“…Even less is known if changes in the frequency domain occur in the paravertebral muscles because of stretching induced by the Williams series exercises, and if there is a dose-response effect for the exercise sustaining time. It is relevant to investigate whether stretching durations routinely used in the clinical context for lumbar paravertebral muscles, modify the myoelectric activity characteristics of the multifidus since this muscle plays a relevant role in stabilizing the lumbopelvic region (18,19), including changes in lumbago sufferers (20). Therefore, the objective of this study was to verify whether stretching to paravertebral muscles changes the electromyographic activity characteristics of the lumbar multifidus.…”