The Effect of Low-load Endurance Training of Upper Trapezius on Pain, Pressure Pain and Muscle Stiffness in Chronic Neck-shoulder Pain Compared to Stretching Exercise

This study aims to investigate the effectiveness of low-load endurance exercise as compared to stretching exercise on upper trapezius on pain, pressure pain and muscle stiffness in patients with chronic neck-shoulder pain. The hypothesis is that endurance exercise of the upper trapezius should result in significantly better improvement in terms of neck-shoulder pain, pressure pain threshold and muscle stiffness than stretching exercise. Participants with unilateral neck-shoulder pain will either perform low-load endurance exercise or stretching exercise of the upper trapezius muscle of the affected side in a 5-week period. Before and after the 5-week training, outcomes will be assessed by investigators in order to compare the effectiveness of two exercises on pain, pressure pain, muscle stiffness, and muscle endurance. Secondary outcomes include Neck Disability Index (NDI) to assess various aspects of daily living impacted by neck pain, and Disabilities of Shoulder, Arm and Hand (DASH) Questionnaire to evaluate the ability to perform various upper limb activities. Findings to be obtained from this study will help inform the clinical management in particular for self-care of this chronic neck pain group of participants, by refining the exercise prescription for promoting the clinical outcomes for individuals suffering from neck-shoulder pain. In addition, results of this study will also inform physiotherapists the possible mechanisms underlying the improvement of neck-shoulder pain by examination of the relationship between biomechanical properties of muscles, such as muscle endurance or muscle stiffness, and neck-shoulder pain.