Usherwood James R, Wilson Alan M
Structure and Motion Laboratory, The Royal Veterinary College, North Mymms, Hertfordshire AL9 7TA, UK.
Nature. 2005 Dec 8;438(7069):753-4. doi: 10.1038/438753a.
Maximum running speed is constrained by the speed at which the limbs can be swung forwards and backwards, and by the force they can withstand while in contact with the ground. Humans sprinting around banked bends change the duration of foot contact to spread the time over which the load is applied, thereby keeping the force on their legs constant. We show here that, on entering a tight bend, greyhounds do not change their foot-contact timings, and so have to withstand a 65% increase in limb forces. This supports the idea that greyhounds power locomotion by torque about the hips, so--just as in cycling humans--the muscles that provide the power are mechanically divorced from the structures that support weight.
最大奔跑速度受四肢前后摆动速度以及与地面接触时所能承受的力的限制。人类在倾斜弯道上冲刺时会改变足部接触地面的时长，以分散施加负荷的时间，从而使腿部所受的力保持恒定。我们在此表明，进入急转弯时，灵缇犬不会改变其足部接触时间，因此必须承受肢体力量增加65%的情况。这支持了灵缇犬通过髋部扭矩来驱动运动的观点，所以——就像骑自行车的人类一样——提供动力的肌肉在机械上与支撑体重的结构相分离。
