Effect of Cervical Force Control Training on Force Sense and Steadiness in Chronic Non-Specific Neck Pain

Effect of Cervical Force Control Training on Force Sense and Steadiness in Chronic Non-Specific Neck Pain

Chronic non-specific neck pain (CNSNP) is a very common issue among young adults, often linked to poor posture, prolonged screen time, and sedentary habits. This persistent pain can change how the neck muscles work and control movement. The purpose of this study is to investigate whether a specific type of rehabilitation-called "cervical force control training"-can help improve how well people can feel and control their neck muscle strength, and whether this reduces their pain and improves their daily function.

Researchers will invite young adults (18 to 24 years old) who have had neck pain for at least 3 months to participate. Participants will be randomly divided into two groups:

Force Control Training Group: Will receive a new training program that uses a handheld dynamometer with a screen to help them practice holding steady, precise neck muscle contractions with visual feedback.

Conventional Exercise Group: Will receive a standard physical therapy program consisting of neck muscle stretches and shoulder-blade strengthening exercises.

Both groups will perform their exercises 3 times a week for 8 weeks. Researchers will measure participants' neck muscle steadiness, pain levels, and neck disability before the program starts, right after the 8-week program ends, and again at a 3-month follow-up to evaluate the long-lasting effects.

Chronic non-specific neck pain (CNSNP) involves persistent cervical pain without an identifiable structural pathology. Recent evidence suggests that CNSNP is closely associated with sensorimotor control deficits, including impaired proprioception and diminished force steadiness (the neuromuscular ability to produce and sustain precise submaximal force levels with minimal fluctuations). While conventional exercises improve strength and reduce pain, they often neglect the fine-motor precision and sensorimotor integration necessary for optimal neck function.

This randomized controlled trial (RCT) is designed to investigate the effect of cervical force control training compared to conventional neck exercises on force sense, force steadiness, pain intensity, and functional disability in young adults (18-24 years) with CNSNP.

Following baseline assessments for maximum voluntary isometric contraction (MVIC), force sense, and force steadiness (quantified by the coefficient of variation) using a Handheld Dynamometer (HHD), as well as clinical measures (VAS for pain, NDI for disability), eligible participants will be randomized into two groups:

Experimental Group (Force Control Training):

Participants will undergo an 8-week targeted training program (3 sessions/week, 30-40 mins each). The protocol utilizes submaximal isometric contractions with visual feedback via an HHD device paired with an application. The program progresses systematically through three phases: Phase 1 (Calibration & Reference at MVIC), Phase 2 (Acquisition using descending submaximal intensities 25% to 10% MVIC with continuous visual tracking), and Phase 3 (Retention & Transfer involving faded/no feedback and complex dual-tasking, such as auditory monitoring or arithmetic).

Control Group (Conventional Exercise Training):

Participants will undergo an 8-week program (3 sessions/week, 30 mins each) consisting of standard cervical stretching (upper trapezius and levator scapulae) and scapular strengthening/stabilization exercises (e.g., side-lying external rotation, side-lying forward flexion, prone extension, and push-up plus). Resistance will be tailored based on gender and body weight.

Re-evaluations will be conducted immediately post-intervention (at 8 weeks) and at a 3-month follow-up. The study aims to establish whether integrating specific force-control tasks offers superior benefits in restoring sensorimotor function and alleviating symptoms in patients with CNSNP compared to conventional rehabilitation alone.

Inclusion Criteria:

• Patients diagnosed with Chronic Non-Specific Neck Pain (CNSNP) lasting >= 3 months.
• Body mass index (BMI) between 18.5 and 29.9 kg/m² (non-obese).
• Pain intensity >= 30 mm on the Visual Analogue Scale (VAS).
• Neck disability ranging from mild to moderate (10% to 48%) on the Neck Disability Index (NDI).
• Able to perform isometric contractions with visual feedback.

Exclusion Criteria:

• Shoulder/upper limb fractures or replacement (<12 months), or moderate-severe shoulder osteoarthritis (OA).
• Cervical radiculopathy/myelopathy, peripheral neuropathy, vestibular disorders, or history of stroke/Transient Ischemic Attack (TIA).
• Upper limb pathology (tendinopathy, capsulitis), thoracic outlet syndrome, or fibromyalgia.
• Received neck-specific physiotherapy within the last 3 months.
• Severe osteoporosis, uncontrolled diabetes (HbA1c >9%), or active infection/inflammation.
• Cervical injections or surgery within the last 6 months.
• Inability to follow 2-step instructions.