Intra and inter-examiner reliability of scapular protraction force measurements in individuals with shoulder pain

Abstract

Among the muscles that compose the shoulder, the serratus anterior is one of the most clinically relevant, and the reduction of its strength can cause problems such as painful impact, defective glenohumeral kinematics, and scapular dyskinesia, which emphasizes the importance of its evaluation. Detailed diagnosis, performed through anamnesis and evaluation with a range of motion and manual muscular tests (MMT), is fundamental to define the degree of functionality and rehabilitation conduits for a good prognosis. However, MMT has some subjectivity being subject to variations, such as the resistance that each examiner applies and the non-distinction of the various degrees of muscle weakness. More accurate valid methods already exist, such as isokinetic dynamometry and manual dynamometry with the use of a hand-held dynamometer (HHD) which has greater benefits for its easy applicability, portability, and relatively low cost, however, there are limitations such as the stabilization of the device by the therapist and the clinical non-reproducibility and load limitation of certain fixed-base devices. Moreover, there is currently a lack of studies analyzing intra- and inter-examiner reliability in measures of scapular protraction force and different positions for the scapulothoracic joint. There is limited evidence with low symptomatic shoulder sample size and a tendency to lower reliability values. Therefore, the present study aims to evaluate intra-examiner reliability within a range of 3 to 7 days between data collection, and inter-examiner with a 15-minute interval analyzing the average force of 3 shoulder protraction measurements obtained by the portable dynamometer stabilized by a rigid belt in sitting and supine positions, as well as Standard Error Measurement (SEM) and Minimum Change Detectable (MCD). Will be selected 100 individuals of both genders, at least 18 years old who present symptoms of unilateral subacromial pain syndrome for at least 6 months. Statistical analysis of the study data will be performed through the Statistical Package for the Social Sciences program (SPSS-20.0). The level of significance adopted will be pd0.05. As a result of this study, the analyzes are expected to show good to excellent reliability of scapulothoracic measurements for both intra-examiner and intra-examiner shoulder protraction movement through the HHD.