The effect of the muscular training on joint laxity and muscle extensibility

一般来说，适当的关节刚度被认为可以防止受伤和改善身体活动。在这项研究中，我们的目的是阐明肌肉训练对关节松弛和肌肉伸展性的影响。首先，我们建立了评价关节松弛的动物模型。然后，我们研究了急性和慢性运动的效果。主要研究结果如下：1.首次研制了大鼠踝关节柔韧性评价装置。2.通过使用我们开发的装置，我们发现成年大鼠踝关节的松弛度低于年轻大鼠，这与人类研究中的报道一致。3.我们还发现了人类研究中大鼠踝关节松弛度的性别差异。腓肠肌伸展性和连接素亚型的组成也有所增加。4.对大鼠腓肠肌进行一次延长性收缩试验，可降低大鼠踝关节的柔韧性，增加大鼠腓肠肌的伸展性。我们也 ...更多信息 证实暴露的腓肠肌的被动张力显著高于未处理的对照。两组的肌肉湿重相同，表明没有水肿。有趣的是，这种现象只出现在年轻大鼠。5.我们研究了重复离心运动（20天）对大鼠腓肠肌踝关节僵硬度和titin（连接蛋白）亚型组成的影响。长时间离心运动后，腓肠肌内侧肌湿重显著增加。肌球蛋白-ATP酶染色显示IIB型纤维百分比下降，IIA型纤维百分比增加。我们发现，离心运动组的踝关节僵硬度显著小于假手术等长训练组。综上所述，我们得出结论，长期离心运动增加肌肉力量和关节松弛。我们现在认为，长期离心运动是独特的，应该是有益的调节和预防运动相关损伤。少

In general, the appropriate joint stiffness has been regarded to prevent injuries and improve physical activities. In this study, we aimed to elucidate the effects of the muscular training on joint laxity and muscle extensibility. At first, we developed the animal models to evaluate joint laxity. Then, we examined the effect of acute and chronic exercise. The obtained results are summarized as follows ;1.We firstly developed the device to evaluate the flexibility of rat ankle joint. This house-made2.By using our developed device, we found that adult rat ankle joint showed lower laxity in comparison to young rat as reported in human studies.3.We also found the gender differences in rat ankle joint laxity as reported in human studies. The gastrocnemius muscle extensibility and connectin isoform compositions also differed.4.A bout of lengthening contractions on rat gastrocnemius muscle tentatively decreased rat ankle joint flexibility and increased rat gastrocnemius extensibility. We also … More confirmed that the passive tension of the exposed gastocnemius was significantly higher than that of the non-treated control. The muscle wet weights were identical in both groups, suggesting that the absence of edema. Interestingly, this phenomenon was only seen in young rats.5.We investigated the effects of repeated eccentric exercise (20 days) for rat gastrocnemius muscle on ankle joint stiffness and titin (connectin) isoform composition. After the prolonged eccentric exercise, the wet weight of medial gastrocnemius muscle significantly increased. Myosin-ATPase staining showed a decrease in the percentage of type IIB fibers and an increase in the percentage of type IIA fibers. We found that the ankle joint stiffness was significantly smaller in eccentric-exercise group than in sham-operated isometoric trained group. Above all, we conclude that chronic eccentric exercise increase both muscular strength and joint laxity.We are now considering that the prolonged eccentric exercise posses peculiar and should be useful for conditioning and prevention for sport-related injuries. Less