Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden.
PLoS One. 2023 Apr 6;18(4):e0284105. doi: 10.1371/journal.pone.0284105. eCollection 2023.
Many horses, just before and during their athletic career, show vertical movement asymmetries, to the same degree as clinically lame horses. It is unknown whether these asymmetries are caused by pain or have alternative explanations, such as inherent biological variation. In the latter case, movement asymmetries would be expected to be present at a very young age. This study aimed to investigate the prevalence of movement asymmetries in foals. Motion analysis, using an inertial measurement unit-based system (Equinosis), was performed on 54 foals (31 Swedish Warmbloods, 23 Standardbreds) during straight-line trot. The foals were between 4-13 weeks old and considered sound by their owners. Differences between the vertical minimum and maximum values recorded for the head (HDmin, HDmax) and pelvis (PDmin, PDmax) between left and right stance were calculated for each stride and an average was computed for each trial. Thresholds for asymmetry were defined as absolute trial mean >6 mm for HDmin and HDmax, and >3 mm for PDmin and PDmax. These thresholds were exceeded for one or several parameters by 83% of Standardbred foals and 45% of Swedish Warmblood foals, demonstrating surprisingly high prevalence of asymmetries in young foals, although the risk of repetitive strain injuries and cumulative risk of trauma injuries was expected to be low in this age group. Standardbred foals showed similar prevalence of asymmetries to that reported previously for yearling Standardbred trotters, so relatively higher prevalence of movement asymmetries may be expected among trotters as a breed. In general, vertical head and pelvic movement asymmetries can be anticipated among foals considered sound by their owners. A better understanding of the aetiology of asymmetries is needed for correct interpretation of objective symmetry measurements in different populations of horses.
许多马在运动生涯前后都会出现垂直运动的不对称性，其程度与临床跛行的马相同。目前尚不清楚这些不对称性是由疼痛引起的，还是有其他解释，例如固有生物学变异。在后一种情况下，运动不对称性预计会在很小的时候就存在。本研究旨在调查驹马运动不对称性的流行情况。使用基于惯性测量单元的系统（Equinosis）对 54 匹驹马（31 匹瑞典温血马，23 匹标准马）进行直线小跑时的运动分析。这些驹马年龄在 4-13 周之间，其主人认为它们是健康的。计算了左右支撑时头部（HDmin、HDmax）和骨盆（PDmin、PDmax）的垂直最小值和最大值之间的差异，并为每个步幅计算平均值，为每个试验计算平均值。将不对称的阈值定义为绝对试验平均值>6mm 用于 HDmin 和 HDmax，>3mm 用于 PDmin 和 PDmax。这些阈值被 83%的标准马驹和 45%的瑞典温血马驹的一个或多个参数超过，表明年轻驹马的不对称性发生率很高，尽管在这个年龄段，重复性劳损和累积创伤损伤的风险应该很低。标准马驹的不对称性发生率与以前报道的成年标准马的小跑相似，因此，作为一个品种，跑步马的运动不对称性可能会更高。总的来说，运动健康的驹马可能会出现垂直头部和骨盆运动的不对称性。需要更好地了解不对称性的病因，以便正确解释不同马群的客观对称测量结果。
