Torque e perfil eletromiográfico de mulheres sedentárias durante a rotação externa do ombro em duas diferentes posturas escapulares

Abstract

Introduction: Previous researches suggested changes in external rotation (ER) exercises and aerobic exercises for blocked muscles without controlling the static and dynamic changes of the scapular waist, without taking into account the behavior of muscle torque and the overload applied to the myotendinous junction. Objective: to analyze the profile of muscle recruitment through the analysis of isometric muscle torque and surface electromyography (EMGs), rotator cuff (CR) and shoulder girdle muscles in twelve different shoulder RE exercises in two scapular dimensions. Method: This is a cross-sectional study, composed of thirty female participants, with a mean standard deviation (± SD) of 21 ± 2.30 years, body mass of 55.99 ± 6.02 kg, height of 1 , 61 m ± 0.05 and BMI of 21.50 ± 1.98 kg / m2, all classified as sedentary and insufficiently activated, with no history of trauma and complaints of pain in the shoulder joint in the last two months. Analysis of isometric muscle torque and EMG activity of the upper, middle and lower trapezius muscles, anterior serratus, infraspinatus and minor round in RE shoulder exercises compared to an ER control condition with 30º internal test (CER) transducer of isometric strength and an electromyographic system. Results: A statistically significant difference was found in the relative torque (τ%) of the ER resting conditions compared to the REC, (F12.377 = 21.236, p <0.001). In the analysis of scapular positioning during the twelve ER conditions, six conditions with anatomical position scanning (ER1A - ER6A) and with the same six slipping in the retraction position (ER1R - ER6R), observed that the ER with retracted scapula did not result in a greater production of τ% when compared with a scapula in the anatomical position (p <0.001). When analyzing or τ% of each condition of ER, observe that a condition of RE1A (ER in prone with shoulder abducted 90º with scapula of anatomical position) and RE1R (RE in prone with shoulder abducted 90º with escape from retraction position) presented greater generation of τ% (p <0.0280) when compared to other ER conditions with both an anatomical and retracted position and in relation to the CER (p <0.0041), except when compared to the RE3A condition (RE in the sitting position) with shoulder abducted at 90 ° with scapula in anatomical position) and his condition conditioned with the retracted scapula RE3R (p= 1.0000). Conclusion: The condition of CER was not observed as the most efficient from the biomechanical point of view, and a condition that demonstrated greater generation of isometric muscle torque with possible biomechanical efficiency was an ER in a contract with an abducted shoulder 90º with a listening position anatomical, as well as in the retraction position, represented by ER1A / ER1R, which is the least electromyographic activity of the primary motor external rotator muscles, in addition to the lower perception of effort, represented by the borg scale