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Strength and muscle activity of shoulder external rotation of subjects with and without scapular dyskinesis

[Purpose] This study aimed to clarify the relationship between scapular dyskinesis and shoulder external rotation strength and muscle activity. [Subjects and Methods] Both shoulders of 20 healthy males were evaluated. They were classified into 19 normal, 8 subtly abnormal, and 13 obviously abnormal...

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Detalles Bibliográficos
Autores principales: Uga, Daisuke, Nakazawa, Rie, Sakamoto, Masaaki
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Society of Physical Therapy Science 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4868194/
https://www.ncbi.nlm.nih.gov/pubmed/27190434
http://dx.doi.org/10.1589/jpts.28.1100
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author Uga, Daisuke
Nakazawa, Rie
Sakamoto, Masaaki
author_facet Uga, Daisuke
Nakazawa, Rie
Sakamoto, Masaaki
author_sort Uga, Daisuke
collection PubMed
description [Purpose] This study aimed to clarify the relationship between scapular dyskinesis and shoulder external rotation strength and muscle activity. [Subjects and Methods] Both shoulders of 20 healthy males were evaluated. They were classified into 19 normal, 8 subtly abnormal, and 13 obviously abnormal shoulders using the scapular dyskinesis test. Subtly abnormal shoulders were subsequently excluded from the analysis. Shoulder external rotation strength and muscle activity (infraspinatus, serratus anterior, upper, middle, and lower trapezius) were measured in 2 positions using a handheld dynamometer and surface electromyography while sitting in a chair with shoulder 0° abduction and flexion (1st position), and while lying prone on the elbows with the shoulders elevated in the zero position (zero position). The strength ratio was calculated to quantify the change in strength between the positions (zero position / 1st position). [Results] In the obviously abnormal shoulder group, the strength in the 1st position was significantly stronger, the strength ratio was significantly smaller, and the serratus anterior in the zero position showed significantly lower activity than the normal shoulder group. [Conclusion] In shoulder external rotation in the zero position, in obviously abnormal shoulders, the serratus anterior is poorly recruited, weakening the shoulder external rotation strength.
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spelling pubmed-48681942016-05-17 Strength and muscle activity of shoulder external rotation of subjects with and without scapular dyskinesis Uga, Daisuke Nakazawa, Rie Sakamoto, Masaaki J Phys Ther Sci Original Article [Purpose] This study aimed to clarify the relationship between scapular dyskinesis and shoulder external rotation strength and muscle activity. [Subjects and Methods] Both shoulders of 20 healthy males were evaluated. They were classified into 19 normal, 8 subtly abnormal, and 13 obviously abnormal shoulders using the scapular dyskinesis test. Subtly abnormal shoulders were subsequently excluded from the analysis. Shoulder external rotation strength and muscle activity (infraspinatus, serratus anterior, upper, middle, and lower trapezius) were measured in 2 positions using a handheld dynamometer and surface electromyography while sitting in a chair with shoulder 0° abduction and flexion (1st position), and while lying prone on the elbows with the shoulders elevated in the zero position (zero position). The strength ratio was calculated to quantify the change in strength between the positions (zero position / 1st position). [Results] In the obviously abnormal shoulder group, the strength in the 1st position was significantly stronger, the strength ratio was significantly smaller, and the serratus anterior in the zero position showed significantly lower activity than the normal shoulder group. [Conclusion] In shoulder external rotation in the zero position, in obviously abnormal shoulders, the serratus anterior is poorly recruited, weakening the shoulder external rotation strength. The Society of Physical Therapy Science 2016-04-28 2016-04 /pmc/articles/PMC4868194/ /pubmed/27190434 http://dx.doi.org/10.1589/jpts.28.1100 Text en 2016©by the Society of Physical Therapy Science. Published by IPEC Inc. http://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives (by-nc-nd) License.
spellingShingle Original Article
Uga, Daisuke
Nakazawa, Rie
Sakamoto, Masaaki
Strength and muscle activity of shoulder external rotation of subjects with and without scapular dyskinesis
title Strength and muscle activity of shoulder external rotation of subjects with and without scapular dyskinesis
title_full Strength and muscle activity of shoulder external rotation of subjects with and without scapular dyskinesis
title_fullStr Strength and muscle activity of shoulder external rotation of subjects with and without scapular dyskinesis
title_full_unstemmed Strength and muscle activity of shoulder external rotation of subjects with and without scapular dyskinesis
title_short Strength and muscle activity of shoulder external rotation of subjects with and without scapular dyskinesis
title_sort strength and muscle activity of shoulder external rotation of subjects with and without scapular dyskinesis
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4868194/
https://www.ncbi.nlm.nih.gov/pubmed/27190434
http://dx.doi.org/10.1589/jpts.28.1100
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