人类小腿三头肌肌纤维型分布

The Distribrtion of Fiber Types in Human m. Triceps Surae

本研究为查清小腿三头肌各部肌纤维型的分布特征和构成比。结果表明,腓肠肌内,外侧头各亚部两型肌纤维呈棋盘格式分布,Ⅰ型纤维比例占58％左右。有两例外侧头肌质亚部和浅亚部Ⅱ型纤维占优势,统计学上有显著性差异。这提示个体间肌纤维型比例存在较大差异,鉴于腓肠肌内、外侧头肌纤维的分布和肌构筑特征,作者推测,腓肠肌内侧头在直立负荷和提跟运动中能提供足够的肌力,外侧头主要参与速度运动。比目鱼肌主部的Ⅰ型纤维占82.4％,比目鱼肌副肌束占65.9％,低于主部Ⅰ型纤维比例。副肌束的肌纤维型分布特点和功能、起源有待进一步研究。在小腿三头肌,比目鱼肌拥有80％以上的Ⅰ型纤维,而腓肠肌两型纤维几乎各占一半。作者认为这种特点使小腿三头肌主要起支持和稳定人体姿势的作用,在需要力量和速度时,也能提供人类在走、跑、跳运动中的推进动力。

The fiber types composition in human m. triceps surae is investigated. The medial and lateral gastrocnemius contains 57.9％ and 57.3％ type Ⅰ fibers respectively and shows a mosaic pattern of fiber types distrioution. The most interesting finding is that the proportion of type Ⅱ fiber of both medial and (?)ateral compartments of the lateral gastro cnemius in two individuals is significantly higher than those of the ofters. According to their architecture and also their fiber types composition the authors suggeste that the medial gastrocnumius is designed producing relative high tension in maintaining the vertical posture and elevating the calcaneus when standing and walking,and elevating the lateral gastrocnum us is designed to serve more in velocity of shortening. The main portion of the soleus and its aecessory fasciculus contain 82.4％ and 65.9％ type Ⅰ fiber respectively. More information on the accessory fascieulus of the soleus, the fiber type distribution, function and phylogenetic origin, is still needed,The fiber types composition of the m. triceps surae indicate that in addition to maintaining the upright postere,the m. triceps surae seem to take more part in walking running and jumping as a propelling force.