DETERMINATION OF CONTRACTION-INDUCED CHANGES IN ELBOW FLEXOR CROSS-SECTIONAL AREA FOR EVALUATING MUSCLE SIZE-STRENGTH RELATIONSHIP DURING CONTRACTION
DETERMINATION OF CONTRACTION-INDUCED CHANGES IN ELBOW FLEXOR CROSS-SECTIONAL AREA FOR EVALUATING MUSCLE SIZE-STRENGTH RELATIONSHIP DURING CONTRACTION
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DOI：
10.1519/jsc.0000000000000793
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发表时间：
2015-06-01
影响因子：
3.2
通讯作者：
Kawakami, Yasuo
中科院分区：
文献类型：
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作者：
Akagi, Ryota;Iwanuma, Soichiro;Kawakami, Yasuo
本研究的目的是确定收缩引起手肘屈肌横截面积（CSA）的变化，并检查在高强度收缩期间的最大CSA是否比休息时手肘屈肌的强度更密切相关。14名年轻男性受试者参加了这项研究。在参考部位近端1 cm至远端6 cm的部位测量手肘屈肌CSA（从肩胛骨肩峰到肱骨外上髁的上臂长度的60%）（每隔1厘米; 8个采样部位），在休息时和在等长屈肘的最大随意收缩（MVC）的10、20、40、60和80%期间使用磁共振成像。手肘肌CSA在低强度收缩时变化较大，超过60%MVC时变化较小。与静息状态相比，收缩状态下屈肘肌肌腹周围CSA增大，手肘肌远端CSA减小。MVC强度与静息时和各收缩水平的最大CSA显著相关，但逐步多元回归分析仅选择80%MVC期间的最大CSA作为估计MVC强度的显著贡献者。这些结果表明，在手肘屈肌，收缩引起的CSA的变化达到高峰下的高收缩水平和最大CSA在80%MVC更密切相关的MVC强度比在休息。
The aims of this study were to determine contraction-induced changes in the elbow flexor cross-sectional area (CSA) and to examine whether the maximal CSA during a high-intensity contraction is more closely related to the strength than that at rest in the elbow flexors. Fourteen young male subjects participated in this study. The elbow flexor CSAs were measured at sites from 1 cm proximal to 6 cm distal to the reference site (60% of the upper arm length from the acromial process of the scapula to the lateral epicondyle of the humerus) (every 1 cm; 8 sampling sites) using magnetic resonance imaging, at rest and during 10, 20, 40, 60, and 80% of maximal voluntary contraction (MVC) of isometric elbow flexion. The elbow flexor CSA changed greatly during low-intensity contractions, and this contraction-induced change was small over 60% MVC. Compared with at rest, greater CSA around the muscle belly and smaller CSA in the distal portion of the elbow flexors were found in contracted conditions. The MVC strength was significantly correlated with the maximal CSAs at rest and each contraction level, but stepwise multiple regression analysis selected only that during 80% MVC as a significant contributor for estimating the MVC strength. These results suggest that, in the elbow flexors, the contraction-induced change in the CSA reaches its peak under high contractile level and that the maximal CSA during 80% MVC is more closely related to the MVC strength than that at rest.