A comparison of the moment arms of pelvic limb muscles in horses bred for acceleration (Quarter Horse) and endurance (Arab)
A comparison of the moment arms of pelvic limb muscles in horses bred for acceleration (Quarter Horse) and endurance (Arab)
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DOI：
10.1111/j.1469-7580.2010.01241.x
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发表时间：
2010-07-01
影响因子：
2.4
通讯作者：
Payne, R. C.
中科院分区：
文献类型：
--
作者：
Crook, T. C.;Cruickshank, S. E.;Payne, R. C.
对性能的选择性育种导致了不同品种的马，如夸特马（为加速而培育）和阿拉伯马（为耐力而培育）。快速加速，在四分之一马比赛中看到，需要快速有力的肌肉收缩和大关节扭矩的产生，特别是通过后肢肌肉。本研究比较了四分之一马和阿拉伯人的后肢力臂长度。我们假设，四分之一马后肢伸肌相比，阿拉伯人有更长的力臂，赋予更大的潜力，在髋关节，后膝关节和跗骨在肢体伸展扭矩的产生。解剖6只夸特马和6只阿拉伯后肢，以确定以下肌肉的肌肉力矩臂长度：臀中肌、股二头肌、半腱肌、股外侧肌、腓肠肌（内侧肌和外侧肌）和胫骨前肌。四分之一马的股二头肌（作用于髋关节）和腓肠肌外侧（作用于后膝关节）的力矩臂明显较长，尽管两种马的其余肌肉力矩臂的长度相似。所有的四分之一马肌肉能够产生更大的肌肉力矩，由于其更大的生理横截面积（PCSA），因此更大的等长肌力潜力，这表明PCSA是一个更好的决定因素，肌肉扭矩比力矩臂长度在这两个品种的马。除腓肠肌和胫骨颅侧肌外，阿拉伯马肌肉观察到的肌束长度与力臂比（MFL：MA比）更大。看来，阿拉伯肌肉有可能在收缩速度较慢的情况下工作，因此与在类似关节运动范围内工作的四分之一马肌肉相比，产生更大的力输出;这表明阿拉伯后肢肌肉被优化为在最大经济性而不是最大功率输出下发挥作用。
Selective breeding for performance has resulted in distinct breeds of horse, such as the Quarter Horse (bred for acceleration) and the Arab (bred for endurance). Rapid acceleration, seen during Quarter Horse racing, requires fast powerful muscular contraction and the generation of large joint torques, particularly by the hind limb muscles. This study compared hind limb moment arm lengths in the Quarter Horse and Arab. We hypothesized that Quarter Horse hind limb extensor muscles would have longer moment arms when compared to the Arab, conferring a greater potential for torque generation at the hip, stifle and tarsus during limb extension. Six Quarter Horse and six Arab hind limbs were dissected to determine muscle moment arm lengths for the following muscles: gluteus medius, biceps femoris, semitendinosus, vastus lateralis, gastrocnemius (medialis and lateralis) and tibialis cranialis. The moment arms of biceps femoris (acting at the hip) and gastrocnemius lateralis (acting at the stifle) were significantly longer in the Quarter Horse, although the length of the remaining muscle moment arms were similar in both breeds of horse. All the Quarter Horse muscles were capable of generating greater muscle moments owing to their greater physiological cross-sectional area (PCSA) and therefore greater isometric force potential, which suggests that PCSA is a better determinant of muscle torque than moment arm length in these two breeds of horse. With the exception of gastrocnemius and tibialis cranialis, the observed muscle fascicle length to moment arm ratio (MFL : MA ratio) was greater for the Arab horse muscles. It appears that the Arab muscles have the potential to operate at slower velocities of contraction and hence generate greater force outputs when compared to the Quarter Horse muscles working over a similar range of joint motion; this would indicate that Arab hind limb muscles are optimized to function at maximum economy rather than maximum power output.