dominant arms, when fatigue, show consistent kinematic alterations similar to those found in patients with subacromial impingement syndrome. Dominant arms show a variety of kinematic alterations, some of which similar to patients with subacromial impingement syndrome, suggesting compensation strategies are learned. If this is true, rehabilitation can affect these compensation strategies and, possibly, return patients to more healthy motions. Further studies are needed to validate the fatigue task and protocol.
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SERRATUS ANTERIOR MUSCLE FATIGUE EFFECTS ON SCAPULAR KINEMATICS
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Autor/in / Beteiligte Person: | Costantini, Oren |
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Veröffentlichung: | 2011 |
Medientyp: | Hochschulschrift |
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