犬类对三足运动的地面反作用力适应性
Ground reaction force adaptations to tripedal locomotion in dogs.
作者信息
Fuchs A, Goldner B, Nolte I, Schilling N
机构信息
University of Veterinary Medicine Hannover, Foundation, Small Animal Clinic, Hannover, Germany.
Friedrich-Schiller-University, Institute of Systematic Zoology and Evolutionary Biology, Jena, Germany.
出版信息
Vet J. 2014 Sep;201(3):307-15. doi: 10.1016/j.tvjl.2014.05.012. Epub 2014 May 13.
To gain insight into the adaptive mechanisms to tripedal locomotion and increase understanding of the biomechanical consequences of limb amputation, this study investigated kinetic and temporal gait parameters in dogs before and after the loss of a hindlimb was simulated. Nine clinically sound Beagle dogs trotted on an instrumented treadmill and the ground reaction forces as well as the footfall patterns were compared between quadrupedal and tripedal locomotion. Stride and stance durations decreased significantly in all limbs when the dogs ambulated tripedally, while relative stance duration increased. Both vertical and craniocaudal forces were significantly different in the remaining hindlimb. In the forelimbs, propulsive force increased in the contralateral and decreased in the ipsilateral limb, while the vertical forces were unchanged (except for mean force in the contralateral limb). Bodyweight was shifted to the contralateral and cranial body side so that each limb bore ~33% of the dog's bodyweight. The observed changes in the craniocaudal forces and the vertical impulse ratio between the fore- and hindlimbs suggest that a nose-up pitching moment occurs during the affected limb pair's functional step. To regain pitch balance for a given stride cycle, a nose-down pitching moment is exerted when the intact limb pair supports the body. These kinetic changes indicate a compensatory mechanism in which the unaffected diagonal limb pair is involved. Therefore, the intact support pair of limbs should be monitored closely in canine hindlimb amputees.
为深入了解三肢行走的适应机制,并增进对肢体截肢生物力学后果的认识,本研究在模拟犬后肢缺失前后,对其动力学和时间步态参数进行了研究。九只临床健康的比格犬在装有仪器的跑步机上小跑,比较了四足行走和三肢行走时的地面反作用力以及足落模式。当犬以三肢行走时,所有肢体的步幅和站立持续时间均显著缩短,而相对站立持续时间增加。剩余后肢的垂直力和头尾向力均有显著差异。在前肢中,对侧肢体的推进力增加,同侧肢体的推进力减小,而垂直力不变(对侧肢体的平均力除外)。体重转移到对侧和身体头部一侧,使得每条肢体承受犬体重的约33%。观察到的头尾向力变化以及前后肢之间的垂直冲量比表明,在受影响肢体对的功能步期间会出现抬头俯仰力矩。为在给定步幅周期内恢复俯仰平衡,当完整肢体对支撑身体时会施加低头俯仰力矩。这些动力学变化表明存在一种补偿机制,其中未受影响的对角肢体对参与其中。因此,对于犬后肢截肢者,应密切监测完整的支撑肢体对。