ATP economy of force maintenance in human tibialis anterior muscle
ATP economy of force maintenance in human tibialis anterior muscle
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DOI：
10.1249/01.mss.0000166946.94871.9b
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发表时间：
2005-06-01
期刊：
影响因子：
--
通讯作者：
Quistorff, B
中科院分区：
文献类型：
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作者：
Nakagawa, Y;Ratkevicius, A;Quistorff, B
目的：本研究的目的是探讨在60 s的无氧随意收缩在50%的最大随意收缩（MVC）的力量维持在人类胫骨前肌ATP经济。方法：采用31 p磁共振波谱（P-31-MRS）技术检测脑组织ATP转换率.踝背屈肌的总体积通过H-1磁共振成像（MRI）（H-1-MRI）进行评估，胫骨前肌的纤维类型组成通过肌肉活检组织化学分析进行评价。结果：胫前肌占踝背屈肌总体积的59.7 ± 0.6%（平均值± SEM），踝背屈肌总体积为267 ± 10 cm（3）。胫骨前肌中1型、IIA型和IIB型纤维所占的相对横截面积分别为69.3 +/- 2.2、27.4 +/- 2.76和3.2 +/-1.0%。在60年代的收缩中，ATP部队维持的经济性没有显著变化。平均为4.8 ± 0.42 N（.）s（.）μ mol（-1），并与I型肌纤维所占的相对横截面积相关（r = 0.73，P < 0.01）。在收缩的后半部分，力量下降的受试者表现出较低的ATP经济性（3.7 +/- 0.6 vs 5.3 +/- 0.6 N（.）s（.）μ mol（-1）; P < 0.05）。结论：有人认为，在自愿收缩过程中保持不变的ATP经济力可能是由于增加ATP经济的收缩肌纤维抵消了温度升高和低ATP经济的11型纤维的影响。运动单元之间的机械相互作用也可以起到改善ATP部队维持经济性的作用。
Purpose: The aim of this study was investigate ATP economy of force maintenance in the human tibialis anterior muscle during 60 s of anaerobic voluntary contraction at 50% of maximum voluntary contraction (MVC). Methods: ATP turnover rate was evaluated using 3 1 p magnetic resonance spectroscopy (P-31-MRS). The total volume of ankle dorsiflexor muscles was assessed by H-1 magnetic resonance imaging (MRI) (H-1-MRI), and the fiber type composition of the tibialis anterior muscle was evaluated using histochemical analysis of muscle biopsies. Results: The tibialis anterior muscle occupied 59.7 +/- 0.6% (mean +/- SEM) of the total ankle dorsiflexor muscle volume, which was 267 10 cm(3). Relative cross-sectional areas occupied by Type 1, IIA, and IIB fibers in the tibialis anterior were 69.3 +/- 2.2, 27.4 +/- 2.76, and 3.2 +/- 1.0%, respectively. ATP economy of force maintenance did not change significantly during the 60-s contraction. It averaged at 4.8 1 0.42 N(.)s(.)mu mol(-1), and correlated with the relative cross-sectional area of the muscle occupied by Type I fiber (r = 0.73, P < 0.01). For the second half of the contraction, subjects dropping in force showed lower ATP economy compared with those maintaining the force (3.7 +/- 0.6 vs 5.3 +/- 0.6 N(.)s(.)mu mol(-1); P < 0.05). Conclusion: It is argued that the unchanged ATP economy of force maintenance during the voluntary contraction could be due to an increase in the ATP economy of contracting muscle fibers offsetting the effects of increased temperature and low ATP economy of Type 11 fibers. Mechanical interaction between motor units could also act to improve ATP economy of force maintenance.