Reproducibility of subscapularis muscle thickness measurement using ultrasound imaging. -Relationship between subscapularis muscle thickness and internal rotation torque of the shoulder joint

• Published in: Journal of bodywork and movement therapies 2023-10, Vol.36, p.349-356
• Main Authors: Homma, Hisashi, Aoki, Mitsuhiro, Okino, Kumiko, Hayashi, Tomoya, Yamane, Masahiro, Sasaki, Yuji
• Format: Article
• Language: English
• Subjects: Bland–altman analysis; Internal rotation torque; Intra-inter-rater reproducibility; Muscle thickness measurement; Subscapularis muscle; Ultrasound imaging
• ISSN: 1360-8592; 1532-9283
• DOI: 10.1016/j.jbmt.2023.09.003

Few studies have reported on the morphometry of the subscapularis muscle using ultrasound imaging (USI); and their reproducibility has not been verified. This study aimed to clarify the relative and absolute reproducibility of USI measurements of subscapularis muscle thickness at rest and during isometric contraction as well as the degree of change in muscle thickness caused by the amount of internal rotational torque in the shoulder joint. Two-group repeated-measures study. The subjects were the inferior fibers of the subscapularis muscle of 40 healthy adult males. Muscle thickness was measured at rest and at 10%–30% of the maximum isometric internal rotation torque. Intraclass correlation coefficients (ICC) and Brand Altman analysis were used for reproducibility measurement. The degree of change in muscle thickness at each torque was also calculated. Intra- and inter-rater ICCs (ranged from 0.69 to 0.91) were good. A proportional error was observed in intra-rater measurements. Both minimal detectable change 95 (ranged from 2.33 to 6.47) were high. The subscapularis muscle thickness was significantly increased at 10% torque (25.49 ± 3.80 mm), 20% torque (26.07 ± 3.90 mm), and 30% torque (25.96 ± 3.82 mm) as compared to that in resting conditions (24.53 ± 4.46 mm) (p