Efficacy of Instrument-assisted soft tissue mobilization (IASTM) vs Mulligan Technique for Nonspecific Neck Pain in Older Adults

Arm 1 – IASTM Group: Participants will receive an Instrument-Assisted Soft Tissue Mobilization (IASTM) protocol consisting of five structured phases applied to the upper trapezius muscle. The five phases are: Passive IASTM mobilization Active movement during IASTM application Resisted movement during IASTM application Proprioceptive stimulation using closed kinetic chain tasks (e.g., pushing a stability ball against the wall at 90° shoulder flexion) Return to calm through passive IASTM mobilization Each session lasts approximately 30 minutes, and the protocol is applied once per week for 6 weeks. Sessions are delivered in a one-on-one format, administered by a licensed physiotherapist trained in IASTM application. The setting is a physiotherapy clinic in the Biobío region of Chile. Fidelity monitoring will be performed through a session checklist, therapist documentation of completed steps, and participant attendance logs. Arm 2 – MWM Group: Participants will receive treatment based on the Mulligan concept, which incorporates Mobilization with Movement (MWM) techniques. The protocol includes: Natural Apophyseal Glides (NAGs): Low-velocity central mobilizations in seated position Sustained Natural Apophyseal Glides (SNAGs): Combined therapist-applied glides with active cervical movements (e.g., flexion, extension, side bending) Manual and belt-assisted distraction techniques in supine position Functional movement retraining with overpressure A typical session lasts approximately 30 minutes, and treatment is provided once per week for 6 weeks. Interventions are administered by a physiotherapist certified in the Mulligan concept, delivered in a one-on-one format at a physiotherapy clinic in the Biobío region. To ensure procedural fidelity, a standardized treatment protocol will be followed, with therapists completing structured documentation of techniques performed and patient response, alongside attendance logs.