Reproducibility of isometric shoulder protraction and retraction strength measurements in normal subjects and individuals with winged scapula.
BACKGROUND
The strength of the shoulder protractors and retractors may be compromised in individuals with winged scapula (IwWS). However, no standard approach to measuring the strength of these muscles has been described. The aim of this study was to study the intra-rater and inter-rater reproducibility of a fixed-base isometric dynamometer and to describe cutoff scores for clinically meaningful change for protraction and retraction isometric strength.


METHODS
Twice during a week, 20 normal subjects and 20 IwWS were tested by 2 independent raters.


RESULTS
IwWS were significantly weaker (P < .001) than control subjects in their protraction and retraction isometric strength. Excellent intra-rater and inter-rater correlations were obtained in most combinations, leading to low cutoff scores for meaningful change expressed in terms of the smallest real difference.


CONCLUSIONS
When it is properly used, the technique described in this paper is recommended as an effective clinical tool for the quantitative assessment of protraction and retraction isometric strength, both for status determination and for monitoring of change in IwWS during and after rehabilitation.
Department of Physical Therapy, College of Biomedical Science and Engineering, Inje University, Gimhae, Republic of Korea.
Jae-Seop
JS
Oh
Department of Physical Therapy, Graduate School, Inje University, Gimhae, Republic of Korea.
Min-Hyeok
MH
Kang
Department of Physical Therapy, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. Electronic address: zdvir@post.tau.ac.il.
Zeevi
Z
Dvir
D000328:Adult; D016022:Case-Control Studies; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D015203:Reproducibility of Results; D019534:Shoulder Impingement Syndrome / Q000503:physiopathology*; D012785:Shoulder Joint / Q000503:physiopathology*
Protraction; reproducibility; retraction; shoulder; strength; winged scapula