Banca de DEFESA: PALOMA DAIANE BEATRIS ALMEIDA DE SENA

COMPARISON OF MUSCLE STRENGTH AND ELECTROMYOGRAPHIC ACTIVITY BETWEEN ASYMPTOMATIC SUBJECTS AND SUBACROMIAL PAIN.

Subacromial pain syndrome. Muscle strength. Electromyography

Background: Alterations in muscle activation and force production in the scapulohumeral joint are frequently associated with Subacromial Pain Syndrome (SPS). However, studies that evaluate variables related to the onset of the firing time of the scapular stabilizing muscles in these subjects, comparing them to an asymptomatic control group, are still scarce. Thus, comparing muscle strength and static and dynamic muscle activity between individuals with SPS and asymptomatic individuals may provide information on normal and altered muscle aspects in this patient population, which should be considered in the exercise planning approach for the rehabilitation of these individuals. Objective: To compare muscle strength and electromyographic activity of the shoulder muscles between asymptomatic individuals and individuals with SPS. Methodology: Cross-sectional study. Individuals of both sexes aged between 35 and 60 years diagnosed with SPS were recruited and compared to asymptomatic individuals, matched for age, weight, height, sex, limb dominance and level of physical activity. Muscle strength was measured with a Lafayette Instrument® hand-held digital dynamometer and electromyographic amplitude was checked with a TeleMyo signal conditioning module (Noraxon®, USA) using passive self-adhesive surface electrodes. Results: Reduction of internal and external rotation strength and flexion was found in the shoulder of the SPS group, compared to the asymptomatic subjects (p< 0.05).  The serratus anterior muscle in the SPS group showed decreased activity at all evaluated humeral elevation angles and a delayed onset of firing time during full shoulder elevation when compared to the control group. Conclusion: The strength of the flexors, lateral and medial rotators of the shoulder and the function of the serratus anterior muscle are important to consider in the rehabilitation of patients with symptoms of subacromial pain syndrome.