Calcium sensitivity of human single muscle fibers following plyometric training
Calcium sensitivity of human single muscle fibers following plyometric training
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DOI：
10.1249/01.mss.0000232022.21361.47
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发表时间：
2006-11-01
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影响因子：
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通讯作者：
Theisen, Daniel
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文献类型：
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作者：
Malisoux, Laurent;Francaux, Marc;Theisen, Daniel
目的：研究增强式训练对 Ca2+ 敏感性的影响以及肌钙蛋白 T (TnT) 亚型对带皮人体肌肉纤维中 Ca2+ 激活特性的影响。方法：在训练前后对八名男子的股外侧肌进行了活检。对化学结皮纤维的 Ca2+ 激活特性进行了评估，并根据其肌球蛋白重链 (MHC) 含量进行了分类，并对其慢速和快速 TnT 亚型进行了分析。结果：训练后，静态跳、反向跳、6 x 5 米往返跑测试和压腿表现均有显着改善（P < 0.05）。观察到 IIa 型纤维的比例增加了 8% (P < 0.05)。 I 型单纤维直径增加了 11% (P < 0.01)，IIa 型单纤维直径增加了 10% (P < 0.001)，IIa/IIx 型纤维单纤维直径增加了 15% (P < 0.001)。 I 型纤维的峰值纤维力增加了 35% (P < 0.001)，IIa 型纤维增加了 25% (P < 0.001)，IIa/IIx 型纤维增加了 57% (P < 0.01)。 Ca2+激活阈值并未因训练而改变，但引起半最大激活所需的Ca 21 浓度呈下降趋势，其中I型纤维发生显着变化（P < 0.001）。 I 型和 IIa/IIx 型纤维在低 Ca2+ 浓度下的协同性增加 (P < 0.05)。 I 型纤维专门表达慢 TnT 同工型，而 II 型纤维始终与快 TnT 同工型相关，与训练状态无关。因此，训练后 Ca2+ 敏感性的变化不能用差异快或慢的 TnT 同种型表达来解释。结论：增强式训练增加了单纤维 Ca2+ 敏感性，尤其是 I 型纤维。这些变化无法用修改后的 TnT 同工型表达模式来解释。
Purpose: To study the effect of plyometric training on Ca2+ sensitivity and the influence of troponin T (TnT) isoforms on Ca2+-activation properties in skinned human muscle fibers. Methods: Biopsies were obtained from the vastus lateralis of eight men before and after the training period. Chemically skinned fibers were evaluated regarding their Ca2+-activation properties and were classified according to their myosin heavy chain (MHC) contents and analyzed regarding their slow and fast TnT isoforms. Results: After training, significant improvements (P < 0.05) were found for static jump, countermovement jump, 6 x 5-m shuttle-run test, and leg-press performances. An 8% increase in the proportion of type IIa fibers (P < 0.05) was observed. Single-fiber diameters increased by 11% in type I (P < 0.01), 10% in type IIa (P < 0.001), and 15% in type IIa/IIx fibers (P 0.001). Peak fiber force increased by 35% in type I (P < 0.001), 25% in type IIa (P < 0.001), and 57% in type IIa/IIx fibers (P < 0.01). The Ca2+-activation threshold was not altered by training, but the Ca 21 concentration required to elicit half-maximal activation showed a decreasing trend, with significant changes in type I fibers (P < 0.001). Cooperativity at low Ca2+ concentrations was increased in type I and type IIa/IIx fibers (P < 0.05). Type I fibers exclusively expressed slow TnT isoforms, and type II fibers were always associated with fast TnT isoforms, independent of training status. Therefore, changes in Ca2+ sensitivity after training could not be explained by differential fast or slow TnT isoform expression. Conclusion: Plyometric training increased single-fiber Ca2+ sensitivity, especially in type I fibers. These changes could not be explained by a modified TnT isoform expression pattern.