Muraoka Tetsuro, Muramatsu Tadashi, Fukunaga Tetsuo, Kanehisa Hiroaki
Laboratory of Sports Sciences, Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan.
Cells Tissues Organs. 2004;178(4):197-203. doi: 10.1159/000083731.
The purpose of this study was to clarify whether the major determinant of the extendibility of the Achilles tendon in young adults was the geometric properties of the tendon. The subjects were 38 healthy young adults (26 male, 12 female; 26 +/- 5 years). The subjects developed maximum voluntary isometric plantar flexion (MVIP) torque while the displacement of the distal myotendinous junction of the medial gastrocnemius and ankle joint rotation was determined using a B-mode ultrasonograph and a goniometer, respectively. The tendon force (F) was calculated from MVIP torque and the moment arm of Achilles tendon. The elongation of the Achilles tendon (delta X) was obtained from the tendon displacements and ankle joint rotation. Achilles tendon stiffness (k) was calculated by dividing F by delta X. The specific stiffness of the Achilles tendon (k(s)) was obtained from k normalized to the Achilles tendon length at rest. The cross-sectional area of the Achilles tendon (CSA) was measured at 5, 10, and 15% of the lower leg length proximal to the insertion of the Achilles tendon using a B-mode ultrasonography. The results showed that more distal portion of the Achilles tendon had a larger CSA, and that there was a strong correlation between the average and minimum Achilles tendon CSA. delta X was 9.9 +/- 2.5 mm. k and k(s) were 330 +/- 77 N/mm and 63 +/- 20 kN, respectively. No significant correlation was seen between CSA and k(s) (r = 0.15, p > 0.05). It was suggested that a stiffer Achilles tendon did not necessarily have a thicker shape, which might indicate that the major determinant of the extendibility of the Achilles tendon was not its geometric properties in young adults.
本研究的目的是阐明在年轻成年人中，跟腱伸展性的主要决定因素是否为肌腱的几何特性。研究对象为38名健康的年轻成年人（26名男性，12名女性；年龄26±5岁）。研究对象进行最大自主等长跖屈（MVIP）时，分别使用B型超声仪和角度计测定腓肠肌内侧头远端肌腱结合处的位移和踝关节旋转。根据MVIP扭矩和跟腱的力臂计算肌腱力（F）。跟腱伸长量（δX）由肌腱位移和踝关节旋转得出。跟腱刚度（k）通过F除以δX计算得出。跟腱的比刚度（k(s)）由静息状态下k除以跟腱长度标准化得到。使用B型超声在跟腱附着点近端小腿长度的5%、10%和15%处测量跟腱的横截面积（CSA）。结果显示，跟腱更靠远端的部分CSA更大，且跟腱平均CSA与最小CSA之间存在强相关性。δX为9.9±2.5毫米。k和k(s)分别为330±77牛/毫米和63±20千牛。CSA与k(s)之间未见显著相关性（r = 0.15，p>0.05）。这表明较硬的跟腱不一定形状更厚，这可能意味着在年轻成年人中，跟腱伸展性的主要决定因素不是其几何特性。
