Kunimasa Y, Sano K, Oda T, Nicol C, Komi P V, Locatelli E, Ito A, Ishikawa M
Scand J Med Sci Sports. 2014 Aug;24(4):e269-74. doi: 10.1111/sms.12161.
The Achilles tendon moment arm (MA_AT) and foot lever ratio (FLR) can play important roles for force production and movement economy during locomotion. This notion has become more relevant, and suggestion has been given that the Kenyan runners belonging to the world elite would have specific anatomical, mechanical, and functional properties in their lower limbs and that this feature could be responsible for their high running economy. The present study aimed to characterize the AT of elite Kenyan distance runners as compared with Japanese ones, and to examine the potential relationship with their running performance. Ultrasonography was used to measure AT cross-sectional area and AT soleus and gastrocnemius lengths. MA_AT and FLR were calculated from the position of anatomical landmarks using sagittal plane photographs. MA_AT was significantly longer and the FLR lower in Kenyans than in Japanese. Independently of the group, the running performance was positively related to the MA_AT (r = 0.55, P < 0.001) and negatively to the FLR (r = -0.45, P = 0.002). These results suggest that longer MA_AT and lower FLR could be advantageous in elite Kenyan runners, by contributing to effective endurance running performance in a protective and economical way.
跟腱力臂（MA_AT）和足杠杆比（FLR）在运动过程中的力量产生和运动经济性方面可能发挥重要作用。这一概念变得愈发重要，并且有人提出，属于世界精英水平的肯尼亚跑步运动员在其下肢具有特定的解剖学、力学和功能特性，而这一特征可能是他们高跑步经济性的原因。本研究旨在将肯尼亚精英长跑运动员的跟腱与日本运动员的跟腱进行特征描述，并探讨其与跑步成绩的潜在关系。使用超声测量跟腱横截面积以及跟腱比目鱼肌和腓肠肌长度。利用矢状面照片从解剖标志点的位置计算MA_AT和FLR。肯尼亚人的MA_AT明显长于日本人，而FLR则低于日本人。不考虑组别，跑步成绩与MA_AT呈正相关（r = 0.55，P < 0.001），与FLR呈负相关（r = -0.45，P = 0.002）。这些结果表明，更长的MA_AT和更低的FLR可能对肯尼亚精英跑步运动员有利，通过以一种保护性和经济性的方式有助于有效的耐力跑步成绩。
