Blind Needling Accuracy in Lumbar Muscles

\*Method:\* * All interventions will be performed by a physical medicine and rehabilitation specialist with clinical experience. * After each intervention, the needle tip position will be evaluated by a second specialist with \*high-resolution linear probe ultrasound\*. * Targeted muscles: * \*Iliocostalis lumborum (ICL)\* * \*Longissimus thoracis (LT)\* * \*Multifidus (M)\* * Interventions will be performed from the right side, between the L2-L5 levels. * A total of \*three different dry needling applications\* will be performed for these three muscles for each participant. * When a total of \*20 participants\* is planned, \*60 injection attempts\* will be analyzed. * Will be used only for post-hoc observational validation purposes. * No pharmacological agent will be administered during the intervention, only dry needling will be performed.