Estudo eletromiográfico do longuíssimo lombar, iliocostal e glúteo médio nos movimentos de levantar, sentar, durante a marcha e correlação com o ângulo de Cobb em adolescentes com escoliose idiopática

Abstract

INTRODUCTION: Idiopathic scoliosis (IS) is the major cause of deformity in the adolescent spine. Surface electromyography (sEMG) has been considered a valid instrument for the evaluation of electrical activation among the paravertebral muscles. However, a few authors have studied the muscles activation of the Longissimus lumbar (Long), Iliocostalis (Ilio) and Gluteus Medius (Gme) during dynamic activities. OBJECTIVE: To evaluate the electrical activation of the Long, Ilio and Gme muscles on the concave (Cv) and convex (Cx) sides of the adolescents lumbar spine with IS during the standing, sitting and walking movements and to correlate this activation with the Cobb angle. METHODS: A cross-sectional study was performed in 15 adolescents, right-handed, diagnosed by means of x-ray to measure Cobb angle with lumbar IS between 10 and 32º. EMGs were recorded using surface electrodes placed on Long, Ilio and Gme muscles. The footswitch was placed under the calcaneus for temporal marking in parallel with the EMGs for 1 min. The signals were processed in MATLAB and the RMS amplitude was estimated. RESULTS: There was a significant difference between the Cv and Cx sides, in the Long muscles during the standing movement (P=0.026) and during sitting movement (P=0.015). On gait, there was a significant difference in Long, at the beginning of the support phase (P=0.007). Ilio muscle on the Cx side presented a correlation with the Cobb angle, during standing (P=0.003, r=0.71) and sitting (P=0.03, r=0.55). CONCLUSION: There seems to be an asymmetry in Long muscle recruitment during standing and sitting, and at the beginning of the support phase. In addition, the Ilio correlates with the Cobb angle during standing and sitting.