Butcher Michael T, Ashley-Ross M A
Department of Biology, Wake Forest University, P.O. Box 7325, Winston-Salem, NC 27109, USA.
J Biomech. 2002 May;35(5):563-71. doi: 10.1016/s0021-9290(01)00223-8.
Fetlock joint kinematics during galloping in 2-, 3-, 4-, and 5-year-old Thoroughbreds in race training were quantified to determine if differences due to age could account for the observation that 2-year old Thoroughbred racehorses incur a high number of injuries to the bones and soft tissues in the distal forelimbs during training and at the outset of racing. Twelve Thoroughbred racehorses were videotaped in the sagittal plane at 250 frames/s during their daily galloping workout on a 7/8 mile sand-surface training track. Four galloping strides were recorded for each horse and subsequently digitized to determine fetlock joint angles of the leading forelimb during the limb support period of a stride. Four kinematic variables were measured from each stride's angular profile: angle of fetlock joint dorsi-flexion at mid-stance, negative angular velocity, positive angular velocity and time from hoof impact to mid-stance phase of limb support. The 2-year old Thoroughbreds had significantly quicker rates of dorsi-flexion of their fetlock joints than 3- (p=0.01), 4- (p=0.01), and 5-year old (p<0.01) Thoroughbreds following impact of the leading forelimb during moderate galloping (avg. 14 m/s). Higher rates of dorsi-flexion in young Thoroughbreds may reflect immaturity (lack of stiffness) of the suspensory apparatus tissues.
对处于比赛训练阶段的2岁、3岁、4岁和5岁纯种赛马在飞奔时的系关节运动学进行了量化，以确定年龄差异是否可以解释以下观察结果：2岁的纯种赛马在训练期间和比赛开始时，前肢远端的骨骼和软组织会受到大量损伤。在一条7/8英里长的沙地训练跑道上，12匹纯种赛马在日常飞奔训练时，以每秒250帧的速度在矢状面进行录像。每匹马记录4个飞奔步幅，随后进行数字化处理，以确定前肢在一个步幅的肢体支撑期内的系关节角度。从每个步幅的角度轮廓中测量4个运动学变量：站立中期系关节背屈角度、负角速度、正角速度以及从蹄着地到肢体支撑中期的时间。在中等飞奔速度（平均14米/秒）下，领先前肢着地后，2岁的纯种赛马系关节背屈速度明显快于3岁（p = 0.01）、4岁（p = 0.01）和5岁（p < 0.01）的纯种赛马。年轻纯种赛马较高的背屈速度可能反映了悬韧带组织的不成熟（缺乏刚度）。
