The aim of this study was to describe the structural and ultrastructural aspects of the myotendinous junction (MTJ) and the proximal and distal sarcomeres of the sternomastoid of aged Wistar rats subjected to an experimental model of menopause and swimming training. A total of 20 female elderly rats were divided into the following four groups (n=5 in each group): sedentary/no-menopausal (SNM), trained/no-menopausal (TNM), sedentary/menopausal (SM), and trained/menopausal (TM). The MTJ samples were dissected and analyzed using transmission electron microscopy. We showed that the TNM Group rats exhibited changes in morphological characteristics as a consequence of physical exercise, which included an increase of 36.60% (P<0.001) in the evagination length of the MTJ and a reduction in the length of the distal (77.38%) (P<0.0001) and proximal (68.15%) (P<0.0001) sarcomeres. The SM Group exhibited a reduction of about 275.93% (P<0.001) in the muscle-tendon interface and in the lengths of distal sarcomeres (55.87%) (P<0.0001) compared with SNM Group. Our results suggest that the swimming training under experimental model of menopause promoted tissue reorganization and increased muscle-tendon interaction with a drastic development in the length and thickness of the sarcoplasmatic invaginations and evaginations. In addition, the sarcomeres exhibited different lengths and a reduction in both groups subjected to swimming training.

中文翻译：

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更年期实验模型中体能训练对颈部肌节长度和肌腱界面的影响。

本研究的目的是描述接受更年期和游泳训练实验模型的老年 Wistar 大鼠的肌腱连接处 (MTJ) 以及胸骨乳突近端和远端肌节的结构和超微结构。将20只雌性老年大鼠分为以下四组（每组n = 5）：久坐/未绝经（SNM）、训练/未绝经（TNM）、久坐/绝经（SM）和训练/更年期（TM）。使用透射电子显微镜对 MTJ 样品进行解剖和分析。我们发现，TNM 组大鼠由于体育锻炼而表现出形态特征的变化，其中包括 MTJ 外翻长度增加 36.60%（P<0.001），远端长度减少（77.38%）。 ）（P<0.0001）和近端（68.15%）（P<0.0001）肌节。与SNM组相比，SM组的肌肉-肌腱界面和远端肌节长度（55.87%）（P<0.0001）减少了约275.93%（P<0.001）。我们的结果表明，更年期实验模型下的游泳训练促进了组织重组，增加了肌肉与肌腱的相互作用，肌浆内陷和外翻的长度和厚度急剧发展。此外，接受游泳训练的两组肌节表现出不同的长度和减少。