Sugisaki Norihide, Wakahara Taku, Murata Koichiro, Miyamoto Naokazu, Kawakami Yasuo, Kanehisa Hiroaki, Fukunaga Tetsuo
Center for Environment, Health and Field Sciences, Chiba University, Kashiwa-no-ha, Kashiwa, Chiba, Japan.
J Appl Biomech. 2015 Apr;31(2):111-6. doi: 10.1123/jab.2014-0126. Epub 2014 Nov 20.
Although the moment arm of the triceps brachii muscle has been shown to be associated with the muscle's anatomical cross-sectional area, whether training-induced muscle hypertrophy alters the moment arm of the muscle remains unexplored. Therefore, the current study aimed to examine this. Eleven men underwent a 12-week resistance training program for the triceps brachii muscle. The maximum muscle anatomical cross-sectional area (ACSAmax), the moment arm of the triceps brachii muscle, and the anterior-posterior dimension of the olecranon were measured using a magnetic resonance imaging system before and after intervention. The ACSAmax (33.6 ± 11.9%, P < .001) and moment arm (5.5 ± 4.0%, P = .001) significantly increased after training, whereas the anterior-posterior dimension of the olecranon did not change (P > .05). The change in moment arm was smaller than that expected from the relationship between the ACSAmax and the moment arm before the intervention. The present results indicate that training-induced triceps brachii muscle hypertrophy could increase the muscle moment arm, but its impact can be small or negligible.
尽管已证明肱三头肌的力臂与该肌肉的解剖横截面积相关，但训练引起的肌肉肥大是否会改变该肌肉的力臂仍未得到探索。因此，本研究旨在对此进行检验。11名男性参与了一项针对肱三头肌的为期12周的阻力训练计划。在干预前后，使用磁共振成像系统测量肱三头肌的最大肌肉解剖横截面积（ACSAmax）、肱三头肌的力臂以及尺骨鹰嘴的前后径。训练后，ACSAmax（33.6±11.9%，P<.001）和力臂（5.5±4.0%，P=.001）显著增加，而尺骨鹰嘴的前后径未发生变化（P>.05）。力臂的变化小于干预前ACSAmax与力臂之间关系所预期的变化。目前的结果表明，训练引起的肱三头肌肥大可增加肌肉力臂，但其影响可能较小或可忽略不计。
