IntroductionThis study investigated the effect of the lumbar rotation rhythmic mobilization technique in grade IV on the electromyographic activity of the erector spinae as well as on the lumbar range of motion during trunk flexion-extension. MethodologyTwelve asymptomatic adult participants performed 5flexion-extension movements before and after the intervention. The electromyographic activity of the erector spinae (longissimus thoracis) at the level of L3 and L5 was recorded bilaterally, as well as the kinematic data to evaluate the movement patterns of the lumbopelvic region. The variables recorded before and after performing the Maitland grade IV oscillatory rhythmic mobilization on the lumbar region in the direction of left rotation were compared. Mobilization was applied unilaterally with the patient in right lateral decubitus on the stretcher. ResultsThere was a statistically significant decrease (p<0.01) in the EMG activity of the erector spinae during the maximum flexion phase on the right side at the L3 level after the application of the studied technique. No difference was observed at the L5 level, nor were significant differences in lumbopelvic kinematics. ConclusionThis study demonstrates that a rhythmic oscillatory mobilization towards the left side in grade IV lumbar rotation produces a statistically significant decrease in the electromyographic activity of the erector spinae in the phase of full flexion on the contralateral (right) side, at the level vertebral column of its application (L3) and not at lower levels (L5).