Quantification of Upper Trapezius Muscle Stiffness Using Supersonic Shear Wave Imaging: Efficacy of Workplace-based Exercise Programme to Reduce Neck and Shoulder Disorders in Working Population

Objectives: (1) To examine the upper trapezius muscle stiffness using SSI in workers with and without neck/shoulder disorders; and (2) to develop a workplace-based exercise programme to reduce upper trapezius muscle stiffness and to enhance shoulder function and work ability in the working population. Hypotheses to be tested: (1) Workers with neck/shoulder disorders demonstrate increase upper trapezius muscle stiffness when compared to healthy control; and a cutoff value of the upper trapezius stiffness was established for early identification of individuals at risk of having neck/shoulder disorders in the working population; (2) Workplace-based exercise programme can reduce upper trapezius muscle stiffness and enhance shoulder function and work ability in the working population. Design: Part A study: Cross-sectional study; Part B study: randomized controlled trial Subjects: One-hundred office computer workers with or without neck/shoulder pain Study instruments: Supersonic shear wave imaging Main outcome measures: Upper trapezius muscle stiffness, Shoulder Pain and Disability Index (SPADI), Neck Disability Index, Disability of the Arm, Shoulder and Hand (DASH), work ability index (WAI). Data analysis: Between-group comparisons to show differences in the outcome measures will be analyzed using Independent t-test. To compare the treatment effects, repeated-measures analysis of variance test (between-group factor: intervention vs control; within-subject factor: time (baseline, 6 week and 1 year)). Expected results: Workers with neck/shoulder disorders demonstrate increase upper trapezius muscle stiffness when compared to healthy control. Workplace-based exercise programme can reduce upper trapezius muscle stiffness and enhance shoulder function and work ability in the working population.