The relationship between trapezius muscle oxygenation, respiratory and peripheral muscle strength, and functional...

Chronic neck pain is a common musculoskeletal disorder associated with functional limitations and reduced activities of daily living. The upper trapezius muscle plays an important role in posture, scapular stabilization, and accessory respiration, and may be affected metabolically in chronic neck pain. This study aimed to investigate the relationship between trapezius muscle oxygenation and respiratory and peripheral muscle strength and functional performance in patients with chronic neck pain.

Fifty-one patients with chronic neck pain (age: 53.4 ± 12.3 years) were included in the study. Muscle oxygenation (Moxy® monitor), maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) (mouth pressure device), peripheral muscle strength (hand-held dynamometer), upper extremity functional exercise capacity (six-minute pegboard and ring test [6-PBRT]), and activities of daily living (ADL) (Glittre ADL test) were evaluated.

The minimum trapezius muscle oxygen saturation (SmO₂) value had a moderate, significant positive correlation with MIP (r = 0.511), MEP (r = 0.522), the 6-PBRT score (r = 0.634), and trapezius muscle strength (r = 0.542), and a moderate, significant negative correlation with Glittre ADL test time (r =  -0.581). It showed weak correlations with shoulder abductor and flexor strength, elbow flexor strength, and handgrip strength (r = 0.30-0.49). The maximum SmO₂ value demonstrated moderate correlations with MIP (r = 0.637), MEP (r = 0.606), and trapezius muscle strength (r = 0.590); strong correlations with the 6-PBRT score (r = 0.718) and Glittre ADL (r =  -0.711) test time; and weak correlations with shoulder abductor and flexor strength, elbow flexor strength, and handgrip strength (r = 0.30-0.49). Changes in SmO₂ during exercise were significantly associated with MIP (β = 0.400, R² = 0.160, p = .004), MEP (β = 0.327, R² = 0.107, p = .019), 6-PBRT score (β = 0.510, R² = 0.260, p < .001), and Glittre ADL test time (β = -0.354, R² = 0.125, p = .011).

Trapezius muscle oxygenation was associated with respiratory muscle strength, upper extremity exercise capacity, and activities of daily living. These findings suggest that trapezius muscle oxygenation may provide insight into underlying physiological mechanisms related to respiratory and functional impairment.