PDF(Pubmed)
Abstract：
Head and pelvis vertical movement asymmetries in horses are often evaluated under different conditions yet better understanding is required of how these asymmetries are altered by factors such as surface type or circle size. This study investigated how stride duration, surface and lungeing in circles of different sizes influenced objectively measured head and pelvis movement asymmetries in riding horses in full training. Movement asymmetries were recorded with body mounted accelerometers and were based on the differences between the two vertical displacement minima or maxima of head (HDmin, HDmax) and pelvis (PDmin, PDmax) within a stride cycle. Each horse was evaluated during straight-line trot and during lungeing (d = 10m/15m) on hard and soft surfaces at slow and fast speed (determined by stride duration). All horses (N = 76) had at least one movement asymmetry parameter above a predefined thresholds (|HDmin| or |HDmax| >6mm, |PDmin| or |PDmax| >3mm) during a straight line trot on hard surface (baseline). The horses were assigned to a \'predominant asymmetry\' group (HDmin, HDmax, PDmin, PDmax) based on which movement asymmetry parameter was the greatest during the baseline condition; the head movement asymmetry values were divided by two to account for the difference in magnitude of the thresholds. Analysis was carried out for each predominant asymmetry group separately using linear mixed models-outcome variable: predominant asymmetry parameter; random factor: horse; fixed factors: surface, direction with stride duration as covariate (P<0.05, Bonferroni post-hoc correction). The \'direction\' conditions were either a straight-line locomotion (\'straight\') or lungeing with lungeing conditions further classified by circle diameter and by whether the limb which the predominant asymmetry was assigned to (\'assigned limb\') was on the inside or outside of the circle (\'inside10\', \'inside15\', \'outside10\', \'outside15\'). Only parameters related to asymmetrical weight-bearing between contralateral limbs (HDmin, PDmin) were affected by changes in stride duration-the most common pattern was an increase in asymmetries as stride duration decreased. Only pelvic movement asymmetries were affected by lungeing. When the assigned hindlimb was on the inside of the circle, the PDmin asymmetries increased and PDmax asymmetries decreased compared to the straight-line condition. With the assigned hindlimb on the outside, PDmin asymmetries decreased but PDmax asymmetries did not change. Trotting on 10 m circle compared to 15 m circle did not increase movement asymmetries. In conclusion, circular motion and changes in stride duration altered movement asymmetries identified in horses in full ridden work but no changes were seen between the soft and hard surfaces. These patterns should be further investigated in clinically lame horses.
摘要：
通常在不同的条件下评估马的头部和骨盆垂直运动不对称性，但需要更好地了解这些不对称性如何因表面类型或圆形尺寸等因素而改变。这项研究调查了跨步持续时间，不同大小的圆圈中的表面和腹部运动影响了全面训练中骑马时客观测量的头部和骨盆运动不对称性。运动不对称性是用人体安装的加速度计记录的，并且是基于头部的两个垂直位移最小值或最大值之间的差异（HDmin，HDmax)和骨盆(PDmin,PDmax)在跨步周期内。每匹马在直线小跑和在硬表面和软表面上以缓慢和快速的速度（由跨步时间确定）进行训练（d=10m/15m）时进行评估。所有马（N=76）的至少一个运动不对称性参数高于预定义阈值（|HDmin|或|HDmax|>6mm，|PDmin|或|PDmax|>3mm)在硬表面(基线)上直线小跑期间。马匹被分配到一个“主要不对称”组(HDmin，HDmax,PDmin,PDmax）基于在基线条件下哪个运动不对称参数最大；将头部运动不对称值除以2以说明阈值大小的差异。使用线性混合模型-结果变量分别对每个主要不对称组进行分析：主要不对称参数；随机因素：马；固定因素：表面，以跨步持续时间为协变量的方向(P<0.05，Bonferroni事后校正)。\'方向\'条件是直线运动（\'直线\'）或与直行条件的直行，进一步按圆直径以及按主要不对称分配的肢体（\'分配的肢体\'）是否在圆的内侧或外侧（\'inside10\'，\'inside15\',\'外部10\',\'outside15\'）。仅与对侧肢体之间的不对称负重有关的参数（HDmin，PDmin）受到跨步持续时间变化的影响-最常见的模式是随着跨步持续时间的减少，不对称性增加。只有骨盆运动的不对称受到影响。当指定的后肢在圆的内侧时，与直线条件相比，PDmin不对称性增加，PDmax不对称性减少。指定的后肢在外面，PDmin不对称性降低,但PDmax不对称性没有改变。与15m圆相比，在10m圆上的微动并没有增加运动不对称性。总之,圆周运动和步幅的变化改变了在全骑工作中确定的马匹的运动不对称性，但在软表面和硬表面之间没有看到变化。这些模式应该在临床跛脚马中进一步研究。
