Determination of muscle fatigue of operating theatre staff using myotonometric measurements.

BACKGROUND: In Latvia, more than 31,000 surgical operations were performed in hospitals in 2023, and work-related musculoskeletal disorders represent one of the most common occupational health problems among healthcare workers. The increasing number of surgeries and the shortage of healthcare personnel in Latvia have led to a higher physical workload among operating theatre staff. This increased workload contributes to muscle fatigue and elevates the risk of work-related musculoskeletal disorders. The aim of this study was to assess changes in muscle frequency and stiffness in order to determine muscle fatigue during the working shift in operating theatre staff using myotonometric measurements. METHODS: Myotonometric measurements were performed at the beginning and end of the work shift using the MyotonPRO device. Muscle frequency and stiffness were assessed bilaterally in selected superficial muscles of the neck, upper limbs, and lower limbs. The study sample consisted of 55 operating theatre employees from two hospitals, representing different occupational roles within surgical and endoscopy departments, and results were analysed according to occupational role, age group, body side, and pre- and post-work shift. RESULTS: Work-shift related increases in muscle frequency and stiffness were observed in the m. trapezius and m. flexor carpi radialis, indicating elevated muscle tension in the neck, shoulder, and forearm regions associated with combined static postures and repetitive upper-limb activity during the working day. These changes were most pronounced among anaesthesia nurses and endoscopy department staff. Statistically significant differences were found between occupational and age groups and between the left and right sides of the body, reflecting task-specific and uneven musculoskeletal loading related to occupational demands. CONCLUSIONS: Myotonometric measurements revealed work-shift-related increases in muscle frequency and stiffness, particularly in the neck and forearm muscles, reflecting muscle fatigue associated with occupational demands in operating theatre staff.