【論文摘要】The Musculotendinous Architecture of Supraspinatus: The Effects of Muscle Length and Strength

【論文摘要】棘上肌之肌肉肌腱結構於不同肌肉長度下之變化及與肌力之關係

周彥菱(Yen-Ling Chou) ； 林燕慧(Yang-Hua Lin) ； 陳柏村(Po-Tsun Chen)

《物理治療》 47卷4期 (2022/12) Pp. 279-280

https://doi.org/10.6215/FJPT.202212.O02

摘要

Background and Purpose: Supraspinatus stiffness is commonly occurred after tendon repairing surgery and becoming a disturbance during rehabilitation. To monitor the length changes during exercise is critical to avoid overstretching and re-tearing the tendon. However, there was no evidence relating to the musculotendinous architecture (MA) changes of supraspinatus after stretching. Hence, this study aimed to compare the changes of MA of supraspinatus between the lengthening and contraction conditions as well as the correlation with muscle strength. Methods: Eight healthy participants were recruited for the sonographic evaluation of supraspinatus MA. The MA, including the fiber bundle length (FBL) and pennation angle (PA), were measured at resting posture, 30° abduction, 30° abduction with external weight of 5 lb and stretching status (maximum internal rotation at maximum horizontal abduction with 90° elevation). The supraspinatus strength was measured by full-can test at scaption 90° with elbow extension, and shoulder neutral rotation. The Friedman's test with Wilcoxon signed-rank test as post hoc test were used to compare the MA between difference conditions. The Spearman's rank correlation test was used to analyze the association between MA and supraspinatus strength (full-can). Results: The FBL during stretching status (4.49 ± 0.75 cm) was significantly longer than the other conditions, followed by resting posture (4.06 ± 0.59 cm), 30° abduction without (3.47 ± 0.74 cm) and with external weight (3.12 ± 0.81 cm). The largest PA was significantly found during 30° abduction with weight (16.81° ± 1.73°) and followed by 30° abduction without weight (13.30° ± 1.84°), resting posture (10.95° ± 1.22°) and stretching (9.53° ± 1.20°). The significant correlations were noticed between the maximal strength of supraspinatus regarding to the FBL during all conditions (r_s = 0.762-0.810, p ＜ 0.05) as well as the PA during 30° abduction (r_s = 0.738, p = 0.037). Conclusion: Significant changes in MA of supraspinatus were observed during different conditions in healthy subjects. The patients with rotator cuff related disorder should be evaluated for the altered MA in the future. Clinical Relevance: The normal value of MA changes across various conditions may be used as a reference for evaluating the musculotendinous dysfunction of supraspinatus.