McCarty C A, Thomason J J, Gordon K, Burkhart T, Bignell W
Department of Biomedical Science, University of Guelph, Ontario, Canada.
Equine Vet J. 2015 Mar;47(2):223-9. doi: 10.1111/evj.12252. Epub 2014 Apr 9.
We wished to add to the existing baseline data on impact loading of the distal limb as a precursor to assessing the potential role of impact in injury and joint disease.
To examine the effect of 3 hoof-strike conditions (toe first, flat and heel first) and 2 specimen masses (with and without a ballast of ∼2% body mass) on impact deceleration and vibration frequencies and energies at the hoof, first phalanx and third metacarpal.
Biomechanical experiments in cadaver material.
Eight cadaver limbs were subjected to randomised, repeated controlled trials, in which the hoof was struck by a pendulum impact-testing machine (impact velocity, 3.55 m/s) in the 3 strike and 2 mass conditions. Data from triaxial accelerometers on the hoof, first phalanx and third metacarpal quantified, for all trials, the peak impact acceleration, frequencies in the first 6.4 ms following impact, the frequency with the most energy, 95% of the total energy and the frequency at 95% cumulative energy. The effects of the strike and mass conditions on each variable were statistically tested using repeated-measures ANOVA (α = 0.05).
Signal energy reaching the third metacarpal was 6-31% of that at the hoof. A heel-first strike produced the largest peak accelerations and highest frequencies among all strike conditions, and changing the mass had no effect regardless of strike condition.
Large accelerations that occur upon impact of the hoof with the ground are attenuated by the distal structures of the equine limb, but still carry considerable energy within the signal that could be damaging to tissue and are dependent on hoof-strike condition but not ballast. Our results suggest that impact loading on the hoof could be a factor in contributing to bone injury and joint disease in the distal limb.
我们希望补充有关远端肢体冲击负荷的现有基线数据，以此作为评估冲击在损伤和关节疾病中潜在作用的前期工作。
研究3种蹄部撞击条件（趾先着地、平踏和跟先着地）以及2种标本质量（添加约2%体重的配重和不添加配重）对蹄部、第一指骨和第三掌骨处的冲击减速度、振动频率和能量的影响。
在尸体材料上进行生物力学实验。
对8条尸体肢体进行随机、重复的对照试验，在3种撞击条件和2种质量条件下，用摆锤冲击试验机（冲击速度为3.55米/秒）撞击蹄部。在所有试验中，通过安装在蹄部、第一指骨和第三掌骨上的三轴加速度计获取的数据，对峰值冲击加速度、冲击后最初6.4毫秒内的频率、能量最大的频率、总能量的95%以及累积能量达到95%时的频率进行量化。使用重复测量方差分析（α = 0.05）对撞击和质量条件对每个变量的影响进行统计学检验。
到达第三掌骨的信号能量为蹄部信号能量的6% - 31%。在所有撞击条件中，跟先着地的撞击产生的峰值加速度最大、频率最高，并且无论撞击条件如何，改变质量均无影响。
马蹄与地面撞击时产生的大幅加速度会被马肢体的远端结构衰减，但信号中仍携带相当大的能量，这可能会对组织造成损伤，且这种能量取决于蹄部撞击条件而非配重。我们的研究结果表明，蹄部的冲击负荷可能是导致远端肢体骨损伤和关节疾病的一个因素。
