Effects of Instrument-Assisted Soft Tissue Mobilization Versus Post Facilitation Stretch Technique in Chronic Neck Pain

Chronic neck pain (CNP) is one of the most prevalent musculoskeletal disorders worldwide and is a major contributor to pain, disability, reduced work productivity, and poor quality of life. It is defined as pain or discomfort in the cervical region persisting for more than 12 weeks and is commonly associated with muscle tightness, soft tissue restrictions, reduced cervical range of motion (ROM), impaired neuromuscular control, and functional limitations that interfere with daily activities. The condition has a multifactorial etiology involving mechanical, postural, ergonomic, and psychosocial factors. Prolonged forward head posture, repetitive occupational tasks, and extended use of computers and digital devices increase mechanical stress on cervical structures, leading to muscle fatigue, ligamentous strain, joint dysfunction, and persistent pain. Chronic neck pain frequently affects the upper trapezius, levator scapulae, and suboccipital muscles, resulting in movement impairments and decreased functional capacity. Despite the widespread use of physiotherapy interventions, uncertainty remains regarding the comparative effectiveness of several commonly used manual therapy techniques. Instrument-Assisted Soft Tissue Mobilization (IASTM) and Post Facilitation Stretch (PFS) are two manual therapy techniques frequently used in clinical physiotherapy practice to improve pain, tissue mobility, flexibility, and function. IASTM utilizes specialized instruments to apply controlled mechanical pressure to soft tissues with the aim of reducing myofascial restrictions, improving circulation, promoting tissue remodeling, and restoring mobility. PFS is a muscle energy-based stretching technique that combines a brief submaximal isometric contraction with passive stretching to facilitate neuromuscular inhibition, decrease muscle tightness, and improve muscle flexibility. Although previous studies have demonstrated beneficial effects of both interventions individually, there is limited evidence directly comparing their effectiveness in individuals with chronic neck pain, particularly when multiple clinically important cervical muscles are treated. Therefore, further comparative research is needed to guide evidence-based clinical decision-making. The primary objective of this randomized controlled trial is to compare the effects of Instrument-Assisted Soft Tissue Mobilization and Post Facilitation Stretch on pain intensity, cervical range of motion, and neck-related disability in individuals with chronic neck pain. The study seeks to determine whether one intervention provides superior clinical outcomes and to generate evidence that may improve rehabilitation strategies for this patient population. This randomized controlled trial will be conducted over a period of one year at the Foundation University College of Physical Therapy, Islamabad. Participants will be recruited using a non-probability purposive sampling technique. Individuals aged 18-50 years with non-specific chronic neck pain of at least 12 weeks' duration, a Numeric Pain Rating Scale (NPRS) score of 3 or greater, painful or restricted cervical range of motion, and moderate to severe disability according to the Neck Disability Index (NDI) will be eligible for inclusion. A total of 38 participants will be enrolled and randomly allocated into two equal groups using sealed opaque envelope randomization performed by a research assistant not involved in the intervention. The study will employ a single-blinded design to minimize assessment bias. Participants allocated to Group A will receive Instrument-Assisted Soft Tissue Mobilization targeting the upper trapezius, levator scapulae, and suboccipital muscles. The intervention will involve systematic identification and treatment of soft tissue restrictions using longitudinal, fanning, and cross-fiber strokes, followed by muscle-specific stretching. Participants allocated to Group B will receive Post Facilitation Stretch directed at the same muscle groups. The PFS protocol will consist of controlled submaximal isometric contractions followed by passive stretching to reduce muscle tightness, restore muscle length, and improve flexibility. Both groups will also receive conventional physiotherapy consisting of hot pack application and transcutaneous electrical nerve stimulation (TENS). Treatment will be administered three times per week for two consecutive weeks, resulting in six treatment sessions for each participant. Standardized treatment protocols will be followed to ensure consistency throughout the study. Pain intensity will be assessed using the Numeric Pain Rating Scale (NPRS), cervical mobility will be measured using the Cervical Range of Motion (CROM) instrument, and functional disability will be evaluated using the Neck Disability Index (NDI). Outcome assessments will be performed at baseline, after the third treatment session, and following completion of the two-week intervention period. Appropriate statistical methods will be applied according to the distribution of the collected data, with statistical significance established at a p-value of less than 0.05. The study will compare both within-group and between-group changes in pain, cervical range of motion, and disability to determine the relative effectiveness of the two interventions. Ethical approval will be obtained from the Ethical Review Committee of Foundation University before commencement of the study. Written informed consent will be obtained from all participants after they have received comprehensive information regarding the study objectives, procedures, potential benefits, and their rights. Participation will be entirely voluntary, and participants will have the right to withdraw from the study at any stage without affecting their routine care. Confidentiality and anonymity of participant information will be maintained throughout the research process, and all collected data will be used exclusively for research purposes. The findings of this randomized controlled trial are expected to provide valuable evidence regarding the comparative effectiveness of Instrument-Assisted Soft Tissue Mobilization and Post Facilitation Stretch in the management of chronic neck pain. The results may assist physiotherapists in selecting the most appropriate manual therapy intervention to reduce pain, improve cervical range of motion, decrease disability, and optimize rehabilitation outcomes. Furthermore, because comparable randomized controlled trials on these interventions have not been conducted in Pakistan according to the study rationale, this research may contribute to the national evidence base and support the development of evidence-based clinical practice guidelines for the rehabilitation of individuals with chronic neck pain.