PhD Oral Exam - Alireza Derakhshani, Health and Exercise Science

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

Neck and shoulder pain is the most frequently reported musculoskeletal complaint among computer workers and a common cause of work disability. It has long been linked to the muscle activation pattern of computer work, which combines low-level and continuous activity with insufficient muscular rest, particularly in the upper trapezius and the cervical paraspinal muscles. Two strategies are commonly proposed to modify this pattern: interrupting the task with short passive or active pauses, and strengthening the neck and shoulder muscles through exercise. Past findings suggest that exercise improves pain and disability in these workers, and that pauses can alter muscle activation, but most evidence on pauses comes from workers without symptoms and the results are contradictory. In addition, surface electromyography describes muscle recruitment but not the mechanical state of the tissue, and psychological factors such as pain catastrophizing and fear-avoidance beliefs are rarely measured alongside muscle outcomes. Whether these interventions change muscle behavior in workers who already have pain, and whether such a change is needed for clinical improvement, therefore remains unclear. This five-chapter dissertation aimed to investigate the effect of two interventions on muscle activation, muscular rest, neck disability, and psychological outcomes, and the relationship between muscle stiffness and activation, in computer workers with neck and shoulder pain. Chapter 1 reviews the literature and sets out the rationale, objectives, and hypotheses. Chapter 2 aimed to compare passive, static active, and dynamic active pauses integrated into a simulated computer task, and their effect on muscle activation, muscular rest, and perceived exertion. Chapter 3 aimed to investigate the effect of a six-week home-based upper body training program on muscle activation, muscular rest, neck disability, pain catastrophizing, fear-avoidance beliefs, and perceived exertion, and the association between muscle activation and self-reported outcomes. Chapter 4 aimed to examine, using shear wave elastography, the association between resting upper trapezius stiffness and muscle activation during a prolonged simulated computer task, and the relationship of both stiffness and muscle activation with psychological and clinical measures. Chapter 5 integrates the results of Chapters 2 to 4 and states the general limitations, implications, recommendations for future research, and conclusions.